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
The Plant Body 2The Plant Body 2
• 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)
The Plant Body 3The Plant Body 3
• 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
Dermal tissue system
Dermal tissue system
Vascular tissue system
Vascular tissue system
Vascular tissue system
Ground tissue system
Ground tissue system
Ground tissue system
(a) Leaf
(b) Stem
(c) Root
Fig. 5-2, p. 94
LEARNING OBJECTIVE 2LEARNING OBJECTIVE 2
• 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
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
Ground Tissue System 2Ground Tissue System 2
• 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
Ground Tissue System 3Ground Tissue System 3
• 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
LEARNING OBJECTIVE 3LEARNING OBJECTIVE 3
• 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
Pit PairsPit Pairs
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
LEARNING OBJECTIVE 4LEARNING OBJECTIVE 4
• 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
LEARNING OBJECTIVE 5LEARNING OBJECTIVE 5
• 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
LEARNING OBJECTIVE 6LEARNING OBJECTIVE 6
• 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
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Animation: Root OrganizationAnimation: Root Organization
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Animation: Shoot Animation: Shoot DifferentiationDifferentiation
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Transport in Plants: AnimationsTransport in Plants: Animations
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