1

M. SC (BOTANY)

SEMESTER I

CORE 3

ANATOMY AND DEVELOPMENTAL BOTANY

PRACTICAL GUIDE

Department of Botany

St. Xavier’s college (Autonomous) (Re-Accredited with “A” Grade by NAAC with a CGPA of 3.50)

(College with Potential for Excellence by UGC)

Palayamkottai – 627 002 JULY - 2018

DR. V. IRUDAYARAJ

Dr. V. I

ruda

yara

j, Dep

t. of

Bot

any,

SXC, Pala

yam

kotta

i

2

CONTENTS

Practical syllabus for Anatomy and developmental botany - 3

Caliberation of microscope and micrometry ….. ….. ... - 4

Clearing techniques for microscopic observation .. …. ….. - 7

Preparation of microslide for microscopic observation by

Taking hand sections (Simple staining and temporary wet mounting) - 8

Microtomy … …. …. … …. - 9

Double staining of microsections (Safranin & Fast gree) and

Making permanent slides ………. ……… …… ….. …. - 15

Observation of meristematic tissue … …. …. ….. …. - 16

Observation of simple permanent tissues …….. ……. ……. - 17

Complex permanent tissues (Xylem, Phloem— Wood anatomy) ……. - 19

Parts of a tree system … … … - 20

Complex permanent tissue—Maceration techniques - 21-22

Microscopic structure of wood ….. ….. … - 23

Scientific/botanical description of wood …… …. – 28

Description of common Indian timbers

Acacia .. .. .. -29

Mango .. .. .. - 31

Neem .. .. .. - 33

Red sanders .. .. .. - 35

Teak .. .. .. - 37

Rubber .. .. .. - 39

Banyan .. .. .. - 41

Stomatal types in angiosperms .. .. .. - 44

Cell inclusions (Ergastic substances) .. .. .. - 49 EMBRYOLOGY AND MORPHOGENESIS:

Organization/structure of anthers in flowers .. .. .. - 55

Pollen morphology—Palynology .. .. .. - 57

Ovaries, ovules and their modifications .. .. .. - 58

Determination of pollen viability .. .. .. - 60

Effect of sucrose and pH on pollen germination .. .. .. - 61

Effect of IAA and sucrose on apical bud .. .. .. - 62

Effect of disruption of vascular continuity and regeneration of

vascular tissues (Wound healing response in dicots and monocots) - 63

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I M. Sc (Botany) - I Semester PRACTICALS-2

CELL BIOLOGY AND GENETICS, ANATOMY& DEVELOPMENTAL BOTANY

(Sub. Code: 15PBOTR16)

ANATOMY:

Calibration of microscope and micrometry

Preparation of hand sections, maceration and clearing techniques

Temporary and permanent mounting of whole specimens and sections

Microtome sectioning techniques

Examination of different cell and tissue types

Wood anatomy of some common Indian timbers such as:

Mangifera indica, Tectona grandis, Azadirachta indica, Thespesia populnea

and Pterocarpus sp.

Study of anatomical characters of taxonomic importance-epidermal characters

-study of stomata; cell inclusions.

EMBRYOLOGY:

Organization of anthers and pollens, pollen wall patterns, pollen germination

and pollen tube growth

Study on ovary, ovules and their modification

Effect of sucrose and pH on pollen germination

Determination of pollen viability

MORPHOGENESIS:

Disruption of vascular continuity and regeneration of vascular tissues

Effect of sugars and IAA on vascular tissue regeneration

Effect of IAA and sugar on the apical bud

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CALIBERATION OF MICROSCOPE AND MICROMETRY

Aim: To measure the size of the given microscopic specimens (Length and width of sto-

matal guard cell from leaf, diameter of pollen grains/spores) by micrometry.

Requirements: Compound-light-Microscope, Stage Micrometer, Ocular Micrometer,

Micro slides, cover glass.

Principle: Measurement of microscopic objects by using microscope is called Microme-

try. Microscopic objects are measured by using micrometer-scale. There are two kinds of

Micrometers viz. Ocular Micrometer, Stage Micrometer. The Ocular Micrometer is a cir-

cular plastic or glass disc on which a line is drawn which is further sub-divided into 100

divisions. The value of each part is not known. The calibration is done by comparing the

scale of Ocular Micrometer with that of stage micrometer. A stage micrometer is a mi-

croscopic slide in which a line of 1mm is drawn in the center. This line is again divided

into 10 parts and each part into 10 smaller parts. Thus 1mm is divided into 100 parts each

measuring 0.01mm or 10 microns (1mm= 1000 microns or micrometer - µm).

Procedure:

Calibration of the Microscope:

Place the Ocular Micrometer on the metal diaphragm in the eyepiece of the Mi-

croscope. Place the Stage Micrometer on the stage of the Microscope and its scale is

brought into focus. Both the lines - one on the Ocular micrometer and the other on the

stage micrometer are visible. By moving the stage micrometer and rotating the eyepiece,

both the lines are made to coincide. i.e overlapping each other at the starting point. The

exact overlapping points of the other ends of both the lines are observed. Count the num-

ber of divisions between the overlapping lines both in Ocular micrometer and Stage mi-

crometer. For example 70 divisions of the stage micrometer is equal to 50 divisions of the

ocular micrometer. Actual value of one division of OM is calculated as follows:

No. of divisions of SM x 10

Value of 1 division of OM = ------------------------------------------- = …..µm

No. of divisions of OM

Note: It is to be noted that this value of each OM division will vary whenever a new com-

bination of objective lens and eye piece lens are used. Therefore, it is necessary to make

calibration of the OM at each combination of objective and eye piece lenses.

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CALIBERATION OF OCULAR MICROMETER WITH STAGE MICROMETER

No. of divisions of SM x 10

Value of 1 division of OM = ------------------------------------------- = …..µm

No. of divisions of OM

Calculation of stomatal frequency & Stomatal Index

S.

No.

Number of stomata per micro-

scopic field

Number of epidermal cells per

microscopic field

1

2

3

4

5

6

7

8

9

10

Total

Average Total / 10 = . . . . . . . . Total / 10 = . . . . .

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No. of stomata per microscopic field

Stomatal frequency = --- --------------------------------------------------- x 1000000

(No. of stomata per mm2 ) Actual area of the microscopic field (µm2)

Stomatal Index = Number of stomata per 100 epidermal cells

Number of stomata

Stomatal index = ----------------------------------------------------------------- X 100

Total number of epidermal cells

+

Total number of stomata

Calculation of length / width / diameter of plant cells ( Stomatal guard cells / pollen grains etc.)

Conclusion:

S. No. Length and width of stomatal

guard cells

(Number of ocular divisions)

Diameter of the pollen grains (Number of ocular divisions)

1 . . . . x . . . . . . . . . . .

2 . . . . x . . . . . . . . . . .

3 . . . . x . . . . . . . . . . .

4 . . . . x . . . . . . . . . . .

5 . . . . x . . . . . . . . . . .

6 . . . . x . . . . . . . . . . .

7 . . . . x . . . . . . . . . . .

8 . . . . x . . . . . . . . . . .

9 . . . . x . . . . . . . . . . .

10 . . . . x . . . . . . . . . . .

Aver-

age

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CLEARING TECHNIQUES FOR MICROSCOPIC OBSERVATION

Principle: Transmission light microscopy as a matter of principle requires the passage of

light through the specimen into the optical system of the microscope. For the study of

plant and animal tissue, this requirement is traditionally fulfilled by slicing the tissue into

sections sufficiently thin to permit light transmission. An alternative to sectioning meth-

ods, which are by nature quite arduous, is provided by a variety of clearing techniques. In

these techniques, thick masses of tissue are made translucent through specific chemical

treatment.

Requirements: Clearing agents, glassware, specimens (leaves), microslides, safranin

stain, microscope.

Clearing solution:

A. FPA50 (formalin, propionic acid, 50% ethanol; 5:5:90)

B. Carnoy's (Farmer's) fluid (absolute ethanol, acetic acid; 3:1)

C. Randolph's modified Navashin fluid (Solution A: chromic acid, 1 g; acetic acid, 7 cc;

water, 92 cc. Solution B: formalin, 30 cc; water, 70 cc. Mix equal portions of A and B

just before using.)

D. Ethanol: 70%, 95%, and absolute

E. 4½ clearing fluid (lactic acid, chloral hydrate, phenol crystals, clove oil, xylene;

2:2:2:2:1, by

weight)

F. Bordeaux Red 4½ clearing fluid (0.2 mg dye/g clearing fluid)

G. BB-4½ clearing fluid (4½ clearing fluid, benzyl benzoate; 9:1, by weight)

H. Lactic acid saturated with chloral hydrate.

Procedure: Keep the plant specimens (fresh leaves) in at least three different clearing

solutions, keep it for few hours. If necessary boil in water bath. Note the difference in the

transparency of the material. Observe the venation pattern, veinlets under the microscope

after staining with safranin. Dr.

V. Iru

daya

raj, D

ept.

of B

otan

y, SXC, P

alaya

mko

ttai

8

Requirements: Slides, cover slips, droppers or pipettes, brush, dissection needles, razor

blades, minicutter and any chemicals or stains you plan to use. Simple steps to take

hand section of plant materials and to make temporary wet mounting.

Take the material to be sectioned and cut into small pieces.

Take a piece of pith and cut all the surfaces evenly and neatly.

Half split the pith on one surface and place the specimen inside the split.

Cut the specimen along with the pith to make even level.

Take as many sections as possible by using new razor blade.

Select few good sections and stain (Safranin) them by keeping on a microslide.

Wash the stained sections with water to remove excess stain.

Take a clean microslide, put a drop of glycerine exactly at the center of the slide.

Place one stained section on the drop of glycerine and place the cover glass without any air bubble.

Remove the excess glycerine by using blotting paper. Observe under a microscope.

Stain the selected section by

placing on a microslide.

Mount the stained section on

the microslide by putting a

cover glass without any air

bubble. Remove the excess

of water /glycerine by blot-

ting with a blotting paper.

PREPARATION OF MICROSLIDE FOR MICROSCOPIC OBSERVATION BY TAKING HAND SECTIONS

(SIMPLE STAINING AND TEMPORARY WET MOUNTING)

Dr. V. I

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SXC, Pala

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MICROTOMY

Aim: To make thin sections of plant materials by using microtome.

Principle:

Microtome: Microtome is an instrument used for taking microsections of plant and ani-

mal tissues (Gr. Micro = small; tamein = to cut). There are different kinds of Micro-

tomes. The most commonly used one is the Rotary Microtome. The circular drive wheel

is rotated in a circular motion to move the specimen holder up and down against the cut-

ting edge of the knife. Thin sections of required thickness can be made by using micro-

tome. A rotary microtome has the following major parts: Main body, drive wheel, speci-

men holder, knife, knife holder, reversal handle and strong sledge (Fig.).

