Plant Form and Function
What are the two main systems that make up the plant body and their purposes?
Bonus: what three traits do they have in common?
root system - anchors plant, takes in water and mineral nutrients
shoot system - harvest light energy and CO2
Bonus: high surface area to volume ratio, indeterminate growth, and phenotypic plasticity
What two components make up water potential, and in what direction is water drawn?
solute and pressure potential
drawn towards lower potential
What type of tissue can be used to regrow a whole plant through vegetative reproduction?
meristematic tissue
What are the three ways plants respond to different stimuli?
phototropism - light
gravitropism - gravity
thigmotropism - touch
What aspects are considered when determining leaf shape and substructures?
area for photosynthesis, damage from wind and rain, water loss from evaporation
What is the cohesion-tension hypothesis?
water passively moves up through xylem by transpiration and cohesion down water potential gradient
What parts must a flower contain to be considered complete?
carpel, stamen, petal, and sepal
What are the 5 major hormone classes and their main functions?
auxins - elongation regulation
cytokinins - cell division
gibberellins - growth stimulation
abscisic acid (ABA) - growth inhibition
ethylene - ripening and cell death
What are the four specialized adventitious anchor roots we discussed and their purposes?
Pneumatophores - aid gas exchange
Prop roots - prevent top-heavy plants from toppling
Aerial roots - stabilize or absorb water in high surface water areas
Storage roots - store energy long term
What two routes did we discuss for water acquisition through roots, and what do they entail?
Bonus: which route gets interrupted, by what, and for what purpose?
apoplastic - travels through the cell wall, does not enter the cell, carries substances, does not go through a membrane
symplastic - travels through cytosol of cells using plasmodesmata, requires going through a membrane
Bonus: apoplastic, casparian strip, to filter out any toxic substances
How do plants differ as a result of their pollination method?
pollinator - bright colors and big smells
wind - higher sperm count
What do seeds use to determine the level of light competition?
red/far-red ratio
What are the three different types of ground tissues, and are they dead or alive at maturity?
parenchyma - alive
collenchyma - alive
sclerenchyma - dead
What three primary macronutrients are most commonly supplemented using fertilizer?
nitrogen, potassium, and phosphorous
labelled as NPK on fertilizer
What mechanisms are used to reduce/avoid selfing in angiosperms?
being dioecious, have stamen and carpel mature at different times, self-incompatibility to recognize genotype
What 2 conditions must occur for the stomata to be open?
Bonus: is having stomata open an active or passive process?
blue light and lack of ABA
Bonus: active
How does the arrangement of the vascular tissue in roots and stems differ between monocots and eudicots?
roots - ring in monocots, central in eudicots
stems - scattered in monocots, ring in eudicots
How and why do plants form a symbiotic relationship with Rhizobium?
how - release flavonoid to attract rhizobium, rhizobium enters root hair and causes infection into cortex of the root, infection buds off into cortex cells, nodule forms to trap rhizobium inside root
why - bacteria can fix nitrogen for the plant while the plant offers protection and an oxygen-free environment for the bacteria
Describe the steps of alternation of generations, including the ploidy and division methods at each point.
Bonus: how are the steps modified for angiosperms?
sporophyte (2n) -> meiosis -> spore (1n) -> mitosis -> gametophyte (1n) -> mitosis -> gametes (1n) -> fertilization -> zygote (2n) -> mitosis -> sporophyte (2n)
Bonus: angiosperms facilitate double fertilization and are heterosporous
How do auxins elongate using proton pumps?
proton pumps lower pH outside cell, activates expansins, cleave cross-linked sugars, electrochemical gradient pulls in other ions, solute potential inside becomes more negative, water follows ions into the cell and expands