Bio- ch. 24
Terms
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- root system functions
- anchor, absorb, store sugar, transport to shoots, hormones
- shoot system fucntions
- photosynthesis, transport (b/t leaves, flowers, fruits, roots), reproduction, hormone synthesis
- two types of flowering plants
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monocots: seeds w/ 1 leaf (grasses, lilies, orchids)
dicots: seeds w/ 2 leaves (branching, tree, bushes) - two cell types
-
meristem: undifferentiated, cell division, keep plant growing
differentiated: stable parts, cells w/ job - meristem cells
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apical: located at end of roots and shoots
lateral: sides of roots and shoots - two forms of plant growth
- primary and secondary
- primary growth
-
= elongation
root cap: protects apical meristem, thick cell walls, lubricant - secondary growth
- division of lateral meristem, differentiation, growth in width/diameter
- 3 plant tissues
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dermal (covering of body)
ground (most of young plant)
vascular (xylem and phloem) - dermal tissue
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epiderm:outermost layer, covers (cuticle/root hairs)
periderm: replaces epidermal of woody plants as age (cork cells) -
cuticle/root hairs
cork cells -
cuticle:waxy substance to prevent water loss
root hairs:increase surface area --> more water absorbtion
cork cells:thick waterproof walls, bark = dead - ground tissue
-
all non dermal, non vascular
3 types: parenchyma, collenchyma, sclerenchyma - parenchyma
- most abundant, thin walled, alive, metobolic activity (photosynthesis/storage)
- collenchyma
- elongated cells w/ irregularly thick walls, alive, support
- sclerenchyma
- thick second wall, use lignin, dead, support
- vascular tissue
- xylem and phloem = transport everything
- xylem
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water and minerals from roots to shoots
2 cells: tracheids/vessel elements - tracheids
- thin walled cells, slanted, overlapping pits --> tube
- vessel elements
- larger, open tubes after death
- phloem
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carries water/dissolved substances made by plant
made of seive tubes - seive tubes
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strand of cells made by sieve tube elements
-ends connected by sieve plates (contain pores)
-companion cells: provide nourishment - leaves
-
major photosynthetic structure of plants
must balance need for surface area and need to keep water in - 2 parts of leaves
- blade and petiole
- blade
- broad, flat part, sun exposure, vascular bundles in veins
- petiole
- stem that attaches blade to shoot, carry vascular tissues
- terminal bud
- apical meristem surrounded by developing leaves
- daughter cells
- of apical meristem differentiate to form stem buds leaves and flowers
- lateral buds
- grow into branches
- internodes
- spaces b/t nodes
- 4 types of tissue in young stems
- epidermis, vascular, cortex, pith
- epdermis
- cuticle and stomata (stop water loss while allowing CO2 to enter)
- cortex
- b/t epidermis and vascular tissue
- pith
- located inside vascular tissues at center of stem
- functions of cortex/pith
-
support (fill w/ water --> turgor)
storage (store startch)
photosynthesis - secondary growth in stems
-
makes stronger
vascular cambrium/secondary xylem/phloem - vascular cambrium
-
produces secondary xylem/phloem
inner = xylme
outer = phloem - young/old xylem
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young: sapwood (transports)
old: heartwood (strength of tree) - secondary phloem
- weak, die when crused by xylem
- secondary growth -->
- epidermis replaced, lateral meristem (bark) instead
- primary root
-
first root to develop from seed
taproot and fibrous root - taproot roots
- dicot: carrot, grows larger and larger
- fibrous roots
- monocots: dies and replaced
- apical meristem in root
- produces: epidermis, vascular tissues, cortex
- cortex in root
- most of interior - beneath epidermis
- pericycle
- outermost layer of vascular tissue and remnant of meristem, can still divide