SBI3UO plants

Roots:
function:
-absorb water and nutrients
-anchor plant in soil
-store food

Primary Roots:
-first root from seed
Secondary Roots:
-any new root after primary root (from pericycle)

Herbaceous Stems:
-soft, green, survive one year, contain xylem and phloem in vascular bundles
-some of these stems are hollow

LEAVES

Leaves:
function:
-make sugar for the plant

structure:
-use diagram on p. 537
cuticle:
-waxy waterproof layer around leaf
mesophyll:
palisade mesophyll layer:
-photosynthetic cells stacked together to catch light at top of leaf
spongy mesophyll layer:
-photosynthetic cells spread out for gas exchange
stomata:
-hole in lower part of leaf for gas exchange, opened by guard cells

monocot leaves:
-parallel veins
dicot leaves:
-veins branch off central vein

VASCULAR TRANSPORT

xylem:
-dead cells which move water and dissolved nutrients up from the roots

-transport in xylem is explained by three theories
capillary action:
-adhesion (attraction of unlike particles) allows the water to stick to the xylem
-cohesion (attraction of like particles) allows other water to follow water up the xylem
root pressure:
-roots have low water concentration relative to soil
-osmosis occurs moving water into the root
-water then moves up the stem which also has low water concentration
transpiration pull:
-leaves lose water by transpiration (water loss through stomata)
-transpiration results in low water concentration in leaves relative to the stem
-osmosis occurs pushing water into the stem
-then water moves into the stem from the roots by osmosis
-then water moves from the soil into root by osmosis

phloem:
-live cells which move sugar down from the leaves

-transport in the phloem is explined by one theory
pressure flow:
-cells in leaves carry out photosynthesis now they have a high concentration of sugar
-these cells now have a low concentration of water relative to their neighboring cells
-water enters these cells by osmosis, forcing some of the sugar out into the next phloem cell
-the next phloem cell now has a reduced concentration of water
-this results in a continuation of the process of water into cells and sugar out
-sugar moves down the phloem

Draw a cross section of a monocot and dicot leaves using microscope slides and p. 537

Seeds:
-embryo in a shell containing food for the new plant
structure:
seed coat:
-protective shell
embryo:
-young plant containing three parts
    epicotyl:
-develops into leaves and top of stem)
    hypocotyl :
-develops into bottom of stem, top of root)
    radicle:
-develops into root
endosperm: food for the young plant
cotyledon: first seed leaf which shrivels and drops of in early development

monocots seeds:
-have endosperm and one cotyledon (seed leaf)
eg. corn
dicot seeds:
-have all the endosperm absorbed into two cotyledons
eg. bean

label monocot and dicot seeds using p. 562, figure 17.10

-seeds are dormant plants and can last years before germination
-germination requires heat, moisture, oxygen, some need light, fire (pine cones), cold (acorns)

fertilizer packages usually indicate the amount of N-P-K
-N helps with green growth on lawns, shrubs
-P helps grow roots, form flowers
-K helps plant hardiness, for survival in late autumn/winter
-vegetables need the same amount of all three

-do "discovery" activity on p. 560, choosing fertilizers

Desert:
-cactus have needles as leaves (low surface area, protective, no photosynthesis)
-cactus stem is green for photosynthesis and is thick to store water
-desert plants grow quick during rain, flower and seed in weeks
-seeds survive until next rain
-roots are very good at absorbing available water
Wetlands:
-carry out respiration well with surface parts (eg. water lily)
-often have hollow stem to carry oxygen
-seeds often float
Fire:
-makes soil better for new growth (with burned plants acting as fertilizer)
-some seeds germinate in extreme heat, allowing them to take advantage of the lack of competitors
Cold:
-flowers may be used to heat ovary of plant by concentrating light
-ovary matures quickly in short growing season
-deciduous trees reabsorb chlorophyll and drop leaves, nutrients moved into roots via sap
-sap flows into new leaves in spring
-evergreens have needle leaves to reduce surface area for water loss
Nutrient Poor:
-may eat animals for nutrients
eg. venus fly trap
-may act as parasites on other plants
eg. mistletoe
Shade:
-may bloom early spring on forest floor
eg. trilliums
-roots store energy underground
-life cycle occurs before canopy forms on forest

Plant Hormones:
-chemical messages in the plant (3 main groups)
Auxins:
-produced from the tip of the stem when exposed to light, causes cell elongation
-move down the side of the plant away from light, the stem bend towards light
-roots use auxin to inhibit elongation and as auxin goes to unlit cells
-the lit cells will elongate, allowing the root to grow down
-buds produce auxin to slow other bud growth (apical dominance)
-buds without much auxin are found in bushes (no dominant bud)
-auxins prevent the formation of abscission layers which cause leaves to fall off
-artificial auxins cause dicots (not monocots) to grow themselves to death
-used as a defoliant (eg. agent orange: causes health problems in humans)
Gibberellins:
-produced in apical meristems and leaf chloroplasts
-work with auxins to promote elongation of stem and root
-promote leaf growth, flowering, germination and fruit growth
-used commercially to promote fruit growth
Cytokinins:
-produced in the roots, promote cell division and differentiation
-slows aging
-used to preserve flowers commercially

Other chemicals:
absorbic acid:
-inhibits growth
ethylene:
-ripens fruit
-is chemically inhibited to preserve green fruit during transport to market

-use encyclopedias to complete the chart on plant source and medical use of the following:
-antihistamines
-atropine
-cocaine
-codeine
-digitalis
-estrogen (yams)
-morphine
-quinine
-reserpine

organ	function
leaf	-photosynthesis
stem	-support
root	-absorb nutrients
flower	-reproduction

tissue	example	function
MERISTEMATIC	vascular cambium	-increase width of plants
	apical meristem	-increase length of stem and roots
PROTECTIVE	epidermis	-living outer layer prevents water loss
	cork	-dead tissue covering surface of woody plants
VASCULAR	xylem	-dead cells move water and dissolved material from root
	phloem	-living cells move sugar from leaves
FUNDAMENTAL	parenchyma	-unspecialized cells in fruit and leaves
	collenchyma	-long thick support cells
	sclerenchyma	-support/protective

ROOT TYPE	DESCRIPTION	EXAMPLE
Tap	-longest root is the primary root	dandilion
Fibrous	-many roots of equal size	carrot
Adventitious	-roots come from middle of stem	ivy

stem	description
herbaceous monocot	-vascular bundles are scattered
herbaceous dicot	-vascular bundles are in a ring -vascular cambium between xylem and phloem

macronutrient	function
N	-fixed by bacteria to make nitrate -needed for DNA, RNA, protein
P	-needed for DNA, RNA
K	-helps stomata open -needed for water intake in root
Ca	-needed for cell walls
Mg	-part of chlorophyll

micronutrient	function
Fe	-needed for cellular respiration
Cu	-needed for cellular respiration
Zn	-part of chlorophlast