Plant Structure and Function

Make own energy from light

• First land pants
• Ex: moss
• Live close to water
• Non Vascular

• Protective waxy cuticle to prevent dessication
• Flagellated sperm that can swim in droplets of water to female
• Stomata

All plants alternate between haploid and dipliod

Have vascular tissue (xylem ad pholem)

• Naked seeds
• Vascular tissue
• Not true fruits (do not have endosperm)

• Flowering plants
• Double fertilization to create endosperm and nourish plant enbryo

• One Cotyledon (Seed leaf)
• Narrow leaf shape
• Leaf veins are parallel
• Vascular bundels in stems are throughout/random
• Fibrous roots
• ex: grasses

• Two Cotyledon (seed leaf)
• Broad leaf shape
• Leaf veins are branched
• Vascular bundles in stems are around edges
• Taproot system

Provide most photosynthesis to plant

Support to soil, provide minerals and water

hold Leaves to light and convery nutrients and water to leaves and roots

• Increase SA of roots to absorb water and nutrients
• Symbiotic fungi can also help uptake of water and nutrients

N2 fixing Rhizobium form symbiosis with root nodules

• Openings that allow diffusion of CO2, O2, and water vapor
• Size is controlled by guard cells

• Pal- Densely pack photosynthetic layer 
• Spongy- contains chloroplast with air spaces around cells, air spaces increase gas exchange

• Control size of stomata
• Open by day to allow CO2 exchange for photosynthesis
• Closed by night to limit transpiration
• More water in plant, guard cells swell and open allowing transpiration
• Less water in plant, guard cells shrink and clam shut
• Absorb water in response to K+ ions entering cells, sunlight causes K+ channels to open, triggered by light receptors

Evaporation of water from leaves that draws water up through plant

Pressure water exerts on cells

Self renewing population of cell that divide and cause plant to grow in height and width

Exist at tips of roots and stems

• Also called Cambium
• Are in stem between xylem and phloem
• Increase trunk size

At apical meristems, upwards

Outward at lateral meristems

• Plant hormone associated with growth
• Responsible for phototropism, geotrophism
• Terminal bud auxins travel down plant and prevent the formation of lateral buds that would be shaded by the top buds
• Stimulate production of new xylem by cambium

• Usually in stems
• Gravity increases concentration of auxin on lower side of horizontally turned plant (stem) 
• Lower side being to grow faster due to auxins and plant stems again is vertical and growing upwards

• Usually in roots
• Horizontally turned root  have a higher concentration of auxins in bottom
• Here they prevent growth
• Top of root beings to grow faster forcing horizontal section down into ground

• Plant hormone that stimulates stem elongation, especially on plants that don't grow especially tall 
• Inhibits formation of new roots
• Stimulates production of new phloem cells by cambium
• Terminate dormancy of seeds

• Promote cell division
• Ratio of cytokinins to auxins is important in differentiation of buds and roots
• More auxins, more roots
• More Cytokinins, more buds

• Stimulates the ripening of fruit and loss of leaves during seasonal changes
• Ethylene gas is used in the food industry to ripen unripe fruit for market
• Ethylene inhibitors are important in winter so that plants do not produce fruit and waste energy on something that will die

Cytoplasmic compartment made of continuous plasmodesmatea

Membrane on central vacuole

• Vascular tissue that contains column of water from roots to leaves
• Leaves regulate transpiration, and water mores up vis root pressure and cohesion of water

Pushes water up from roots, works best in short plants and humid environments where lots of water pools in the ground

• At day transpiration evidence (water on leaves) evaporated
• at night creates dew

• Water molecules tend to stick together because of high polarity 
• Transpiration happens because lower concentration of water in the air, pulls water up and out of plant

• Vascular tissue that contains sugars
• Much thinner walled then xylem
• Outside edge of stems
• Starts in leaves, where photosynthesis produces glucose, and moves down plant due to water potential
• Creates osmotic potential that pulls more water into pholem and forces sap down phloem

CHNOPS

FE, MG, Cl, Cu, Mn, ZN

H+ ions are able to knock cations free of soil particles so they an be absorbed by root hairs

• Nitrogen cannot be used with out nitrogen fixing bacteria 
• Needed for DNA
• Plants can use NH4, NO3
• Most plants use nitrate preferentially over ammonium (NH4)

Primary root