plant tissues and the multicellular plant body chapter 5

Plant Tissues and the Plant Tissues and the Multicellular Plant BodyMulticellular Plant Body

Chapter 5Chapter 5

LEARNING OBJECTIVE 1LEARNING OBJECTIVE 1

• Discuss the Discuss the plant bodyplant body, including the , including the root systemroot system and and shoot systemshoot system

The Plant Body 1The Plant Body 1

• Root systemRoot system • generally underground generally underground • obtains water and dissolved minerals for plant obtains water and dissolved minerals for plant • usually anchors the plant firmly in place usually anchors the plant firmly in place


• Shoot systemShoot system • generally aerial generally aerial • obtains sunlight and carbon dioxide for plant obtains sunlight and carbon dioxide for plant

• Shoot system consists of Shoot system consists of • a vertical stem bearing leaves (main organs of a vertical stem bearing leaves (main organs of

photosynthesis) photosynthesis) • flowers and fruits (reproductive structures) flowers and fruits (reproductive structures)


• BudsBuds (undeveloped embryonic shoots) (undeveloped embryonic shoots) develop on stems develop on stems

• Although separate Although separate organsorgans (roots, stems, (roots, stems, and leaves) exist in the plant, many and leaves) exist in the plant, many tissuestissues are integrated throughout the are integrated throughout the plant body, providing continuity from organ plant body, providing continuity from organ to organto organ

The Plant BodyThe Plant Body

Branch roots

Developing fruit

Nodes (areas of leaf andaxillary bud attachment)

Axillary bud

Flower

Internode (area betweenadjacent nodes)

Shootsystem

Rootsystem

Rosette ofbasal leaves

Petiole Blade

LeafStem

Taproot

Fig. 5-1, p. 92

Developing fruit

Flower

Nodes (areas of leaf and axillary bud attachment)

Axillary bud

Internode (area between adjacent nodes)

Petiole Blade

Leaf

Taproot

Branch roots

Root system

Stem

Rosette of basal leaves

Shoot system

Stepped Art

Fig. 5-1, p. 92

KEY TERMSKEY TERMS

• GROUND TISSUE SYSTEMGROUND TISSUE SYSTEM • All tissues of the plant body other than All tissues of the plant body other than

vascular tissues and dermal tissuesvascular tissues and dermal tissues

• VASCULAR TISSUE SYSTEMVASCULAR TISSUE SYSTEM • Tissue system that conducts materials Tissue system that conducts materials

throughout the plant bodythroughout the plant body

• DERMAL TISSUE SYSTEMDERMAL TISSUE SYSTEM • Tissue system that provides an outer covering Tissue system that provides an outer covering

for the plant bodyfor the plant body

3 Tissue Systems in Plant Body3 Tissue Systems in Plant Body

Dermal tissue system



Vascular tissue system



Ground tissue system



(a) Leaf

(b) Stem

(c) Root

Fig. 5-2, p. 94


• Describe the Describe the ground tissue systemground tissue system ((parenchyma tissue, collenchyma parenchyma tissue, collenchyma tissue,tissue, and and sclerenchyma tissuesclerenchyma tissue) of ) of plantsplants

KEY TERMSKEY TERMS

• PARENCHYMA CELLPARENCHYMA CELL • Relatively unspecialized plant cell; thin walled, Relatively unspecialized plant cell; thin walled,

may contain chlorophyll, loosely packedmay contain chlorophyll, loosely packed

• COLLENCHYMA CELLCOLLENCHYMA CELL • Living plant cell with moderately but unevenly Living plant cell with moderately but unevenly

thickened primary wallsthickened primary walls

• SCLERENCHYMA CELLSCLERENCHYMA CELL • Plant cell with extremely thick walls; provides Plant cell with extremely thick walls; provides

strength and support to plant bodystrength and support to plant body

Ground Tissue System 1Ground Tissue System 1

• Parenchyma tissueParenchyma tissue • Composed of living Composed of living parenchyma cellsparenchyma cells with with

thin thin primary cell wallsprimary cell walls • Functions include photosynthesis, storage, Functions include photosynthesis, storage,

and secretion and secretion

Parenchyma CellsParenchyma Cells

(a) Parenchyma cells from an epidermal peel of red onion (Allium cepa). The large vacuole contains pigmented material and occupies most of the cell. The nucleus and cytoplasmic strands are positioned under and on top of the vacuole, between it and the plasma membrane.