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Procedure: To make sections in microtome the prefixed material(s) (Fixation is usually

done in FAA: Alcohol: Acetic Acid: Formalin: Water – 50: 5 : 10 : 35 ml) should be em-

bedded in supporting material, usually paraffin wax and the material should be rigid

enough with uniform consistency and texture. The texture / rigidity of the material and

the supporting material should be equal enough to get uniform sections. So the prefixed

material is first infiltered with paraffin wax, the infiltered material is embedded in paraf-

fin wax to make blocks. The blocks with the embedded material is fixed in the microtome

and sections are made.

Paraffin infiltration:

1. Infiltration of paraffin wax into the tissue should be carried out in gradual steps.

2. Fine shaves of paraffin wax are to be added in very small quantities to the specimen

tube containing the materials in 100% clearing agent (Xylol).

3. Further addition is to be carried out only after the shaves added have completely dis-

solved. Thus, wax shaves are added in small quantities until the clearing agent becomes

saturated with wax.

4. To hasten dissolution of the paraffin wax, the specimen tubes can be kept in thermostat

set at specific temperatures. The specimen tube should be kept open in the thermostat to

facilitate evaporation of the clearing agent.

5. The saturated wax solution is to be decanted and fresh pure molten wax is to be added.

This should be done twice or thrice until the smell of clearing agent disappears.

6. The wax that is added after the level of saturation will float as a film. This stage is at-

tained in 2 or 4 days time. This kind of slow and gradual infiltration is preferred as tissue

damage may result out of rapid infiltration.

7. After 8 to 10 Hours of keeping the specimen tube in the thermostat, the wax solution is

decanted. Pure molten wax is added to the tube. About 6 to 8 hours later, the specimen

tube is to be tested for any possible remnants of the clearing agent (by smelling it). If the

smell of the clearing agent is still lingering in the specimen tube, the materials are to be

changed in pure fresh molten wax twice or thrice until the smell of the clearing agent is

not sensed. The presence or absence of clearing agent can also be tested by placing a

drop of wax solution on a glass plate. If it forms hard button shape after solidification

there is no clearing agent. If there is clearing agent the drop will be of greasy or sticky.

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Paraffin embedding:

1. Make a rectangular paper-boat of approximately 1.5 x 1 x 0.5 inch size by using thick

papers like Herbarium sheet, post card, invitation card etc.

2. Coat the inner surface of the paper boat with oil or Vaseline. Keep the boat in plain

surface.

3. Take the specimen tube containing the materials in the molten wax, shake well and

pour into the paper boat along with material. The material should be completely im-

mersed in the wax solution.

4. Before the wax solidifies, by using heated scalpel or needle, arrange the material in

neat horizontal manner with sufficient space if there are more materials.

5. Solidification of the molten wax in the paper boat can be delayed by carrying out this

exercise by keeping the paper boat on a copper table which is heated by a spirit lamp kept

underneath.

6. After arranging the materials in neat manner, the boat is left undisturbed until the wax

solidifies. The process of solidification can be hastened by floating the boat with the wax

in cool water contained in a tray.

7. After solidification is complete, the paper boat can be removed and the wax block can

be separated. The blocks are cut into convenient size with one material in one block. All

the surfaces are trimmed neatly.

Fixing the wax block on the specimen holder: Fix the wax block on the specimen hold-

er (wooden or metallic) by using molten wax. The block of wax containing the material

should be oriented on the specimen holder keeping the required plant of section in mind.

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Operating the Microtome:

A. Setting the specimen holder:

Rotate the drive wheel slightly to move the specimen holder up. Move the safety

catch to the lock position so that the specimen holder does not move down.

Now rotate the reversal handle so that the specimen holder is moved back to the full-

est extent. Fix the wooden or metallic mount with paraffin block in the specimen

holder.

Check if the plane of the material in paraffin block is as desired. If not, set it by rotat-

ing the mount and screw it firmly. Check if all the screws in the specimen holder

are firm.

B. Setting the knife holder:

Move the knife holder to a desired position towards the specimen holder.

Slide the knife into the knife holder and tighten the screws.

Move the knife holder on the sledge forward and backward so that the upper cutting

edge is just in line with the front edge of the paraffin block.

Viewing from the side, adjust the angle of the knife leaving just enough clearance

angle.

Tighten the screws of the knife holder so that the desired clearance angle is main-

tained and the cutting edge of the knife just meets the paraffin block.

Now carefully release the safety catch while holding the drive wheel handle to

prevent sudden sliding of the specimen holder.

C. Taking sections:

Move the drive wheel in a controlled manner so that the specimen holder moves gen-

tly up and down. All the while watch carefully if the paraffin block just passes

past the cutting edge of the knife.

Leave the specimen holder down in the resting position and recheck if the screws of

the knife holder are firm.

Decide the thickness of the section rotating the micrometer screw. Check if the indi-

cator line in the dial is pointing a particular division and not in between divisions.

Start rotating the drive wheel, first slowly and then a little fast at constant rhythmic

circular movement. (Note whether the paraffin block advancing with every verti-

cal movement of the specimen holder).

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When the paraffin block strikes against the cutting edge of the knife paraffin-

embedded sections are cut from the block.

The successive sections remain attached to the cutting edge pushing the previous sec-

tions forward which form a ribbon. As sectioning continues, the ribbon grows in

length.

Lift the farther end of the ribbon with the help of a needle wetted with formalin

water so that a cotinuous ribbon of sections is possible.

D. Fixing the ribbon containing microsections on slides:

Take a clean micro-slide, place a few drops of adhesive (Mayer‘s egg albumin: Equal

quantity of glycerine and egg albumin with small quantity of preservative like for-

malin or Sodium salicylate) and make a smear on the entire surface on one side of

the slide using an index finger.

Keep the slide smeared with adhesive on a hot plat or show it over a flame. Carefully

flood formalin water on the surface of the slide and allow it to stand.

As soon as the formalin water on the slide becomes lukewarm, the ribbon is cut to

desired length and the segment is carefully lifted using dissecting needles. The

segment is carefully floated in the lukewarm formalin water on the slide.

As the formalin water gets warmer, the ribbon stretches. The two ends of the segment

are gently forced apart so that the segment becomes straight. The wax ribbon seg-

ments can be fixed on the slide leaving just enough space for label. Two or three

rows of segments can also be fixed on one slide.

The warm formalin water is drained so that the wax ribbon segment gets fixed on the

slide. Such slides, to which ribbons have been fixed, are taken to the next stage of

staining after dewaxing.

Note: A length of continuous ribbon is possible when the following conditions are satis-

fied.

Proper infiltration of the material is achieved.

Paraffin block is of right consistency.

Right clearance angle.

Knife is in firm grip on the knife holder.

The knife edge is sharp without nicks.

There is no draught of air.

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E. Dewaxing: Before staining, the slide and the sections are to be dewaxed as follows:

Transfer and leave the slide(s) in pure xylol contained in a Coplin jar covered with

the lid for about 10 to 15 minutes.

Take out the slide and check if the wax in and around the sections have dissolved

completely. If not, allow sufficient time for the wax to dissolve.

After dewaxing, take out the slide(s) and wipe the under surface with a clean dry

cloth and then very carefully wipe out the area around the sections on the other

side. Take care not to wipe out the sections. Now the sections are ready for stain-

ing.

Microtome Ribbon on Leica Microtome Paraffin ribbon on slide

Dr. V. I

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DOUBLE STAINING OF MICRO-SECTIONS (SAFRANIN & FAST GREEN)

AND MAKING PERMENANT SLIDES

Aim: To make permanent slides with double staining (Safranin & Fast green)

Requirements: Sections of plant specimens (Free hand sections or dewaxed sections

from microtome), embryo cups with lids, micro-slides, cover glasses, dissection needles,

brush, microscope, 100% Alcohol (Ethanol), Safranin powder, Fast green powder, Xylol,

Clove oil, DPX mountant.

Bring the sections up to 70% alcohol and stain them with 1% Safranin in 70%

Alcohol for few minutes. Wash the excess stain in 70% Alcohol.

Dehydrate the sections in Alcohol series (80%, 90% and 100% Alcohol) for

10-20 seconds in each.

Counter stain with 1% Fast Green in 100% Alcohol for few seconds. Wash

the excess stain in Clove oil.

Clear the section in a mixture of 50 parts of clove oil, 25 parts Absolute Alco-

hol and 25 parts xylol for a few moments.

Remove the clearing agent by washing the slide a few seconds in Xylol. Ap-

pearance of any cloudiness in the section or slide indicates the presence of

moisture. In such case a few drops of absolute alcohol are added over the sec-

tions to ensure complete dehydration.

Give two changes in Xylol and mount in mounting medium Canada Balsam or

DPX without the presence of any air bubble. Allow the mounted slides to dry

at room temperature.

Scheme:

Sections ——> 30% —–> 50% —–-> 70% Alcohol —-> Safranin in 70% Alcohol-—>

70% Alcohol—> 80% —-> 90% -->100% Alcohol —> Fast green in 100% Alcohol —>

Clove oil —>Clove oil + Alcohol + Xylol (50:25:25) —> Xylol —-> Mount in DPX.

Note: Submit at least five double stained permanent slides for evaluation.

Dr. V. I

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OBSERVATION OF MERISTEMATIC TISSUE

Aim: To study the shoot and root meristems.

Principle: Plants are made up of different kinds of tissues for different purposes, such as

meristematic tissue (growth by division of cells) and permanent tissue (no more growth

no more division). Meristematic cells are present at the shoot tip and root tip. The re-

maining parts of the plant are filled with permanent tissues called ground tissues

(parenchyma, colleenchyma and sclerenchyma) and vascular tissues (xylem and phloem).

Requirements: Shoot apices of Hydrilla, root apices of onion, petiole of cucurbits,

young and old stems and roots of some plants.

Procedure:

Study of apical meristems (Shoot/Root): Take a shoot apex of Hydrilla sp. Dissect out

the mature leaves and young leaves by using needles and dissecting microscope. Dissect

out the young leaves until you get a dome shaped apical meristem without covered by

any young leaf. Observe the tunica and carpus parts of the shoot meristem under a micro-

scope.

(Otherwise take L.S of shoot bud and observe under the microscope).

Take one or two root tips of onion, boil gently with 0.1N HCL, wash them in water, place

a tip (2-3mm) on a drop of safranin, put a cover glass, make a gentle press, observe under

a microscope.

Bud of Hydrilla with apical meristem Apical meristem of Onion root tip

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OBSERVATION OF SIMPLE PERMANENT TISSUES

Aim: To study the different simple permanent tissues in plants.

Principle: Plants are made up of different kinds of tissues for different purposes, such as

meristematic tissue (growth by division of cells) and permanent tissue (no more growth

no more division). The major parts of the plant body are filled with permanent tissues

called ground tissues (parenchyma, colleenchyma and sclerenchyma) and vascular tissues

(xylem and phloem). In order to perform different functions, there are different types of

simple permanent tissues like parenchyma, collenchyma, sclerenchyma and chlorenchy-

ma.

