the strucure and the function of plant tissues 7

8/10/2019 The Strucure and the Function of Plant Tissues 7

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At the end of lesson students are able: To explain the structure and function of tissue in

root, stem and leafcarefullyand honestly To show the position of epidermis, cortex and

stele in plantthinking logically To explain the function of specific tissue in plant

bodyproperly To explain the differences place between xylem

and phloemcaring about social matters andenvironment To differences structure both monocotyle and

dicotylecarefully and properly


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1. ROOT

2. STEM

3. LEAVES

4. FLOWERS5. FRUITS

6. SEEDS


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The roots help provide support by anchoringthe plant and absorbingwater and

nutrients needed for growth. They can also store sugarsand carbohydratesthe plant

uses to carry out other functions. Plants can have either a TAPROOT SYSTEM

(dicots) or a FIBROUS ROOT SYSTEM(monocots). In both cases, the roots are the

links between the water and nutrients needed for plant growth.

Primary function of root :1. Anchors plant in ground.

2. Absorbs water & minerals.

3. Storage of food made by leaves.


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WHOLE ROOT STRUCTURE :

1. Epidermis :

Outer layer of cells ("skin"), for protection.

2. Root Hair :

An extension of specialized root epidermal cells increasing

surface area for absorption of water & minerals.

3. Cortex :Region between epidermis & vascular cylinder. Supports plant

parts & stores food.

4. Endodermis :

Layer of cells just outside vascular cylinder.5. Pericycle :

Cylindrical layer of cells inside endodermis. Origin of cork &

secondary (side) roots.


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WHOLE ROOT STRUCTURE :

6. Vascular Cylinder :

Arrangement of vascular tissues as a central cylinder in roots.

This is shown as the large circular area in the middle of both

diagrams.

7. Xylem :

Living (inner) vascular system

carrying water & minerals

throughout plant.

8. Phloem :

Living (outer) vascular system

carrying dissolved sugars and

organic compounds throughout

plant.


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OTHERS :

Root Hairs :

Outward extensions ofepicermal cells which extend

between soil particles to collect

water and solutes (minerals).

Apical Meristem :

Cells near the tip that can

divide by mitosis to make any

type of plant cell.

Root Cap :

Dome-shaped mass of cells at the tip which protect the meristem

cells from damage (as root extends through soil).


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Primary tissues of a root :

1. Epidermis

2. Cortex

3. Endodermis4. Central core (stele) :

Pericycle and

vascular bundles


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Stems conducts water and minerals in the vascular bundles,usually from the root upwards to the leaves via the

XYLEM; and, food materials move from the leaves to other

parts of the plant by way of the PHLOEM.

In some plants, stems may become specialized to storelarge

amounts of food and/or water.

Stems that grow above the ground are called aerial stems;

however, some plants have underground stems(rhizome).

There are 2 types of aerial stems: herbaceousand woody.

Herbaceous stems have almost all primary tissue (derived

from the apical meristem), and are usually green, and soft.

They lack hard woody tissue.


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Most plants that live for only one year(annuals) have

herbaceousstems. Plants that live for more than two

years, perennials, have woodystems; for example,

trees.

Woody stems are composed mostly of secondary

tissues. Secondary tissues are derived from secondary

meristems: vascularcambium and corkcambium.


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The major function of leaves is the production of food by

photosynthesis. LEAVESmay also be modified for foodstorage(onion) and protection of the plant(cactus).


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Leaves are the food making factories of green plants.

Leaves come in many different shapes and sizes.

Leaves can be simple(one leaf attached to a stem), madeof a single leaf blade connected by a petioleto the stem

(oak, maple), or compound(a leaf that is made up of a

bunch of smaller leaves called leaflets), in which the leaf

blade is divided into separate leaflets attached by a petioleto the stem.

Petioleis the part that joins the leaves of a plant to the main stem.


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Leaves are made to catch lightand have openings to allow

water and air to come and go. The outer surface of the leaf

has a waxy coatingcalled a cuticlewhich protects the leaf.Veinscarry water and nutrients within the leaf.


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Leaves are the site of food making process called

photosynthesis. In this process, carbon dioxide andwater in the presence of chlorophyll(the green

pigment) and lightenergyare changed into glucose(a

sugar). This energy rich sugar is the source of food

used by most plants.

Photosynthesis is special to green plants.

Photosynthesissupplies food for the plant and

oxygen for other forms of life.


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Flowers not only look pretty, but in fact are important in

making seeds. Flowers have some basic parts. The female

part is the pistil(putik). The pistil usually is located in the

center of the flower and is made up of of 3 parts: thestigma(stigma), style(stilus), and ovary(ovarium).

The stigma is the sticky knob at the top of the pistil. It is

attached to the long, tubelike structure called the style.

The style leads to the ovary which contains the female eggcells called ovules(bakal biji).

See page 66 (See also : http://www.urbanext.uiuc.edu/gpe/case1/c1facts2d.html)


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The male parts are called

stamenand usually surround

the pistil. The stamen ismade up of two parts: the

antherand filament.

The anther produces pollen

(male reproductive cells).The filament holdsthe anther

up.

During the process of fertilization, pollen lands on the

stigma, a tube grows down the style and enters the ovary.Male reproductive cells travel down the tube and join with

the ovule, fertilizing it. The fertilized ovule becomes the seed,

and the ovary becomes the fruit.


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The fruit is the ripened ovaryof a plant containing the seeds.

After fertilization, the ovary swells and becomes either fleshy

or hard and dry to protect the developing seeds. Many fruits

help seeds spread (maple seeds). Many things we callvegetablesare really fruits (tomato, cucumber, beans).

Every seedis a tiny plant (embryo) with leaves, stems, and

root parts waiting for the right things to happen to make it

germinate and grow. Seeds are protected by a coat. This coat

can be thin or thick and hard. Thin coats don't protect the

embryo well. But thick coats can let the embryo survive some

tough conditions.


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The seed also contains a short-term food

supply called endosperm. This is found

in the plant's cotyledons. Plants with one

cotyledon(like corn) are called monocots(a plant that has only one cotyledon.

Corn is an example).

If they have two cotyledons (like beans),

they are called dicots(a plant that has 2cotyledon. Bean is an example).

Seeds are a plant's wayof getting from

one area to another.

Cotyledon look like leaves and they are the first plant part you

see when a seedling pokes its head out of the ground.

Cotyledonshelp keep the new seedling fed until it can make its

own food.

the strucure and the function of plant tissues 7

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