PPLANT LANT SSTRUCTURE & TRUCTURE & GGROWTHROWTH

Nancy G. MorrisVolunteer State Community College

Campbell, 5th edition, Chapter 35

Plant TissuesPlant Tissues

• I. Meristematic Tissue

• II. Dermal, Surface, or Protective

• III. Ground or Fundamental

I. Meristematic TissueI. Meristematic Tissue

• A. Apical MeristemsA. Apical Meristems• Primary growing tips of shoots & stems

• B. Lateral MeristemsB. Lateral Meristems• Produces lateral growth; increase in girth

• 1. Vascular Cambium• Between primary xylem & phloem

• 2. Cork Cambium• Between bark and phloem

II. Dermal, Surface, or II. Dermal, Surface, or ProtectiveProtective• A. Roots

– root hairs for adsorption– no waxy covering

• B. Stems – cork, cork cambium

• C. Leaves– trichomes (multicellular leaf hairs)– waxy cuticle on epidermis– stoma on lower dermis– Special xerophytic adaptations

• A. ParenchymaA. Parenchyma• 1. Storage Parenchyma• 2. Chloroenchyma

• B. CollenchymaB. Collenchyma• C. SclerenchymaC. Sclerenchyma• 1. Fibers• 2. Sclerids

• D. Vascular TissuesD. Vascular Tissues • 1. Xylem• a. tracheids• b. xylem vessels• 2. Phloem

III. Ground or III. Ground or FundamentalFundamental

III. Ground or III. Ground or FundamentalFundamental

• A. Paraenchyma – Figure 35.11• unspecialized• living • primary cell wall thin & flexible• capable of dividing• metabolic synthesis • storage of starch in plastids

• Chlorenchyma – specialized parenchyma

• photosynthetic

ParamechymaParamechyma

III. Ground or III. Ground or FundamentalFundamental

• B. Collenchyma – • primary cell walls thickened at corners • grouped in strands or cylinders to

support • living cells which elongate as plant

grows• Figure 35.11

CollenchymaCollenchyma

III. Ground or III. Ground or FundamentalFundamental

• C. C. SclerenchymaSclerenchyma – Figure 35.11

• dead cells• rigid, thick secondary cell walls of

lignin• support for non-growing parts of the

plant• fibers – • long, slender, tapered cells in bundles• sclereids – (pears: stone cells)

• shorter, irregularly shaped cells

Fiber cells (Bundle cap)Fiber cells (Bundle cap)

Sclerids or Stone CellsSclerids or Stone Cells

III. Ground or FundamentalIII. Ground or Fundamental• D. Vascular TissuesVascular Tissues • 1. XylemXylem:: water-conducting cells

secondary cell walls laid down in spiral/ ring patterns (which allow stretching) growing parts

• a. Tracheids – long, thin, tapered cells with lignin walls and bordered pits

» Water flows from cell to cell through pits» Also function in support

• b. Xylem vessel – wider, shorter, thinner- walled, less tapered (Figure 35.9)

» Aligned end to end to make an element» Hollow tubes

XylemXylem

• conducts water• tracheids evolved first• found in soft woods

(balsam, pine)• hard woods have both

tracheids & xylem vessels• thick walls • dead at maturity

Pressure flow Pressure flow in a sieve tubein a sieve tube

Roles of Roles of cohesion & cohesion & adhesion in adhesion in the ascent the ascent of xylem of xylem sapsap

III. Ground or FundamentalIII. Ground or Fundamental

• D. Vascular TissuesD. Vascular Tissues – Figure 35.9

• 1. . PhloemPhloem – food-conducting cells• living• thin-watery cytoplasm• sieve-tube members transport sucrose• sieve plate -perforated end wall • callose slime plugs prevent leakage• companion cells provide nuclear control•

PhloemPhloem

• alive at maturity• non-nucleated• nuclear control by Companion Cells• sieve-tube members are the sugar-

transporting cells• possess sieve plates between

adjacent cells• slime plugs of callose prevent

leaking when damaged

35.9 Food-conducting cells of the phloem35.9 Food-conducting cells of the phloem

Vessel ElementsVessel Elements

Anatomy of Anatomy of an an AngiospermAngiosperm

The Angiosperm BodyThe Angiosperm Body

Roots & shoots are adaptations to living on land!

• Roots functions:Roots functions: – 1) anchor the plant on land– 2) absorb & conduct water & minerals– 3) store food (tap root)

• Root types:Root types:– 1) tap root – carrots, turnips, sweet

potatoes– 2) fibrous root – primarily in monocots

• Root features:Root features:– 1) root hairs – increase surface area– 2) mycorrhizae – symbiotic root fungus– 3) adventitious roots – above ground –

prop roots

Root Structure Root Structure (Figure(Figure 35.14 ) 35.14 )

Root tipRoot tip

Roots hairsRoots hairs

Lateral RootLateral Root

Dicot RootDicot Root

Monocot and Dicot Root Monocot and Dicot Root ComparisonComparison

Casparian StripCasparian Strip

Shoot System:Shoot System: vegetative & floral shoots

• Stem morphology:Stem morphology: – 1) nodesnodes – where leaves are attached to stems– 2) internodesinternodes – space between leaves– 3) axillaryaxillary budsbuds – bud in leaf axil– 4) terminalterminal budsbuds – bud on shoot tip

• Stem modificationsStem modifications::– 1) stolonsstolons (strawberry runners)– 2) rhizomesrhizomes (horizontal underground stems,

irises)– 3) bulbsbulbs (vertical, underground shoots with

leaf bases modified for food storage,onions)– 4) tuberstubers (potatoes- swollen ends of rhizomes)– Figure 35.6

Iris rhizomesIris rhizomes

Figure 35.4Figure 35.4

StemStemMorpholoMorphologygy

Stem AnatomyStem Anatomy

Stem AnatomyStem Anatomy

Production of Secondary Vascular TissueProduction of Secondary Vascular Tissue

Anatomy of Anatomy of stem: stem: Secondary Secondary GrowthGrowth

All All wrapped wrapped up!up!

Shoot System:Shoot System: vegetative & floral shoots

• Leaf functions:Leaf functions: • Absorption of light energy for photosynthesisAbsorption of light energy for photosynthesis

– Other modifications:Other modifications:– 1) support1) support– 2) protection2) protection– 3) storage3) storage– 4) attract pollinators4) attract pollinators

• Leaf modificationsLeaf modifications:: (Figure 35.8)– 1) tendrils – cling for support1) tendrils – cling for support– 2) spines – protection2) spines – protection– 3) succulents – storage of water3) succulents – storage of water– 4) color – attraction of pollinators4) color – attraction of pollinators

Figure 35.20 Anatomy of a LeafFigure 35.20 Anatomy of a Leaf

Cross section of a mesophytic leafCross section of a mesophytic leaf

Gas Exchange through the stoma:Gas Exchange through the stoma:TranspirationTranspiration

Simple vs. CompoundSimple vs. Compound

Comparison of Monocots & Comparison of Monocots & DicotsDicots

Uptake Uptake of of nutrientsnutrients

Angiosperms Angiosperms produce produce

•Flowers Flowers

•Fruits Fruits

•Seeds Seeds

Anatomy of a FlowerAnatomy of a Flower

Anatomy Anatomy of a of a SeedSeed

Germination: Germination: Hypogean & Hypogean & EpigeanEpigean

PlasmodesmataPlasmodesmata