Requirements: Different parts (Stem, petiole, root, leaf) of different plant species.

Procedure: Take the transverse sections of different parts of the plants; stain with Safra-

nin; mount on microslides and observe under a Microscope. Observe and draw the differ-

ent tissue types present in different parts of the plants.

Parenchyma - Storage cells present in cortex and pith of stem and roots.

Collenchyma & Sclerenchyma - Mechanical tissue mostly present as hypodermis. Fi-

bers and sclereids are also present in plants to give mechanical support.

Chlorenchyma: Photosynhthetic cells with chloroplasts present in the mesophyll of

leaves (Palisade and spongy parenchyma)..

Dr.

V. Iru

daya

raj, D

ept.

of B

otan

y, SXC, P

alaya

mko

ttai

18

SIMPLE PERMANENT TISSUES

T. S. of Dicot old stem

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COMPLEX PERMANENT TISSUES (XYLEM & PLOEM)

Based on

TIMBER IDENTIFICATION MANUAL “MANUAL OF TIMBERS USED BY WOOD BASED HANDICRAFTS

INDUSTRY OF KERALA, UTTAR PRADESH AND RAJASTHAN”

http://www.wood-

database.com/

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Parts of a tree system

Because of the way trees grow, you can generally view three very different sur-

faces of wood, including transverse, radial, or tangential surfaces. The transverse or cross

-sectional surface is what you see when you look at the end of a board or log, and down

on a tree trunk. Growth rings are very apparent and appear as part of a circle on this sur-

face. The radial surface parallels the stem and passes through the pith. If you split a log in

half, you will produce two radial surfaces. The tangential surface is named because it is

the surface tangent to the growth rings. It is perpendicular to the direction of the wood

rays. The three surfaces of wood are important because wood structures appear very dif-

ferent depending on which surface is being viewed.

Pinus sylvestris T.S

R.L.S

T.L.S

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COMPLEX PERMANENT TISSUES (XYLEM AND PHLOEM)

Aim: To study the complex permanent tissues: Observation of xylem elements of a

wood by maceration technique (Jeffrey‘s method).

Principle: Unlike the simple permanent tissues which are made up of only one kind of

cells, the complex permanent tissues are made up of different kinds of cells. They can be

observed by various techniques like sectioning (T.S, T.L.S, R.L.S) and maceration. Ob-

servation of plant specimens by taking sections has a limitation in the sense that they re-

veal only two-dimensional details of the cells in the plane. The only reliable method

which reveals the cells in their entirety is maceration technique.

Requirements: Plant specimen (Pieces of wood of different species), Macerating fluid,

Specimen tube, Hot air oven, micro-slides, cover-glass, safranin stain, Microscope.

Macerating the tissue means dissociating the constituent cells of the tissue so that

entire cells can be viewed with the details of their third dimension. Maceration involves

treating the organ or part with chemicals to bring about softening of the tissue and disso-

lution of the intercellular cementing layer (middle lamella) so that cells dissociate very

easily. Cell wall thickening, pits and other cell wall characteristics are brought out effec-

tively in macerated materials.

Maceration fluid: A. 10% aqueous nitric acid and B. 10% Chromic acid in equal parts.

Keep solutions A and B separately and mix equal parts just before use.

Procedure:

Cut the fresh or dry specimen into small slices of about 2 or 3 mm thick. In

the case of very hard woody specimens, thin shaves can be obtained with the

help of a scalpel with a sharp cutting edge.

Boil the slices until all air has escaped and the slices have sunk to the bottom.

Take the slices in a specimen tube and pour Jeffrey‘s maceration fluid to

about thrice the volume of the specimen. Keep the specimen tube in a hot-air

oven.

Maceration time varies according to the material. Normally, cells begin to

separate in 24 hours.

At the end of 24 hours, try to pierce the specimen with a dissecting needle. If

maceration has occurred, the needle pierces the tissue very softly. If the tissue

is still hard, replace the maceration fluid with a fresh one and allow another

day.

Wash off the maceration fluid from the material thoroughly.

Take a small amount of macerated tissue on a microslide and macerate the

tissue further with the help of two dissection needles.

The macerated material is stained with safranin and observed under micro-

scope.

Note: To observe various elements of phloem, macerate the innermost layer of bark of

any tree with dilute HCl or Half strength macerating fluid.

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Maceration Technique II

Maceration fluid preparation: The maceration fluid is prepared by combining

1 part of a 30% solution of hydrogen peroxide,

4 parts of distilled water, and

5 parts of glacial acetic acid.

(Be sure to use a clean bottle and prepare this solution in the fume hood. Avoid contact

with the solution, wear gloves if necessary).

Procedure:

1. A variety of plant tissues such as soft pith tissues and woody xylem samples can be

studied using this technique. Cut plant tissues into small pieces (4 x 4 x 10 mm) and

place these into a vial containing the maceration fluid. The volume of fluid required is

approximately 10X the volume of the tissue.

2. Cap tightly. Place the vials in an oven at about 56∞C for 1-4 days. The duration of

maceration depends on the nature of the material. For soft tissues, such as the sun-

flower stem, 12-24 hours is sufficient.

3. If the maceration has been completed, the fluid will be clear and the tissues appear

whitish to translucent. Often, the tissue remains intact after this treatment. If the mate-

rial is not as described, add fresh maceration fluid and leave it for an additional one to

two days.

4. When the maceration is complete, gently rinse tissue in three changes of water

(several hours between each change) and leave the tissue in water overnight. Perform

these steps in the fume hood. Give the material a final rinse in water and store in wa-

ter or 30% glycerol solution.

5. If necessary, transfer a small mass of cells into a vial containing water, otherwise

simply process the tissue using the original vial. Be sure to cap the vial tightly, and

shake vigorously until the water becomes clouded with cells.

6. Apply a small drop of the mixture to a glass slide, cover it with a cover glass and ex-

amine. Alternatively, one can also stain the preparation by adding a drop of TBO to

increase the contrast.

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Microscopic structure of wood

Wood is composed different kinds of cells which are connected together in vari-

ous ways to form mass of wood. The process of separating the cells, needed for micro-

scopic observation, is called maceration. Cells of softwood species differ in appearance

from cells of hardwood species. All hardwoods contain, in varying amounts, vessel ele-

ments, fibers, longitudinal parenchyma and ray parenchyma. Only two cell

types, longitudinal tracheids and ray parenchyma formed the greatest volume of soft-

woods.

Structure and arrangement of pits:

Wood cells are equipped with pits. Pits serve as passages of communication be-

tween neighboring cells. Mature wood cells are dead, even in the living tree. Thus, most

cell lumina are empty. Pits are discontinuities in the secondary cell wall. there are two

main types of pits – simple and bordered. All pits have two essential components –

the pit cavity and the pit membrane. In the simple pit, the cavity is nearly constant in

width. In the bordered pit, the cavity narrows towards the cell lumen; typically, the mem-

brane is arched over by the secondary cell wall. The pit membrane cosists of primary

wall and middle lamella. As a rule, pits in the walls of adjoining cells appear in pairs

called pit-pairs, and the common membrane is therefore composed of two primary walls

and middle lamella.

Two complementary simple pits form a simple pit-pair, two bordered pits form

a bordered pit-pair. Some pit-pairs are semi-bordered; this is pairing of simple and bor-

dered pit. When a pit is not paired but solitary, it is called a blind pit. The structure of pit

membranes varies. In the bordered pits of most softwoods (spruce, fir, pine, Douglas-fir),

the central portion of the membrane is thickened; this is called torus.

Pits that occur in cross-fields of softwoods are termed according to appearance

as window-like, pinoid, cupressoid, piceoid and taxodioid. Cross-field is rectangle formed

(as observed on radial sections) by the horizontal walls of a ray parenchyma and the

walls of a vertical tracheid.

A common modification of bordered pit-pairs is the lateral displacement of the

membrane. This phenomenon, called aspiration, usually occurs when sapwood is trans-

formed into heartwood or when wood dries. In softwoods, the torus seals one of the pit

apertures and, therefore blocks the passage through the pit. Aspiration makes the wood of

fir, spruce and Douglas-fir difficult to impregnate with preservatives.

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Tracheids: The tracheids of softwoods are mostly or exclusively vertical. In some spe-

cies a few tracheids may be placed horizontally in association with rays. Axial (vertical)

tracheids comprise 90 % or more of the volume of softwoods. They are long, narrow

cells of a length about 75 – 200 times their diameter ( length: 3 – 5 mm, diameter: 0.02 –

0.04 mm). The morphology of tracheids is different in the earlywood and latewood. The

tracheids of earlywood are relatively thin-walled, polygonic to squarish in cross-section,

and have large lumina. Bordered pits are typical, located on their radial walls. On the

contrary, the tracheids of latewood possess thick walls, smaller lumina, and they tend to

be rectangular in shape and elongated in the tangential direction, the bordered pits

are smaller and fewer. Latewood tracheids are on the average about 10 % longer than ear-

lywood tracheids. In certain species (Douglas-fir, yew) the tracheids possess spiral thick-

enings – helical ridges on the inner faces of their walls.

Ray (horizontal) tracheids are very short cells in comparison to axial tracheids (length

0.1 – 0.2 mm) They have a general resemblance to parenchyma cells, but are different in

that they are empty, tend (especially the marginal ones) to attain more irregular shapes,

and possess small bordered pits. The inner walls of ray tracheids may be smooth, dentate

or reticulate.

Vessel members: Vessel members occur only

in hardwoods. In wood tissue a number of such

cells are connected endwise to form a pipe-like

structure which is called a vessel. The end

walls of the component vessel members disap-

pear wholly or partially in the process of devel-

opment after being formed by cambium. The

area of the adjacent end walls involved in end-

wise connection of two vessel members is

called perforation plate. Perforations may

besimple or multiple. Simple perforation is

a single, usually large, rounded opening. Multi-

ple perforation plates consist of several open-

ings, and when these openings are elongated,

parallel and separated by bars (remnants of cell

walls), the plates are called scalariform.

In cross-sections, vessels appear as solitary pores, or in multiples, chains,

or clusters. Their shape may be circular, ellipsoid or angular. A chain is made of adjacent

solitary pores arranged in line. A multiple is also made of adjacent pores, but these tend

to be flattened along the lines of contact, thus appearing as subdivisions of a single large

pore. In a cluster, several pores form an irregular group.

The size of vessel members varies widely. compared to tracheids, vessel members

are short (length 0.2 – 1.3 mm, diameter 0.005 – 0.5 mm). Vessel members have bor-

dered pits. The inner surface of their walls may possess spiral thickenings.

Tyloses: Vessels which are non-functional, mainly when sapwood is transformed to

heartwood, may be plugged with tyloses. Tylosis is an outgrowth from an adjoining ray

or vertical parenchyma cell through a pit-pair into the lumen of vessel. This is apparently

a result of differential pressure in the lumina of adjoining vessels and parenchyma cells.

