Exam 2 Flashcards
dodder
-parasitic plant with pale stems and piglike haustoria
mutualism
both species benefit
commensalism
1 benefits, other is unharmed
parasitism
-1 is benefited, other is harmed
mycorrhizae
-fungi that is grown in association to roots
-fungus gets sugars from host and plant gets additional water and nutrients
-85-90% of plants have this association
ectomycorrhizae
remain outside of plant cells
endomycorrhizae
-more common
-grow inside plant cells
rhizobium
-bacteria that grow in association with roots of pea plants
-help with nitrogen fixation
human relevance of roots
spices, dyes, insecticides, drugs
cuticle
-made of cutin
-in upper epidermis of leaf
-prevents water loss and bacterial infection
palisade mesophyll
-site of photosynthesis
-tall columnar cells
spongy mesophyll
-photosynthesis, air spaces between cells
lower epidermis
-guard cells that form stomates
-allows diffusion of co2 into leaf and o2 out of leaf
bulliform cells
-in grasses, influence leaf expansion
sun leaves
-multiple palisade cell levels
-thicker leaf
-more photosynthetic material
shade leaves
-thinner
-fewer palisade cells and spongy mesophyll
compass plant
-leaves are oriented to east and west and are perpendicular to ground (not directly hit by sunlight)
barberry spines
modified leaves
flower pot leaf
opened up and has roots inside
floral leaves
-brachts
-colorful to attract pollinators to non-ornamental flowers
carnivorous plants
-most environments with acidic ph soil with low nutrient content
types of pigments
-carotenoids: yellow
-anthocyanin: red
-chlorophyll: green
carotenoids
carotene and xanthophyll
what happens during fall to chlorophyll
chlorophyll breaks down and plant stores mg from it
-this exposes carotenoids
abscission
process by which leaves are shed in fall by deciduous trees
human use of leaves
-mint, shade, food, dyes, fibers, medicine, tea
why do plants need water
-young cells can be 90% water
-enzymatic processes and other chemical reactions
-photosynthesis
-mesophyll cell surfaces must be moist for co2 to diffuse into cell
-cell turgor
osmotic potential of a solution
-a measure of the potential of water to move from one cell to another as influenced by solute concentration
-turgor pressure (pressure potential): pressure of cell contents against cell wall as a result of water entering vacuole
water potential
=osmotic potential + pressure potential
transpiration
-water enters air by way of leaf by transportation
-90% of water entering plant passes through and evaporates
-only 5% is lost through cuticle
pathway of water through plant
soil
root
xylem in root
xylem in stem
leaf (water used in mesophyll for photo.)
cohesion
-water flows from less negative to more negative potentials
-or from higher water potential to lower water potential
guard cells and stomate in transpiration
-change in turgor pressure when exposed to changes in light, co2, and water conc.
active transport of k+
-k+ pumped into vacuole while guard cells photosynthesize
-atp produced via respiration of sugars
-k+ leaves cell when guard cells stop photosynthesizing
stomate response to water stress
-close when water stress occurs
-abscisic acid is produced in leaves subject to water stress causing membrane leakages from cells
-k+ ions leave guard cells, water follows and cells deflate