P LANT S TRUCTURE & G ROWTH Nancy G. Morris Volunteer State Community College Campbell, 5 th edition, Chapter 35

Plant Tissues I. Meristematic Tissue II. Dermal, Surface, or Protective III. Ground or Fundamental

I. 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 Protective 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 Fundamental

A. Paraenchyma – Figure unspecialized living primary cell wall thin & flexible capable of dividing metabolic synthesis storage of starch in plastids Chlorenchyma – specialized parenchyma photosynthetic

Paramechyma

III. Ground or Fundamental 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

Collenchyma

III. Ground or Fundamental C. SclerenchymaC. Sclerenchyma – Figure 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)

Sclerids or Stone Cells

III. Ground or Fundamental Vascular TissuesD. Vascular Tissues Xylem: 1. Xylem: 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

Xylem 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 in a sieve tube

Roles of cohesion & adhesion in the ascent of xylem sap

III. Ground or Fundamental D. Vascular TissuesD. Vascular Tissues – Figure Phloem 1. Phloem – 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

Phloem 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 phloem

Vessel Elements

Anatomy of an Angiosperm

The Angiosperm Body The 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 (Figure )

Root tip

Roots hairs

Lateral Root

Dicot Root

Monocot and Dicot Root Comparison

Casparian Strip

Shoot System: Shoot System: vegetative & floral shoots Stem morphology:Stem morphology: nodes –1) nodes – where leaves are attached to stems internodes –2) internodes – space between leaves axillary buds –3) axillary buds – bud in leaf axil terminal buds –4) terminal buds – bud on shoot tip Stem modifications:Stem modifications: stolons –1) stolons (strawberry runners) rhizomes –2) rhizomes (horizontal underground stems, irises) bulbs –3) bulbs (vertical, underground shoots with leaf bases modified for food storage,onions) tubers –4) tubers (potatoes- swollen ends of rhizomes) –Figure 35.6

Iris rhizomes

Figure 35.4 Stem Morpholo gy

Stem Anatomy

Production of Secondary Vascular Tissue

Anatomy of stem: Secondary Growth

All wrapped 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: –1) support –2) protection –3) storage –4) attract pollinators Leaf modifications:Leaf modifications: (Figure 35.8) –1) tendrils – cling for support –2) spines – protection –3) succulents – storage of water –4) color – attraction of pollinators

Figure Anatomy of a Leaf

Cross section of a mesophytic leaf

Gas Exchange through the stoma: Transpiration

Simple vs. Compound

Comparison of Monocots & Dicots

Uptake of nutrients

Angiosperms produce FlowersFlowers FruitsFruits SeedsSeeds

Anatomy of a Flower

Anatomy of a Seed

Germination: Hypogean & Epigean

Double Fertilization

Fruit Development

Embryo packaged in a seed

Plasmodesmata