Tylosis consists of protoplasm of the parenchyma cell and of storage materials in the

form of starch, crystals, resins, gums and others. Tyloses may also form pathologically,

as a result of mechanical injury, fungus, or virus infection.

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Vascular and vasicentric tracheids: Vascular and vasicentric tracheids are both rare

cell elements occurring only in a few hardwoods in association with vessels. Vascular

tracheids resemble small vessel members but have no perforated ends. They have many

bordered pits and may possess spiral thickenings. Vasicentric tracheids are mainly found

near the large early wood vessel in some ring-porous woods. They also have closed ends

and many bordered pits, but differ from vascular tracheids in that they are mostly longer

and irregular in shape.

Parenchyma: Parenchyma cells are typically prismatic (brick-like) cells and have simple

pits. According to orientation in the tree, parenchyma is classified as axial (vertical) pa-

renchyma and ray (radial) parenchyma.

Axial parenchyma is not present in all woods, in general, its more abundant in hard-

woods than in softwoods species. Parenchyma cells of softwoods may be diffuse among

the tracheids, banded (in tangential lines or bands) and boundary (initial or terminal, if

are placed at the boundaries of growth rings). Hardwood axial parenchyma, according to

its position relative to vessels, may be paratracheal (located adjacent to vessels)

and apotracheal (not in contact with vessels). In both softwoods and hardwoods, more

than one of the above types of axial parenchyma may be present in a growth ring.

Ray parenchyma cells constitute the rays wholly or in part. Rays in hardwoods are com-

posed entirely of ray parenchyma cells; however, in softwoods ray tracheids may also be

present, as may resin canals. Rays consisting of radially elongated parenchyma cells of

practically equal height are called homocellular (homogeneous). If certain rows (usually

the marginal) are made of squarish or upright cells, or if ray tracheids are present, the

rays are termed heterocellular (heterogeneous). Rays that include resin canals

are fusiform.

Rays may be uniseriate (one cell wide as seen in tangential view), biseriate, mul-

tiseriate and aggregate. In tangential sections or cross sections, aggregate rays are re-

vealed to be composed of several uniseriate and wider rays separated by rows of fibers

and sometimes by rows of small vessels. As a rule, rays of softwoods are uniseriate. in

hardwoods, rays of varying width may be present in the same species. In general, paren-

chyma cells are smaller than other cells, similar in size only to ray tracheids (length 0.1 –

0.22 mm, width 0.01 – 0.05 mm). Abnormal parenchyma cells may be produced as

a result of injuries to the cambium. Parenchyma has storage function in wood.

Figure: RLS of Pinus res-

inosa wood showing verti-

cal tracheids with bordered

pits.

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Fibers: Fibers are present only in hardwoods. they are long narrow cells with a general

resemblance to latewood tracheids (length 1 – 2 mm, diameters 0.01 – 0.05 mm). Fibers

have closed ends, mostly pointed and sometimes equipped with dentations. The walls

may be thick or thin, and lumina narrow or large. This varies mainly with species, but

fibers produced near the end of growing period are thick-walled and tangentially flat-

tened.

Fibers are classified into fiber tracheids and libriform fibers. Fiber tracheids have

borderd pids, while libriform fibers have simple (sometimes minutely bordered) pits. Li-

briform fibers are also usually smaller than fiber tracheids and have very narrow lumina.

The primary function of fibers is to provide mechanical support to the living tree; howev-

er, the (fiber tracheids, especially) may also participate in conduction. Some fibers

are septate( with thin transverse walls across the lumen).

Intercellular canals and spaces: Intercellular canals are spaces in wood tissue. They are

not cells. They are lined with specialized parenchyma cells called epithelial cells. Inter-

cellular canals may occur in both softwoods (resin canals) and hardwoods (gum canals).

Resin canals extend axially among vertical tracheids and radially within rays. In general,

axial canals have larger diameters than radial, but both are interconected and form

a network within the tree. Radial resin canals are contained in fusiform rays. Epithelial

cells may be thin-walled or thick-walled. Epithelial cells are considered the source of res-

in.

Wounding of the cambium leads to formation of traumatic canals, which differ from nor-

mal resin canals in structure and arrangement.

When sapwood transform into heartwood, resin canals may become plugged

with tylosoids. This phenomenon is analogous to the formation of tyloses in hardwoods,

but differs in that a tylosoid

deriver from an epithelial

cell and does not pass

through a pit cavity.

Gum canals may be axial or

radial, but both types sel-

dom occur in the same

wood. Gum canals may be

normal or traumatic. Normal

canals do not appear in tem-

perate woods of commercial

importance.

Intercellular spaces, not

canals, sometimes exist

when adjacent cell contact is

not tight. Such spaces are

characteristic of compres-

sion wood in softwoods.

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SAMPLES OF MACERATED WOODS

Pinus - Wood maceration (Trachedis only)

A macera-

tion of the

wood of

Hedera helix

(Climber)

shows two

vasicentric

tracheids

(vertical) as

well as a

number of

libriform

fibers.

Oak - Wood - Macerated xylem elements showing tracheids, fibres and vessels

Xylem vessel

elements of a

Cucurbit

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SCIENTIFIC/BOTANICAL DESCRIPTION OF A WOOD :

(a) General features: These include features which can be directly observed without the

aid of a microscope. The major general features include:

1. Colour, 2. Hardness, 3. Weight, 4. Odour, 5. Lustre, 6. Texture , 7. Grain.

(b) Anatomical features: Transverse (TS), radial longitudinal (RLS) and tangential lon-

gitudinal sections (TLS) will give general anatomical features of the wood. Maceration of

fibres and vessels will be useful for recording the cellular dimensions and anatomical fea-

tures such as the arrangement, distribution, frequency and size of the various cell ele-

ments viz., vessel, axial parenchyma, ray parenchyma and fibres in the wood.

Each timer is described in the following manner:

Colour: Generally referred to heartwood only unless noted otherwise as heartwood and

sapwood.

Weight (Specific gravity): Depending on weight, in air-dry condition, timber is classi

fied as:

A. Very light and light (Specific gravity up to 0.55)

B. Moderately heavy (Specific gravity up to 0.55-0.75)

C. Heavy and very heavy (Specific gravity above 0.75)

Texture:

A. Fine (Smooth to feel)

B. Medium (Fairly smooth to feel)

C. Coarse (Rough to feel)

Strength group:

A. Weak (Compression parallel to grain up to 28N/mm2

B. Moderately strong (compression parallel to grain: 28-41 N/mm2

C. Strong and very strong (Compression parallel to grain; above 41N/mm2

Durability: Life span in years (as determined by graveyard tests)

A. Perishable (Less than 5 years,

B. Moderately durable (5-10 years),

C. Durable ( 10-25 years),

D. Very durable (above 25 years)

Treatability: Ability of the timber to preservative treatment:

A. Easy (Timbers that can be penetrated with preservatives completely under

pressure without difficulty)

B. Moderately resistant (Timbers that are fairly easy to treat)

C. Resistant (Timbers that are difficult to impregnate under pressure)

D. Extremely resistant (Timbers that are refractory to treatment)

Hard woods Soft woods

Conifers (Gymnosperms)

Tracheids only

Texture homogenous

―Soft‖—easily split

Uses– building, paper

Not all are ―soft‖ woods

Angiosperms

Tracheids and vessels

Texture heterogenous

―Hard‖ wood

Uses– furniture, fuels

Not all are ―hard‖ woods if full of pores.

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ACACIA

General features: Acacia auriculiformis is moderately heavy wood. To identify the

wood, check the following:

Heartwood is dark brownish

Wood is moderately heavy

Parenchyma paratracheal and vasicentric

Rays fine, numerous and closely spaced.

Vessels solitary and in radial multiples of two to three.

Colour : Heartwood is light brown to dark red; clearly demarcated from the yellowish

\ white sapwood.

Weight : Moderately heavy (Air-dry specific gravity 0.60-0.75 with average values of

0.72)

Grain : Straight or wavy

Texture : Fine

Strength : Strong

Drying and shrinkage : Dries easily; shrinkage-radial (2%), tangential (4%),

volumetric (6%).

Durability : Moderately durable

Treatability : Moderately resistant.

Working properties : Planing-easy; boring-easy; turning-easy; nailing-satisfactory;

finish-good.

Trade Name Acacia

Vernacular Name Akasia (Indonesia); Australian Babul, Aus-

tralian wattle, Acacia, Kasia (India); Dar-

win Black wattle, Tan wattle (Australia)

Botanical Name Acacia auriculiformis A. Cunn. ex Benth.

Family Name Leguminosae (Fabaceae)

Origin (Distribution) An exotic. Native to Papua New Guinea

(PNG), Australia and Solomon Islands; in-

troduced into many tropical countries as a

fast growing species for pulp wood.

Tree A medium sized tree reaching about 20m in

height and 90cm in diameter. The species

has become naturalized in many parts of

India including Kerala.

Compression parallel to

grain

Static bending

Modulus of Rupture

(MOR) N/mm2

Modulus of Elasticity

(MOE) N/mm2

Maximum Crushing Stress

(MCS) N/mm2

74 10531 45.0

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Gross features:

Growth rings fairly distinct. Diffuse porous wood.

Vessels: Solitary and in radial multiples of two to three, large to medium sized and

moderately numerous (15-24/mm2). Soft tissue forms sheaths around vessels.

Rays fine, numerous and closely spaced; one to three cell wide, homogenous, wholly

made up of procumbent cells.

Parenchyma paratracheal and vasicentric.

Uses: Used for furniture making and construction purposes. Mainly used for pulp wood

production. Suitable for door and window shutters, light construction, furniture, flooring,

industrial and domestic woodware, tool handles, turnery articles, carom coins, agricultur-

al implements, charcoal etc.

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MANGO

General features: Mangifera indica (Mango wood) is a moderately hard and heavy

wood. It has yellowish white to grayish brown and somewhat lustrous wood. To identify

the wood, check the following:

Growth rings are fairly distinct

Wood is moderately hard and heavy

Aliform to confluent parenchyma and often delimiting growth rings

Rays are fine to moderately broad and numerous

Vessels are large to medium often filled with tyloses, numerous and solitary or in ra-

dial multiples of 2-3.

Colour : Yellowish white to grayish brown, sap wood and heart wood not distinct or

sometimes heartwood distinct and dark brown; somewhat lustrous.

Weight : Moderately hard and moderately heavy, 690 kg/m3 at 12% m.c

Grain : Straight to somewhat interlocked

Texture : Medium to coarse

Strength : Strong

Trade Name Mango wood

Vernacular Name Maavu, moochi (Mal), Aaam (Hin.)

Botanical Name Mangifera indica L.

Family Name Anacardiaceae

Origin (Distribution) West coast tropical evergreen and West

coast semi evergreen forests; cultivated ex-

tensively.

Tree Medium to large 15-30m in height and 50-

100cm in diameter. Bark brown or dark

grey, rough.