Onion

NucleusVacuole

Fig. 5-3a, p. 96

(b) Some parenchyma cells contain chloroplasts, and their primary function is photosynthesis. These parenchyma cells are from a waterweed (Elodea) leaf.

Elodea

Chloroplasts

Fig. 5-3b, p. 96

(c) Parenchyma cells often function in storage. These parenchyma cells are from a buttercup (Ranunculus) root. Note the starch grains filling the cells.

Buttercup

Starchgrains

Fig. 5-3c, p. 96


• Collenchyma tissueCollenchyma tissue • Composed of Composed of collenchyma cellscollenchyma cells with with

unevenly thickened primary cell walls unevenly thickened primary cell walls • Provides flexible structural support Provides flexible structural support

Collenchyma CellsCollenchyma Cells

Thick cell walls at cornersof 4 cells

Water lily

Cell's interior

Fig. 5-4, p. 97


• Sclerenchyma tissueSclerenchyma tissue • Composed of Composed of sclerenchyma cellssclerenchyma cells with both with both

primary and secondary cell walls primary and secondary cell walls • Sclerenchyma cells are often dead at Sclerenchyma cells are often dead at

maturity, but provide structural supportmaturity, but provide structural support

Sclerenchyma CellsSclerenchyma Cells

Cherry Bamboo

Fiber cells

Parenchymacell

(a) Sclereids from a cherry (Prunus avium) stone. The cell walls are extremely thick and hard, providing structural support.

(b) Long, tapering fibers and shorter parenchymacells from a bamboo (Bambusa) stem. The stemwas treated with acid to separate the cells.

Fig. 5-5, p. 97


• Outline the structure and function of Outline the structure and function of the the vascular tissue systemvascular tissue system ( (xylemxylem and and phloemphloem) of plants ) of plants

Vascular Tissue SystemVascular Tissue System

• Conducts materials throughout the plant Conducts materials throughout the plant body and provides strength and support body and provides strength and support • XylemXylem • PhloemPhloem

KEY TERMSKEY TERMS

• XYLEM XYLEM • A complex vascular tissue that conducts water A complex vascular tissue that conducts water

and dissolved minerals throughout the plant and dissolved minerals throughout the plant bodybody

• Actual conducting cells of xylem are Actual conducting cells of xylem are tracheidstracheids and and vessel elementsvessel elements

XylemXylem

Tracheids

Pits

White pine tree

(a) Tracheids from a white pine (Pinus strobus) stem in longitudinal section (that is, cut lengthwise). These cells, which occur in clumps, transport water and dissolved minerals. Water passes readily from tracheid to tracheid through pits, thin places in the cell wall.

Fig. 5-6a, p. 98

Vessel elements

Pumpkin plant

(b) Vessel elements from a pumpkin (Cucurbita mixta) stem in longitudinal section. The blue-stained regions are various patterns of the secondary walls in the vessel elements. Perforation plates are not visible in this micrograph. Fig. 5-6b, p. 98

Adjacentperforationplates

Southern magnolia

(c) The end walls of vessel elements, called perforation plates, have large holes. Waterpasses through the perforation plate from one vessel element to the next. Shown are adjacent perforation plates from a southern magnolia (Magnolia grandiflora) stem; in this species, the perforation plates are at an angle in longitudinal section. Fig. 5-6c, p. 98

Pit PairsPit Pairs

Pits

Middle lamella Primarycell walls

Simplepit

Tracheid

Permeableprimary cellwall pair

Cell B

Impermeablesecondarycell walls

Cell A

(a) A simple pit pair has an interruption in the secondary cell wall. The primary cell wall in a simple pit pair is permeable to water. Fig. 5-7a, p. 101

Primarycell walls

Secondarycell walls

Pit borders

Cell A Cell B

Torus

Borderedpit

(a) A simple pit pair has an interruption in the secondary cellwall. The primary cell wall in a simple pit pair is permeable towater.

