RITGenBio2 Chapter 23

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Kingdom Plantae: 4 Types

 * 1) Bryophytes (mosses)
 * 2) Seedless vascular plants (ferns)
 * 3) Gymnosperms (evergreen trees) [naked seeds]
 * 4) Angiosperms (everything else) [vessel seeds]
 * 5) * more species (250,000) than all other plant types combined
 * 6) * big advantages - the flower, animal pollination, fruit

By life cycle

 * annual
 * biennial
 * perennial

By Evolutionary lineage

 * monocot
 * many crop plants, grasses, palm trees, orchids, wheat, rice, bananas
 * embryonic leaves - one cotyledon
 * mature leaves - narrow leaves, parallel veins
 * roots - fibrous root system (random)
 * vascular bundles - scattered throughout stem
 * type of growth - only primary growth (thickness / width / girth)
 * flower parts - multiples of three
 * dicot
 * carnations, grapes, peas, roses, oak, maple. 75% of all angiosperms
 * embryonic leaves - two contyledons
 * mature leaves - broad leaves, branching veins
 * roots - taproot system (one main root straight down, branches off that)
 * vascular bundles - arranged in ring in stem
 * type of growth - may have secondary woody growth
 * flower parts - multiples of 4 or 5

Plant Structure

 * 1) Cells
 * 2) * parenchyma
 * 3) ** most abundant in plant
 * 4) ** connective tissue
 * 5) ** thin walled
 * 6) ** living
 * 7) ** metabolically active
 * 8) ** functions - photosynthesis, storage (roots), repair
 * 9) ** can differentiate into other cell types, even regenerate whole organ or entire plant
 * 10) * sclerenchyma
 * 11) ** generally dead at maturity
 * 12) ** cellulose & lignin
 * 13) ** thick lignified walls
 * 14) ** functions - provide mechanical strength and rigidity
 * 15) * collenchyma
 * 16) ** living
 * 17) ** perform some parenchyma functions, but also provide strengthening in young, growing tissues
 * 18) ** walls irregularly thickened
 * 19) ** very plastic properties and functions (changing)
 * 20) Tissues
 * 21) * dermal
 * 22) ** outer covering
 * 23) ** usually one cell thick
 * 24) ** bears stomata and trichomes on shoots
 * 25) ** keep water in, bad stuff out though thick cuticle
 * 26) ** guard cells of stomata let things in and out (gas)
 * 27) ** root hairs
 * 28) * vascular
 * 29) ** xylem (carries water) and phloem (carries sugar)
 * 30) ** provides strength
 * 31) ** bundles in stem
 * 32) *** phloem on outside
 * 33) *** xylem toward center
 * 34) * meristematic
 * 35) ** "stem cell" areas
 * 36) ** capable of growth
 * 37) ** localized at tips of shoots (top of plant) and roots
 * 38) ** able to give rise to all cell types
 * 39) ** Types
 * 40) *** Apical Meristem:
 * 41) **** Primary growth (extend shoot and root)
 * 42) *** Vascular Cambium:
 * 43) **** Secondary growth in woody dicots
 * 44) *** Cork cambium
 * 45) **** growth of bark in woody dicots
 * 46) * ground
 * 47) ** everything else
 * 48) ** forms bulk of all tissue
 * 49) ** All three cell types (parenchyma, collenchyma, sclerenchyma)
 * 50) ** thus all their functions are possible
 * 51) Organs
 * 52) * leaves, stem, roots, flower
 * 53) Organ systems
 * 54) * transport
 * 55) * hormonal
 * 56) * reproduction

Primary growth

 * vertical growth
 * shoot grows up, roots grow down
 * Apical meristems set up during embryonic life
 * lateral buds become branches or flowers
 * Intercalary meristem
 * meristematic tissue causes internode growth (throughout the plant, not just the top)
 * example: cutting the grass, it still grows back
 * Root apical meristem is protected by the root cap
 * Much of growth is really due to elongation (cell elongation)

Secondary growth

 * lateral / "woody" growth (thickening of stem)
 * only occurs in some dicots (trees)
 * occurs via division of vascular cambium and cork cambium meristematic tissue
 * Types:
 * Vascular cambium - gives rise to secondary phloem and secondary xylem
 * The tough secondary xylem produced is "wood"
 * cork cambium - gives rise to outer tissues
 * bark
 * filled with waxy invader-proof, waterproof substance
 * New secondary xylem (wood) is on the inside of the tree (near the center)
 * New secondary phloem is on the outside


 * Plant tissue develops in 3 zones or stages
 * Cell Division
 * Elongation
 * Differentiation

< Insert Primary and Secondary Growth Summary diagram from text book >