Compression parallel to

grain

Static bending

Modulus of Rupture

(MOR) kg/cm2

Modulus of Elasticity

(MOR) kg/cm2

Maximum Crushing Stress

(MOR) kg/cm2

904 111,800 448

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Drying and shrinkage: Not refractory; green conversion followed by stacking in dry

ventilated area recommended. Kiln-seasoning improves the appearance of the timber

without degradation. Retains its shape remarkably well seasoning. Shrinkage green to

oven dry radial (3.2%); Tangential (4%).

Durability: Non - durable

Treatability: Easily treatable

Working properties: Easy to saw, machining satisfactory, good polish. Nail and screw

holding capacity excellent. Peals well.

Gross features:

Wood is diffuse porous.

Growth rings fairly distinct.

Vessels large to medium, few to moderately numerous, solitary or in radial multiples

of 2-3 or more, often filled with tyloses.

Parenchyma paratracheal– aliform to confluent, often delimiting growth rings.

Rays fine to moderately broad, numerous, closely spaced.

Pith flecks are usually present.

Uses: Ceiling boards, window frames, general purpose class I plywood, furniture and

cabinets, black boards, match splints and boxes, boat and ship buildings, bobbins, bent

wood articles, shoe-lasts.

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Trade Name Neem

Vernacular Name Aryaveppu, Veppu, Vempu, Leemdo, Ka-

dunimb, Neem (India), Nim (Pakistan),

Baypay (Malaysia), Kwinin (Thailand),

Mindi (Indonesia).

Botanical Name Azadirachta indica A. Juss.

Family Name Meliaceae

Origin (Distribution) Native of Indian subcontinent; distributed

throughout South-East Asia, East and Sub–

Saharan Africa, Fiji and some parts of Cen-

tral America. Naturally found in deciduous

forests of Peninsular India and homesteads

of Kerala.

Tree Medium to large tree with a height of 15-

20m with a clear bole of 7 m and diameter

of 50cm.

General features:

Azadirachta indica A. Juss (Neem ) is moderately heavy wood. To identify the wood,

check the following:

Heartwood is reddish brown, aromatic and slightly lustrous

Distinct growth rings

Parenchyma: Apotracheal, paratracheal, vasicentric, also in tangential lines connect-

ing vessels.

Vessels medium sized, few and occurring in solitary or in radial multiples of two to

three, often in clusters and filled with reddish gummy deposits.

Colour: Heartwood reddish brown, aromatic; moderately lustrous. Sapwood is yellowish

white, yellowish brown or grayish yellow.

Weight: Hard to moderately hard; moderately heavy, (835 kg/m3 at 12% m.c)

Grain: Interlocked

Texture: Coarse

Strength: Strong

Compression parallel to

grain

Static bending

Modulus of Rupture

(MOR) kg/mm2

Modulus of Elasticity

(MOR) kg/mm2

Maximum Crushing Stress

(MOR) kg/mm2

89 9666 47.1

NEEM

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Drying and shrinkage: Dries well, Green conversion followed by open stacking under

cover recommended; shrinkage-green to oven dry; Radial (4.5%), Tangential (6.2%)

volumentric (10.7%)

Durability: Durable, resistant to termite damage.

Treatability: Resistant

Working properties: Planing-easy, boring– easy, Turning—easy, Nailing-good, but pre-

boiling necessary; Finish-good. Sawing and machining fairly good, gives fair finish.

Gross features:

Growth rings distinct.

Vessels medium, few to moderately few, solitary radial multiples of two to three, of-

ten in clusters; numerous (16-20/mm2). Vessels filled with reddish gummy deposits.

Soft tissue forms bands delimiting growth ring and also associated with vessels.

Parenchyma– Apotracheal-irregularly placed tangential and continuous bands delimit-

ing growth rings. Paratracheal. Vasicentric, also in tangential lines connecting vessels.

Rays fine to medium sized, numerous and somewhat widely spaced.

Special features: The wood possesses characteristic odor. The wood has insect repellant

properties due to the presence of neem oil. Gum canals often present in tangential bands.

Uses: Used in light construction, furniture, doors and window frames boards and panels,

cabinets, boxes and crates. Also used for agricultural implements, tool handles, musical

instruments, cigar boxes, matches, ply wood, veneers, carving, and toys.

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General features:

Pterocarpus santalinus L.f (Red sanders) is a heavy wood. To identify the wood, check

the following:

Heartwood dark orange red with darker streaks when freshly cut, turning deep red to

purplish black on exposure.

Wood is hard to very hard, very heavy

Parenchyma paratracheal, alisform and narrow aliform confluent but also forms nar-

row confluent wavy bands, also marginal and as diffuse scattered cells, stands storied.

Rays fine to very fine, somewhat closely spaced, and uniformly distributed.

Vessels moderately large to small, just visible to eye, few to moderately few (3-12

per mm2), solitary or in radial multiples of two to three, frequently filled with reddish

brown gummy deposits.

Colour: Heartwood and sapwood clearly demarcated. Sapwood yellowish white, heart-

wood dark orange red with darker streaks when freshly cut, turning deep red to purplish

black on exposure.

Weight: Wood is hard to very hard, very heavy (1120kg/m3 at 12m.c

Grain: Interlocked to wavy grain.

Texture: Medium-fine.

Strength: Extremely strong

Trade Name Red sanders

Vernacular Name Yerra chandanam, yerra sandanam (Tel.);

chemmaram, sevapu chamdrium (Tam.); Rak-

tha chandanam (Mal.); Lal chandan, (Hindi);

Kempu gandha, rakta chandana (Kan.).

Botanical Name Pterocarpus santalinus L.f.

Family Name Leguminosae (Fabaceae)

Origin (Distribution) Southern most mixed deciduous forest, moist

teak bearing forest, west coast semi-evergreen

and souther dry mixed deciduous forests. It

occurs gregariously on the dry hill slopes of the

Eastern Ghats. Endemic to Andhra Pradesh and

Tamil Nadu.

Tree A moderate sized tree, up to 10m in height with

a clear bole of 4.5-6 m and 35cm in diameter;

1m in girth but may attain 1.5m in girth. Bark

dark dirty-brown, rough with deep vertical and

horizontal cracks.

RED SANDERS

Compression parallel to grain

Static bending

Modulus of Rupture (MOR) kg/cm2

(air dry)

Modulus of Elasticity (MOR) kg/cm2

(air dry)

Maximum Crushing Stress (MOR) kg/cm2

(air dry)

NA NA 345

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Drying and shrinkage: Seasons well; Radial 2%; Tangential 6%; Volumetric 8 %.

Durability: Very durable.

Treatability: It does not need preservative treatment

Working properties: It is difficult to saw and work, but can be turned and carved exceptionally

well. It works fairly well with hand-tools.

Gross features:

Growth rings are indistinct or barely visible even under the hand lens. Diffuse porous

wood.

Vessels moderately large to small, just visible to eye, few to moderately few (3-12 /

mm2). Solitary or in radial multiples of two to three, frequently filled with reddish

brown gummy deposits. Soft tissue narrow, broken to fairly continuous bands often

connecting the vessels, sometimes appearing as aliform with fine short or long lateral

extensions and also a fine interrupted line delimiting growth rings.

Rays fine to very fine. Somewhat closely spaced, and uniformly distributed. Ripple

marks are present, distinct in the sap wood under hand lens but usually inconspicuous

in heartwood.

Parenchyma aliform and narrow aliform confluent but also forms narrow confluent

wavy bands, also marginal and diffuse scattered cells, strands storied and fusiform.

Uses: It is used to make musical instruments especially ―shamisen‖, carving idols, toys,

ornamental house-posts and planks. It is generally used for agricultural implements,

sports goods, tool handles, verandah pillars, bent rims in cart construction and picture

frames. Its powder and chips are used for the manufacture of dyes and medicines and is

reported to be exported.

Andaman Padauk Scientific Name: Pterocarpus dalbergioides

Distribution: Andaman Islands

Tree Size: 80-120 ft (24-37 m) tall, 2-4 ft (.6-1.2 m) trunk diameter

Average Dried Weight: 48 lbs/ft3 (770 kg/m3)

Specific Gravity (Basic, 12% MC): .63, .77

Janka Hardness: 1,630 lbf (7,250 N)

Modulus of Rupture: 14,770 lbf/in2 (101.9 MPa)

Elastic Modulus: 1,754,000 lbf/in2 (12.10 GPa)

Crushing Strength: 8,830 lbf/in2 (60.9 MPa)

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TEAK

General features:

Tectona grandis (teak) has golden bown heart wood with black streaks. However, wide

variation in colour is present between teak available from different regions. The heart-

wood has an oily feel with a distinct smell resembling old leather. Teak is atypical ring

porous hard wood. The early wood vessels are large and few, compared to the late wood

vessels which are small and numerous. To identify the wood, check the following.

Wood is moderately hard and moderately heavy.

Parenchyma is paratracheal (Vasicentric and broad bands); distinct to the eye in the

early wood, forming a continuous zone enclosing the vessel along with initial band of

parenchyma delimiting growth.

Vessels are filed.

Colour: Sapwood and heartwood sharply demarcated. Heartwood golden brown when

fresh or dark brown on exposure occasionally with black streaks with a waxy feel, lus-

trous sometimes with white glistening deposit, distinct aromatic odour with the smell of

leather. Sapwood white, pale yellow or grey. Well defined.

Weight: Moderately hard and moderately heavy (650Kg/m3 at 12% m.c).

Grain: Straight, sometimes wavy.

Texture: Coarse

Trade Name Teak

Vernacular Name Jati, Tek (Indonesia), Java teak (Germany),

Kyun (Myanmar), Teca (Brazil), Segan

(Beng), saga, sagach (Guj.), sagon, sagwan

(Hindi), Tega (Kan.), Sag, saga (Mar.), Sin-

gua (Or.), Tekku, Tekkumaram (Tam.),

Adaviteeku, Peedateeku (Tel.)

Botanical Name Tectona grandis Linn.f.

Family Name Verbenaceae

Origin (Distribution) It is a deciduous tree with rounded crown

which under favourable conditions attains

large size with a clean cylindrical bole of-

ten becoming buttressed and fluted.

Tree Towards the base. The tree is large to very

large, 25-45m in height and up to 190cm in

diameter, but in the dry hot areas of Madh-

ya Pradesh, Gujarat and Rajasthan the tree

is comparatively smaller, often branchy and

much fluted in advanced age. Bark light

brown or grey with shallow longitudinal

furrows and fibrous, about 0.4-1.8cm thick,

exfoliating in long thick strips.

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Drying and Shrinkage: Dries well but rather slowly with little or no degradation. Sea-

sons very well, the best model wood for air seasoning; kiln seasoning also good for very

good results. Shrinkage radial (2.3%), tangential (4.8%), volumetric (7.1%). Highly re-

sistance to water absorption.

Durability: Very durable, highly resistant to termite damage.

Treatability: Extremely resistant; heart wood very refractory to treatment.

Working properties: Easily worked with both hand and machine tools. Planing easy,

boring easy, turning-rather easy, nailing –good but pre-boiling necessary, finish good.