Fig. 5-7b, p. 101

Water

Water

Cell A Cell BCell A Cell B

Pressurecloses pit

H2O

(c) (Left ) When water pressure is equal between the twocells (A and B), the bordered pit is open, and water flow isunrestricted. (Right ) When the pressure is greater in cell Athan in cell B, the torus, a thickening in the primary cellwalls, blocks the opening, restricting water movementthrough the pit pair.

Fig. 5-7c, p. 101

KEY TERMSKEY TERMS

• PHLOEM PHLOEM • A complex vascular tissue that conducts food A complex vascular tissue that conducts food

(carbohydrate) throughout the plant body(carbohydrate) throughout the plant body

• Conducting cells of phloem are Conducting cells of phloem are sieve-tube sieve-tube elementselements assisted by assisted by companion cellscompanion cells

PhloemPhloem

CompanioncellSquash leaves

Crosssection

Sieve-tubeelements

Sieveplate

(a) Phloem tissue from a squash (Cucurbita) petiole in cross section. Note thesieve plates, the end walls of the sieve-tube elements. Most sieve-tube elementsappear empty because they were sectioned in the middle of the cells rather thanat the end walls. The smaller cells are companion cells.

Fig. 5-8a, p. 102

Sieve-tubeelement

Longitudinalsection

Squash leaves

Sieve plate

(b) Phloem tissue from a squash (Cucurbita) petiole in longitudinal section.

Companion cell

Fig. 5-8b, p. 102


• Describe the Describe the dermal tissue systemdermal tissue system ((epidermisepidermis and and peridermperiderm) of plants) of plants

Dermal Tissue SystemDermal Tissue System

• Outer protective covering of the plant body Outer protective covering of the plant body • EpidermisEpidermis • PeridermPeriderm

KEY TERMSKEY TERMS

• EPIDERMISEPIDERMIS • Outermost tissue layer, usually one cell thickOutermost tissue layer, usually one cell thick• Covers the primary plant body (leaves, young Covers the primary plant body (leaves, young

stems and roots)stems and roots)

EpidermisEpidermis

• EpidermisEpidermis covering aerial parts secretes a covering aerial parts secretes a wax layer wax layer (cuticle)(cuticle) that reduces water loss that reduces water loss

• Gas is exchanged between interior of shoot Gas is exchanged between interior of shoot system and surrounding atmosphere system and surrounding atmosphere through through stomatastomata

EpidermisEpidermis

Epidermal cells

Spiderwort

Stoma

Guard cells

Fig. 5-9, p. 103

KEY TERMSKEY TERMS

• PERIDERMPERIDERM • Outermost layer of cells covering a woody Outermost layer of cells covering a woody

stem or root (the outer bark that replaces stem or root (the outer bark that replaces epidermis when it is destroyed during epidermis when it is destroyed during secondary growth)secondary growth)

PeridermPeriderm

Geranium

Cortex(interior of stem)

Exteriorenvironment

Remnantsof epidermis

Cork cellsCork cambium

Per

ider

m

Corkparenchyma

Fig. 5-10, p. 103


• Discuss what is meant by growth in Discuss what is meant by growth in plants and how it differs from growth in plants and how it differs from growth in animals animals

Growth in PlantsGrowth in Plants

• Involves cell division, cell elongation, and Involves cell division, cell elongation, and cell differentiationcell differentiation

• Plants grow only in specific areas Plants grow only in specific areas ((meristemsmeristems) ) composed of cells that do not composed of cells that do not differentiatedifferentiate

