Lecture 9 - Energy Balance in Plants Flashcards
epidermis
production of root hairs, which project into the soil increasing surface for water and nutrient uptake
what are 2 of the pathways that water moves from the soil to xylem
symplast and apoplast
suberin
cell wall-associated biopolymer found in the endodermis
water moves from areas of ____ water potential to areas of ______ water potential
high, low
what location can you expect the highest water potential in plant roots
root epidermis (might be wrong)
what is hydropassive response
close stomata
a plant in drought generates _____ solute potential to cause more water to move into the plant
low
the solute potential is _____ when solutes are added to an aqueous system
reduced
2 main drought mechanisms that affect turgor pressure
elastic adjustment
osmosis adjustment
modes of energy exchange
conduction
convection
latent heat transfer
radiative exchange
conduction
individual molecules transfer kinetic energy from one to another but they do not move far in the process
convection
individual molecules gain kinetic energy from one region and themselves transfer it to another region
latent heat transfer
latent heat of vaporization (amount of energy needed to change from liquid to vapor)
what other mode of energy exchange does latent heat transfer use
kinetic energy to allow molecules to escape H bonding at the air-water-interface and vaporize
radiative exchange
all matter acts as a near-perfect black body that absorbs and emits all radiant energy
Basically the amount of energy emitted/reradiated from a body
high temperatures have ____ wavelengths and ____ emissivity energy
short, strong
low temperatures have _____ wavelengths and ______ emissivity energy
long, weak
where does the leaf get its energy input
radiant energy from the sun
different kinds of energy inputs and where they come from
short wavelengths for sun
long wavelengths from soil and air
conduction in leaves
direct transfer of heat energy from leaf to surrounding atmosphere: boundary layer
transpiration
evaporation of water mainly through the stomata of leaves
convection in leaves
transport of energy by volume of air/wind
different ______ can affect conduction and convection in leaves
leaf shapes
how can drought conditions affect photosynthesis
rates of photosynthesis can drastically decrease
what do spines function as in plants
reflectors and reradiators to reflect sun to reduce heat
if plants are under drought stress conditions, a new _______ equilibrium will be established at each leaf surface
thermal