Gross features:

Growth rings are distinct, delim-

ited with early wood vessels en-

closed in parenchymatous tissues,

less than 1-6/cm. Vessels large in

early wood, oval in out line, occa-

sionally filled with tyloses and yel-

lowish-white powdery deposits.

Vessels medium to small in late

wood, mostly solitary or in short

radial multiples, round to oval in out line, vessel lines of the early wood zone conspicu-

ous on longitudinal surfaces.

Parenchyma paratracheal-vasicentric and in broad bands, distinct under the hand lens but

distinct to the eye in the early wood forming a continuous zone enclosing the vessel

along with initial band of parenchyma delimiting growth rings.

Rays moderately broad, fairly wide spaced and uniformly distributed; visible to the eye,

distinct under lens.

Uses: A versatile wood. Used extensively for ship and boat building, class I general pur-

pose plywood, cabinet making, interior and exterior joinery, flooring and fine furniture,

carving, paneling, turnery, sliced for decorative and face veneers. Teak laboratory fittings

and laboratory accessories are logical choice due to the acid and alkalis resistant proper-

ties of this timber, it is also used for vats, towers etc. in chemical plants. Building con-

struction poles and cross arms, textile mill accessories, musical instruments, mathemati-

cal, engineering and drawing instruments and bus bodies. It is used for doors and win-

dows in house construction, paneling and interior fittings. It is also used for air crafts,

marine plywood and block boards. It is an approved timber for table tennis tables, frame

of carom boards and general requirements of play ground and park equipment, wooden

butter-scoop, butter moulds, wooden boxes for microscopic slides, stand for ammunition

explosive boxes and caulking mallets. Teak poles are used for scaffolding, fence posts

and for overhead and telecommunication lines.

Compression parallel to

grain

Static bending

Modulus of Rupture

(MOR) kg/mm2

Modulus of Elasticity

(MOR) kg/mm2

Maximum Crushing Stress

(MOR) kg/mm2

106 10000 60.4

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RUBBER

General features:

Hevea braziliensis (HBK) Muell. Arg. (Rubber) is a soft and light timber. To identify the

wood, check the following:

Wood is white to creamy in colour.

• Wood is light to moderately heavy

• Parenchyma: abundant, apotracheal-diffuse, tangential wavy lines and also in more or

less continuous fine line delimiting growth rings, paratracheal- vasicentric.

• Rays fine, somewhat closely spaced.

• Vessels medium to small moderately numerous to few, solitary or in radial multiples of

3 or 4, occasionally with tyloses and white to chalky deposits.

Colour: Heartwood and sapwood are not distinct. Wood is white to creamy in colour

when freshly cut, sometimes with a pinkish ting, turns to light brown or creamy white on

exposure.

Weight: Light to moderately heavy; (525-610 kg/m³ at 12% m. c).

Grain: Straight

Texture: Even and medium textured

Strength: Moderately strong

Trade Name Rubber

Vernacular Name Rubber tree

Botanical Name Hevea braziliensis (HBK) Muell. Arg

Family Name Euphorbiaceae

Origin (Distribution) Native of Brazil; raised extensively in plan-

tations in Malaysia, Indonesia, Thailand,

Sri Lanka and India for latex production.

Tree Large tree reaching a height of 30m and

diameter of 40-70 cm, bark greyish-black,

smooth.

Compression parallel to grain

Static bending

Modulus of Rupture (MOR) kg/cm2

(air dry)

Modulus of Elasticity (MOR) kg/cm2

(air dry)

Maximum Crushing Stress (MOR) kg/cm2

(air dry)

66 9240 32.3

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Drying and Shrinkage: Dries easily; but care is needed to avoid seasoning defects such

as cupping, twisting, bowing, checking and splitting; a conventional kiln seasoning

(steam- heated, forced-air drying system) is preferred in drying, shrinkage-radial (1.2%),

tangential (1.8%), volumetric (3.0%).

Durability: Perishable, the wood has to be treated with preservatives soon after felling

(preferably with for 48 hrs.) liable to discolouration caused by sap stain fungi and attack

by pinhole and powder post beetles.

Treatability: Easy. Simple dip treatment or vacuum- pressure impregnation process with

preservatives such as borax-boric acid and copperchrome arsenate (CCA) with adequate

retention will protect the wood from fungal and insect attack.

Working Properties: Planing-easy; boring-easy; Turning-easy; Nailing-good, but pre-

boring necessary; Finish-good. Tension wood can lead to fuzzy grain when machined.

Finger jointing is often applied to achieve larger dimensions. Rubber wood can be stream

bent with good results. It can easily be stained to resemble teak, rosewood, walnut, cher-

ry, oak or other woods, depending on consumer demand.

Gross features:

Growth rings indistinct, but sometimes appearing as faint impressions due to

comparatively thick walled fibrous tissues.Diffuse porous wood.

Vessels medium to small moderately numerous to few, solitary or in radial

multiples of 3 or 4, occasionally with tyloses and white to chalky deposits,

oval in outline.

Parenchyma abundant, apotracheal- diffuse, tangential wavy lines, touching

the vessels and also in more or less continuous fine line delimiting growth

rings, paratracheal- vasicentric.

Rays fine, light in colour uniformly distributed and somewhat closely spaced.

Uses: Used for the manufacture of furniture (dining sets, bedroom sets, lounge sets, rock-

ing chairs) and furniture parts, bentwood furniture , second grade door furniture, dunnage

pallets, parquet and strip flooring, paneling, wood based panels particle board, cement

and gypsum- bonded, medium-density fibre board, packing cases, match splints and box-

es etc. Traditionally it is used for fuel wood and industrial brick burning.

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BANYAN

General features:

Ficus bengalensis L. (Banyan) is light to moderately heavy wood. To identify the wood,

check the following:

• Creamy white to greyish white when first exposed turning grey or pale brownish grey

with age, discolours rapidly by sap stain.

• Wood is light to moderately heavy

• Parenchyma abundant, visible to the eye, forming more or less concentric narrow or

broad bands alternating with fibrous tissue: 4-20 per 5mm.

• Rays moderately broad to broad, distinct to the eye, widely spaced, forming inconspicu-

ous to conspicuous flecks on radial surface.

Colour: Creamy white to greyish white when first exposed turning grey or pale brown-

ish grey with age, discolours rapidly by sap stain; heartwood and sapwood not distinct.

Weight: Light to moderately heavy. Air- dry specific gravity approx. 0.61

Grain: Shallowly interlocked.

Texture: Coarse and uneven.

Strength: Weak

Drying and Shrinkage: Dries easily; liable to warp. Shrinkage data not available.

Durability: Perishable. Timber is not durable in exposed condition but quite durable in

dry places and under cover.

Treatability: Easy.

Working Properties: Sawing- easy; mottling figure may be obtained by flat sawing.

Trade Name Banyan

Vernacular Name Peepal, Peral, Banyan (India), Bor (Asm.),

Vad, Vor (Guj.), Bar, Bargad (Hind.), Alada

(Kan.), Vata (San.), Ala, Alai (Tam.), Marri

(Tel.), Aal, Peral (Mal.)

Botanical Name Ficus bengalensis L.

Family Name Moraceae

Origin (Distribution) Asia-through out the forest tracts of India, both

in sub-Himalayan region and in deciduous for-

ests of Deccan and other parts of South India.

Tree Large tree with spreading branches attaining a

height of 30 m. Bark greyish white, smooth.

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Gross features:

Diffuse porous wood. Growth rings inconspicuous.

Vessels large to small distinct under the hand lens, Solitary or in radial multi-

ples of 2-4, few to moderately numerous (5-15 per mm2), more or less evenly

distributed, open or often plugged with tyloses, vessel lines distinct.

Parenchyma abundant, visible to the eye, forming more or less concentric nar-

row or broad bands alternating with fibrous tissue: 4-20 per 5mm.

Rays moderately broad to broad, distinct to the eye, widely spaced, forming

inconspicuous to conspicuous flecks on radial surface.

Uses: Third class wood used for making tea boxes,

toys and for light packing cases. The wood of aerial

roots can be used for tent poles, cart yokes and carrying shafts. The timber is used for

making well-curbs, furniture, crates, door panels and cart-shafts. The props are used for

tent poles and umbrella handles.

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STOMATAL TYPES IN ANGIOSPERMS

Aim: To study the stomatal types of different species of Angiosperms.

Theoretical background: Stomata are minute pores which occur on epidermal surface

of leaves and also on some herbaceous stems. Each stoma is guarded by two specialized

epidermal cells, called guard cells which are surrounded by other specialized epidermal

cells called subsidiary cells or accessory cells. The members of Angiosperms differ in the

number and arrangement of subsidiary cells around the guard cells. Closely related spe-

cies in a family have the same type of stomata and thus the stomatal type is also useful in

taxonomy.

Requirements: Leaves of different species of Malvaceae, Solanaceae, Rubiaceae, Acan-

thaceae, Araceae/Musaceae/Commelinaceae, Palmae/Pandanus, Cyclanthaceae, Poace-

ae/Cyperaceae. Microscope, microslides, coverglass, Safranin.

Procedure: Take the leaves from each species; cut into small rectangular pieces of 0.5 x

1 cm size. Peel of the upper / lower epidermis. Make a temporary mount on microslides.

Observe under microscope. Note the number and arrangement of subsidiary cells and

identify the type of stomata based on the classification by Metcalfe and Chalk (1950).

Stomata of a leaf peel under low power Stomata of a leaf peal under high power

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STOMATAL TYPES IN ANGIOSPERMS

Metcalfe and Chalk (1950) classified the

stomata as follows:

1. Anomocytic (irregular celled) or Ra-

nunculaceous: In this type, the stomata

remains surrounded by limited number of

subsidiary cells which are quite alike the

remaining epidermal cells.

Example: Ranunculaceae, Malvaceae,

Papaveraceae

2. Anisocytic (Unequal celled) or Cru-

ciferous: In this stomata remains surrounded by three subsidiary cells of which one is

distinctly smaller than the other two.

Example: Cruciferaceae, Solanum, Nicotiana etc.

3. Paracytic (Parellel celled) or Rubiaceous: In this type, the stomata surrounded by

two subsidiary cells which are parallel to the longitudinal axis of pore and guard cells.

Example: Rubiaceae

4. Diacytic (Cross celled) or Caryophyllaceous: In this type, the stomata remains sur-

rounded by a pair of subsidiary cells whose common wall is at right angles to the guard

cells.

Example: Acanthaceae, Caryophyllaceae.

5. Actinocytic: These stomata are surrounded by four or more subsidiary cells, elongated

radially to the stomata.

Example: Araceae, Musaceae, Commelinaceae.

6. Cyclocytic: The stomata are surrounded by four or more subsidiary cells arranged in a

narrow ring around the stoma.

Example: Palmae, Pandanus, Cyclanthaceae.