Growth in AnimalsGrowth in Animals

• Location of growth differs between plants Location of growth differs between plants and animalsand animals

• When a young animal grows, all parts of When a young animal grows, all parts of its body grow, although not necessarily at its body grow, although not necessarily at the same rate the same rate


• Distinguish between Distinguish between primaryprimary and and secondary growthsecondary growth

KEY TERMSKEY TERMS

• PRIMARY GROWTHPRIMARY GROWTH • An increase in stem and root length due to the An increase in stem and root length due to the

activity of activity of apical meristemsapical meristems at the tips of at the tips of roots and at the roots and at the budsbuds of stems of stems

KEY TERMSKEY TERMS

• APICAL MERISTEMAPICAL MERISTEM • An area of cell division at the tip of a stem or An area of cell division at the tip of a stem or

root in a plant; produces primary tissuesroot in a plant; produces primary tissues

• BUD BUD • A dormant embryonic shoot that eventually A dormant embryonic shoot that eventually

develops into an apical meristemdevelops into an apical meristem

Root TipRoot Tip

Apicalmeristem

Procambium

Ground meristem

Protoderm

Root hairs

Root cap

Area of cell division

Area of cellelongation

Area of cellmaturation

Fig. 5-11, p. 105

Stem TipStem Tip

Coleus

Budprimordium

Trichome

Olderleaf

Apicalmeristem

Leafprimordia

Olderleaf

Fig. 5-12, p. 106

Stem Tip DevelopmentStem Tip Development

Stem apicalmeristem

Primary phloemPrimary xylemPithProcambiumCortex

Area of celldivision

Area of cellelongation

Epidermis

Area of cellmaturation

Ground meristemProcambiumProtoderm

Procambium

Immature leaf

Fig. 5-13, p. 106

KEY TERMSKEY TERMS

• SECONDARY GROWTHSECONDARY GROWTH • An increase in a plant’s stem and root girth An increase in a plant’s stem and root girth

due to the activity of due to the activity of lateral meristemslateral meristems (the (the vascular cambiumvascular cambium and and cork cambiumcork cambium))

Secondary GrowthSecondary Growth

• Woody plants have secondary growth Woody plants have secondary growth • In addition to primary growthIn addition to primary growth

• Secondary growth is localized, typically as Secondary growth is localized, typically as long cylinders of active growth throughout long cylinders of active growth throughout the lengths of older stems and roots the lengths of older stems and roots

KEY TERMSKEY TERMS

• LATERAL MERISTEMLATERAL MERISTEM • An area of cell division on the side of a An area of cell division on the side of a

vascular plant; the two lateral meristems vascular plant; the two lateral meristems ((vascular cambiumvascular cambium and and cork cambiumcork cambium) give ) give rise to secondary tissuesrise to secondary tissues

Lateral Meristems and Lateral Meristems and Secondary GrowthSecondary Growth

Bark

Outer bark (periderm)

Inner bark (secondary phloem)

Surface of vascular cambium

Wood(secondary xylem)

Fig. 5-14, p. 107

Animation: Tissue Systems of Animation: Tissue Systems of a Tomato Planta Tomato Plant

CLICKTO PLAY

root_structure.swfroot_structure.swf

Animation: Root OrganizationAnimation: Root Organization

CLICKTO PLAY

Animation: Shoot Animation: Shoot DifferentiationDifferentiation

CLICKTO PLAY

Transport in Plants: AnimationsTransport in Plants: Animations

• http://plantandsoil.unl.edu/croptechnologyhttp://plantandsoil.unl.edu/croptechnology2005/pages/animationOut.cgi?anim_name2005/pages/animationOut.cgi?anim_name=RootUptake.swf=RootUptake.swf

• http://wps.aw.com/http://wps.aw.com/bc_nabors_botany_1/15/4076/1043540.cwbc_nabors_botany_1/15/4076/1043540.cw/nav_and_content/index.html/nav_and_content/index.html

plant tissues and the multicellular plant body chapter 5

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