7. Graminaceous

type: The sto-

matal guard cells

are dumb bell

shaped. They are

surrounded by

subsidiary cells

which are lying

parallel to the

long axis of the

pore.

Example: In the

members of Po-

aceae and Cyper-

aceae.

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Paracytic stomata in:

A. Cynodon dactylon, B - D. Chloris barbata - Leaf (B), glume (C), anther (D),

E– Desmostachya bipinnata, F - H - Dichanthium annulatum: Leaf (F), gluem (G), anther (H)

I– Cymbopogon citrates, J– Sorghum helepense

K– M– Arundo donax - Leaf (K), anther (L), glume (M)

N– Cenchrus ciliaris, note bicellular trichome.

Inamdar, J. A. 1970. Epidermal structure and development of stomata in some Gra-

mineae. Bulletin de la Société Botanique de France, 117: 385-394.

STOMATA IN SELECTED GRASSES

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STOMATA IN SELECTED GRASSES

Paracytic stomata in:

A– Eleusine coracana, B– Dactylocteium aegyptium, C– Eragrostis unioloides, D– Paspalum scrobicula-

tum, net bicellular trichome, E– Bracharia setigera, note Uni– and bicellular trichomes and Ca-oxalate

crystals, F– Apluda mutica, G– Saccharum spontaneum, H– Sorghum vulgare, I– Echinochloa colonum, J–

Setaria verticillata, K– Unicellular trichome, L. Dendrocalamum strictus (young leaf sheath), M– Oryza

sativa, N– conical trichome from the margin of the leaf—Triticum aestivum, O-Coleoptile, P– Leaf

(young), Q– Digitaria adscendens, R-Porotis indica, S. Heteropogon contortus.

Inamdar, J. A. 1970. Epidermal structure and development of stomata in some Gramine-

ae. Bulletin de la Société Botanique de France, 117: 385-394.

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STOMATA OF CUCURBITS

Leaf surface view of :

(a) Coccinia barteri showing actinocytic stoma, (b) Coccinia grandis showing actinocyt-

ic stoma, (c) Citrullus lanatus showing anisocytic stoma, (d) Citrullus colocyn-

this showing diacytic and cyclocytic stomata, (e) adaxial, (f) abaxial, Cucumis me-

lo anisocytic stoma, (g) Cucumis sativus showing paracytic stoma, (h) Lagenaria brevi-

florus showing diacytic and paracytic stomata, (i) adaxial, (j) abaxial), Lagenaria sicerar-

ia showing staurocytic and paracytic stomata, (k) adaxial, (l) abaxial), Luffa acutangu-

la actinocytic stoma, (m) Luffa cylindrica showing actinocytic and staurocytic stomatam,

(n) adaxial, (o) abaxial, Momordica charantiashowing diacytic stoma, (p) Momordica

foetida showing actinocytic stoma, (q) Telfairia occidentalis paracytic stoma and

(r) Trichosanthes cucumerina showing diacytic stoma.

“Diagnostic Significance of Leaf Epidermal Features in the Family Cucurbitaceae‖

by A.A. Abdulrahaman, R.A. Oyedotu, F.A. Oladele, in Insight Botany, 1: 22-27.

http://docsdrive.com/images/insightknowledge/BOTANY-IK/2011/fig1-2k11-22-27.gif

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Stomatal types: A1, Anomocytic; A (2,3,4), Staurocytic; B, actinocytic; C, (1,2), cy-

clocytic; C (3,4), tetracytic; D, amphicyclocytic, E, (1,2,3), anisocytic; E4, amphianiso-

cytic; F, helicocytic; G, (1,2,3), diacytic; H, (1,2), amphianisocytic; I, (1,2), laterocyclic;

I3, paracytic; J, (1,2), amphiparacytic; K, bracyparacytic; L, (1,2), amphibracyparacytic;

M, hemiparacytic; N, paratetracytic; O, amhiparatetracytic; P, brachuparatetracytic; Q,

amphibrachyparatetracytic, R (1,2,3) parahexacytic-monopolar; R4, parahexacytic-

dipolar.(Photo credit: Science Alert).

Stomata in Dicots

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ERGASTIC SUBSTANCES

A.

FOOD PRODUCTS B.

SECRETORY

PRODUCTS

C.

WASTE PRODUCTS

Non-Nitrogenous Nitrogenous Fats &

fatty

acids

ENZYMES PIGMENTS NECTAR

Non-Nitrogenous Nitrogenous

Starch Inulin Hemicellulose Cellulose Sugars

Proteins Amino

compounds

Tannin Mineral crystal Latex Essential oils Gums

Alkaloids

CELL INCLUSIONS (ERGASTIC SUBSTANCES)

Ergastic substances or cell inclusions are:

The products of cell metabolism,

Appearing and disappearing at various stages of cell‘s life-cycle

Mostly waste products of simple chemical nature.

Present in the cell walls or vacuoles or in the organelles of protoplasm.

Present in soluble or insoluble state and

Organic or inorganic in nature.

These substances belong to three categories: I. Reserve food,

II. Secretory products

III. Excretory /waste products.

I. Reserve food: They occur in the form of starch, fat droplets and aleurone grains.

Carbohydrates: A. Starch grains: Starch is the most important storage food. Starch grains are found in all parts

of the plant although in storage organs, e.g., seeds, fruits, rhizome etc., these are found in larger

amount. Starch grains are of different shapes and form. Each starch grain has a central proteina-

ceous area called helium. Starch is deposited around it in the form of eccentric or concentric lay-

ers. The starch grains are oval eccentric in potato; oval and concentric in gram or pea; rounded,

flat and concentric in wheat and polyhedral with radiating lines in maize.

Figures A-F: Different types of starch grains: A. Simple eccentric starch grain of potato, B. Concentric starch grain of wheat, C. Concentric starch grain of maize, D. Com-pound starch grain of banana, E. Semicom-pound starch grain of potato, F. Compound starch grain of oat.

Starch grains in: A. Outer pericarp of Musa,

B. Cotyledon of Pisum, C. ray cell of Phloem

of Ailanthus, D. Cotyledon of Phaseolus.

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B. Inulin: Inulin has been reported from the roots of

many Compositae. It is commonly found in the tuberous

roots of Dahlia and Helianthus tuberosus. It can easily

be precipitated by keeping the Dahlia roots for 6-7 days,

in alcohol, in the form of spherical, star- shaped or wheel

-shaped crystals.

C. Hemicellulose: In some seeds food is stored in thick-

ened cell walls in the form of hemicellulose. Food is

stored in this form, however, much more rarely than as

sugar or starch. Hemicellulose (reserve cellulose) is

found in some palm seeds and also in the seeds of some

other plants.

D. Cellulose: This is a carbohydrate with a general for-

mula similar to that of starch, i.e., (C6H10O5)n. However,

the atoms are arranged differently in the molecule, and

starch and cellulose have very different properties. In the

plant, cellulose is made from sugars. It serves as building

material in the formation of the cell wall.

Fats: In plants fat droplets or globules occur abundantly

inside the seeds either in endosperm (e.g., castor, coco-

nut) or cotyledons [e.g., groundnut, mustard].

Proteins - Aleurone Grains: They are insoluble stor-

age proteins occur inside special leucoplasts called aleu-

roplasts. They occur in the outer endosperm cells of cere-

als, such as wheat, rice, maize grains.

Sphaerocrystals of inulin in

cells of Dahlia root.

Thickened walls of hemicelluloses

from Areca seed.

A. Aleurone grains in the endosperm

of castor seed,

B. Few grains magnified containing

crystalloids and globoids in them.

Aleurone grains. A. Wheat, B. Maize, C. Castor

Cells of endosperm

of coconut.

The large globules

are oil and the

small granules are

protein.

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II. Secretary products: Enzymes, pigments and nectars.

(i) Enzymes: Enzymatic proteins occur in colloidal state in the protoplasm.

(ii) Pigments: Various kinds of pigments like chlorophylls, xanthophylls, carotenoids,

anthocyanins etc are present in plants for various purposes. They are present in plastids.

(iii) Nectar: Nectar, secreted by nec-

taries in plants, attracts insects for pol-

lination because it is sweet and con-

tains sucrose, glucose and fructose.

The nectaries occur on flowers (floral

nectaries) and on vegetative parts

(extra floral nectaries). The floral nec-

taries are found in various positions

on the flower, whereas the extra floral

nectaries occur on stems, leaves, stip-

ules and pedicels of flowers.

Figures A & B. Nectary. A. Section of

surface of nectar of Euphorbia pulcher-

rima, B. Section of floral nectar of Malus

pumila.

III. Excretory /waste products:

Several chemical substances

which are of no use to plants are pro-

duced during metabolic reactions.

These waste products are called excre-

tory products, but the plants do not

have any special mechanism to re-

move these substances and are found

as cell inclusions.

1. Non-nitrogenous waste prod-

ucts:They are tannins, mineral crys-

tals, latex, essential oils, gums, resins,

and organic acids. They are either

found in the cytoplasm or in the cell-

sap.

(a) Tannins: They are non- nitroge-

nous complex compounds, commonly

found dissolved in the cell- sap. They

are the derivatives of phenol and usu-

ally related to glucosides. They are

found in the cell walls, in the dead

cells, in the heart wood and in the

bark.

Figures A-C. Tannin and crystals in

phloem parenchyma of Pinus (A),

Ray cells of wood of Malus pumila

(B). Pith cells of Fragaria.(C).

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b) Inorganic Materials

(Mineral Matter): The ac-

cumulation of inorganic ma-

terials within the plant and

their cells mostly takes place

in the form of calcium salts

or anhydrous silicate salts.

Calcium oxalate is common

in plants of many families.

Their crystalline particles are

of various shapes such as

prismatic, needle-shaped,

rhomboidal (diamond-

shaped) etc. Very often the

crystals occur as compound

aggregates called druses, sphaerites etc. Elongat-

ed crystals are called styloids and raphides.

Raphides occur in the form of bundles. Some

crystals occur in special type of cells such as in

case of idioblast cells.

Crystals of calcium carbonate are also found

in some plants. Well known example is the cys-

tolith found in some plants (e.g., Ficus leaves).

Leaves of Ficus species have cystoliths in their

epidermal cells.

Figure: Cystolith (Calcium carbonate) in leaf of Ficus

elastica (India rubber).

Figures A-D: Crystals: A. Druse with organic centre,

in phloem parenchyma cell of Juglans nigar; B. Vari-

ous forms of crystals in phloem parenchyma of Malus

pumila; C. Rhombohedral crystals in phloem paren-

chyma of Salix nigra; D. L. S of crystal in phloem

parenchyma of Tilia americana.

A B C

Raphides (Calcium oxalate needle like crystals): A.

From leaf of Colocassia, B. From leaf of Pistia. C.

Ejection of raphids from sac like cell of leaf of Colo-

casia.

Cells with different types of crystals. A & B. Druses from the cells of

Gnetum gnemon, C. prismatic crystals from cell of Gnetum indicum, D. a

bundle of raphides in leaf cell of Vitis vinifera.

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(c) Latex:

It is a milky substance secreted by latex glands.

Robber secreted by the rubber tree Hevea brasili-

ensis is an important example.

(d) Essential oils:

These are volatile oils produced by special glint‘s

and cells. Aromain flowers, leaves and bark are

due to essential oils.

(e) Resins:

Produced by the oxidation of essential oils. These

are found in some special glands or canals either

alone or in combination with essential oils. These

are insoluble in water but soluble in ether and alco-

hol. These are used in the manufacture of paints

and varnishes.

(f) Gums:

Produced by the disintegration of cellulose cell

wall. They are soluble in water. Used for sticking

purposes, and also as medicine,

(g) Organic Acids:

These are found in leaves

and fruits. Tartaric acid

is found in fruits of Tam-

arindus, oxalic acid in

Oxalis and citric acid in

Citrus fruits.

Nitrogenous waste products: Alkaloids:

These are nitrogenous compounds, made up of carbon, hydrogen, oxygen and ni-

trogen. They are found in storage organs of plants such as seeds, bark and leaves. They

are insoluble in water but soluble in alcohol. They have sour taste and some are poison-

ous. However, a large number of alkaloids, such as quinine, reserpine, nicotine, caffeine,

thein, strychnine, morphine, atropine, are used as medicines.

L. S. of

oil

gland in

orange

peel

Schizogenous cavity. Resin-duct of pine

stem with resin.

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A stamen typically consists of a stalk

called the filament and an anther which

contains microsporangia. Most commonly

anthers are two-lobed and are attached to

the filament either at the base or in the

middle portion. The sterile tissue between

the lobes is called the connective. The sta-

mens in a flower are collectively called

the androecium. The androecium in various

species of plants form a great variety of

patterns, some of them highly complex.

Organization /structure of anthers in flowers

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Descriptive terms: Androphore: A column formed from the fusion of multiple filaments is known as androphore. The anther can be attached to the filament's connective in two ways: Basifixed: attached at its base to the filament

Pseudobasifixed: a somewhat misnomer configure

tion where connective tissue extends in a tube

around the filament. Dorsifixed: attached at its center to the filament, usually versatile (able to move)

Stamens can be connate (fused or joined in the same whorl):

Extrorse: anther dehiscence directed away from the centre of the flower.

Cf. introrse, directed inwards, and latrorse towards the side.

Monadelphous: fused into a single, compound structure Declinate: curving downwards, then up at the tip (also - declinate-descending) Diadelphous: Joined partially into two androecial structures Pentadelphous: Joined partially into five androecial structures Synandrous: only the anthers are connate (such as in the Asteraceae).

The fused stamens are referred to as a synandrium.

Stamens can also be adnate (fused or joined from more than one whorl):

Epipetalous: adnate to the corolla Epiphyllous: adnate to undifferentiated tepals (as in many Liliaceae)

They can have different lengths from each other:

Didymous: two equal pairs

Didynamous: occurring in two pairs, a long pair and a shorter pair

Tetradynamous: occurring as a set of six stamens with four long

and two shorter ones

or respective to the rest of the flower (perianth):

Exserted: extending beyond the corolla

Included: not extending beyond the corolla

They may be arranged in one of two different patterns:

Spiral; or

Whorled: one or more discrete whorls (series)

They may be arranged, with respect to the petals:

diplostemonous: in two whorls, the outer alternating with the petals,

while the inner is opposite the petals.

obdiplostemonous: in two whorls, the outer opposite the petals

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Techniques of pollen preparation:

The morphological studies of

pollen include both Light microscopy

(LM) and Scanning Electron Microsco-

py (SEM). The pollengrains are pre-

pared by the acetolysis method original-

ly proposed by Erdtman (1952), and

subsequently revised by Nair (1960c).

The salient steps are as follows:

Mature flower buds are selected and

fixed in 70% ethyl alcohol.

Transfer the anthers with alcohol into a

polyethylene centrifuge tube.

Crush the anthers with a glass rod,

sieve through a brass metal sieve into a

glass centrifuge tube and centrifuge.

Decant the supernatant, add glacial

acetic acid to the sediment and centri-

fuge.

Decant the acid and add 5 ml freshly

prepared acetolysis mixture (9:1 acetic

anhydride and glacial sulphuric acid).

Keep the centrifuge tube in a water

bath at 70⁰C and bring to boiling.

The mixture is allowed to remain in the

hot water till the mixture attains dark

brown colour.

Centrifuge and decant off the superna-

tant.

Add glacial acetic acid to the sediment,

centrifuge and decant the acid.

Wash this with distilled water 3-4

times, centrifuge, decant water and add

a few drops of dilute glycerine and

keep aside for slide preparation.

Mount the acetolysed pollengrains on

microslides, observe under microscope

and describe the morphology of pol-

lengrains.

POLLEN MORPHOLOGY - PALYNOLOGY

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OVARIES, OVULES AND THEIR MODIFICATIONS

Aim: To study the morphology of ovaries, ovules with their modifications.

Theoretical background: In flowering plants, an ovary is a part of the female reproduc-

tive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds

the ovule(s) and is located above or below or at the point of connection with the base of

the petals and sepals. The pistil may be made up of one carpel or of several fused carpels

(e.g. tricarpel), and therefore the ovary can contain part of one carpel or parts of several

fused carpels. Above the ovary is the style and the stigma. Some wind pollinated flowers

have much reduced and modified ovaries.

Angiosperm ovules are diverse in their position in the ovary, nucellus thickness, number

and thickness of integuments, degree and direction of curvature, and histological differ-

entiations.

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Modifications in ovaries / ovules:

Aril: It is a specialized fleshy outgrowth from the funiculus (the attachment point of a

seed), which covers or is attached to the seed in some plants. It is

an accessory seed coating that may form a fleshy, cuplike structure around the immature

seed (ovules) as in pithecellobium yew and nutmeg. The aril is often brightly colored and

edible.

Caruncle: It is a small outgrowth from the testa of a seed that develops from the placen-

ta, funicle, or micropyle. Examples include the warty outgrowth from the castor-oil seed.

Hypostase: the hypostase consists of a well-defined but irregularly outlined group of

thick-walled cells at the chalazal end of the anatropous ovule, Eg. Onagraceae.

Aril: Nutmeg Fruit Nutmeg Seed with aril Aril in seeds of Taxus sp.

Pithecellobium– Fruits Pithecellobium Seed with aril Litchi fruit with aril

Caruncle in seed of Castor Pear fruit Fleshy thalamus in Cashew

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Determination of pollen viability

Aim: To determine the percentage of pollen viability.

Theory: All the Pollen grains – Microspores produced in the microsporangium are not

viable due to several factors. For various purposes like tissue culture, plant breeding, re-

productive biology etc, it is necessary to know the percentage of viable pollen grains.

There are several methods and the simple method is by acetocarmine staining method.

When the pollen grains are stained with acetocarmine stain, the viable pollen grains are

well stained and the non-viable pollen grains are not stained well. Based on this principle

the percentage of viable pollen grains is calculated.

Procedure: Collect pollen grains from mature undehisced anthers of different species

like Rose, Papaya, Banana, Hibiscus, etc. on different micro-slides. Put one or two drops

of acetocarmine stain. Put a covergalss and leave it for at least five minutes. The stained

and unstained pollen grains per microscopic field are counted and tabulated, The percent-

age of stained pollen grains is calculated as follows. Draw a histogram

.

Number of fertile (Stained) pollen grains

Pollen fertility (%) = ------------------------------------------------------- X 100

Total number of pollen grains

Result and conclusion: Pollen fertility is higher ( ..%) in ……….species than that in ….

species. The fertile pollen grains are also different in size (larger) and shape (irregular).

S.No. Percentage of viable (stained) pollen grains

Species 1

.. .... .. .. ..

Species 2

.. .... ....

Species 3

... ... ....

Species 4

... ..... .....

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Total

Average

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Effect of sucrose and pH on pollen germination

Aim: To study the effect of concentration of sucrose and pH on pollen germination.

Theory: After pollination, the pollen-grains germinate on the stigma where suitable nu-

trients and pH are available due to the secretion of several kinds of chemicals by the stig-

ma. We can study the important factors such as the nutrient sucrose (chemical factor) and

pH (physical factor) on pollen germination in artificial culture.

Procedure:

Pollen germination medium:

Sucrose - 10%

Boric Acid - 100mg / l

Calcium Nitrate - 300mg / l

Boric Acid and Calcium Nitrate are added at required amount and mixed in 10% sucrose

solution. Take three sets each of 50 ml or 100 ml of this basal medium and set the pH at

5.8, 6.2, 7, 7.8. In another set, prepare the medium with at least three different concentra-

tions of sucrose.

Take few drops of medium from each set in a cavity slide. Mix the pollen grains

of Balsam in the medium. Put the cover glass on the cavity slide. Leave it for germina-

tion. Observe the percentage of pollen germination and also the rate of pollen germina-

tion by measuring the length of pollen tube. Compare the results with different pH and

different concentrations of sucrose.

Table: Effect of pH and sucrose on pollen germination

S. No. Duration pH

5.8

pH

7

pH

7.8

Sucrose

….%

Sucrose

….%

Sucrose

…%

1. 20 minutes

2. 40 minutes

3. 60 minutes

4. 80 minutes

5. 120 minutes

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Effect of IAA and sugar on the apical bud:

Aim: To study the effect of IAA and sucrose on growth and anatomy (Vascular tissue

differentiation) in shoot apex.

Theory: Growth substances like IAA and sucrose applied to the apical bud move down-

wards and cause differentiation of vascular elements below. The young leaf primordium

of Ricinus communis also produces the growth hormone like IAA which helps the basipe-

tal differentiation of vascular elements. The exogenous application of IAA and sucrose

may stimulate rapid differentiation of vascular elements.

Procedure: Ricinus communis seeds are sown in the pots. After 20 days, the plants may

grow to 15 cm height. 1 ppm IAA and 1 % sucrose are applied on the apical bud region.

Morphological (shoot length) and anatomical (T.S & L.S) observations are made at regu-

lar intervals. Note the degree of differentiation of xylem and phloem.

Table . Effect of IAA and sucrose on apical bud

Results and Inference / Conclusion:

No. of days Control Apical bud treated with

IAA

Apical bud treated

with sucrose

5

10

15

20

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Effect of disruption of vascular continuity and regeneration of

vascular tissues

(Wound healing response in dicots and monocots)

Aim: To study the wound healing response in dicot and monocot plants.

Theory: Wound healing is a process of dedifferentiation. New tissue is formed due to

wound healing hormones.

Procedure: Make ‗V‘ shaped wound on the stem surface of matured plants of dicot and

monocot plants. Observe the morphological and anatomical (T.S & L.S) changes at regu-

lar intervals. Document the changes by diagrams or photomicrographs.

Observation:

Plant type / species Initial results Final results

after .......days

Dicot-Shrub

..............................

Dicot-Tree

..............................

Monocot plant

..............................

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