PMB 5412 Exam 1
Plant physiology - ANS-the study of plant function and behavior, encompassing all the
dynamic processes of growth, metabolism, reproduction, defense, and communication
that account for plants being alive
What are the properties of water that are important for plants? - ANS-Polar with positive
and negative charged poles; good solvent; high latent heat for vaporization; cohesion,
adhesion and surface tension for capillarity.
How water moves within plant cells? - ANS-Diffusion; Fick's law
Fick's law - ANS-describes the movement of water by diffusion
What is water potential, and how does it determine many cellular processes in plants? -
ANS-Yw = Ys + Yp + Yg
Water potential - ANS-a measure of the free energy associated with water per unit of
volume (J m-3)
Solute potential (osmotic potential) - ANS-the effect of dissolved solutes on Yw
Pressure potential - ANS-the hydrostatic pressure of a solution relative to atmospheric
pressure, which is 0 for the solution in an open container
Gravitational potential - ANS-the water potential caused by gravity
Field capacity - ANS-water content of a soil after it has been saturated and excess
water allowed to drain away
wilting point - ANS-can be determined experimentally as the soil water content below
which most plants (e.g., wheat or maize) cannot recover from wilting
The key factors that determine water movement in the soil? - ANS-Bulk flow; pressure
differences and particle size
Yp= -2T/r (T=surface tension)
Yp answer is in MPa
, The key pathways for water uptake by the roots? - ANS-Apoplast, symplast and
transmembrane. Casparian strip forces H2O through transmembrane pathway as a
filter.
The key components for water transport through xylem? - ANS-pressure-driven bulk
flow; hollow dead cells with high conductivity; secondary cell walls provide structural
support; Preventing cavitation is critical.
Water evaporation (transpiration) from leaf to air create... - ANS-negative pressure
potential to drive the water transport in plants
Gas (H2O and CO2)... - ANS-exchanges through stomata
Guard cells regulate... - ANS-the stoma opening and closing through ion exchanges
Water cross cell membrane through... - ANS-aquaporins (membrane-bound water
channels)
Engineering plants for better WUE by... - ANS-manipulating photosynthesis pathways,
root architectures, and stomata density
Potometer - ANS-can be used to measure the rate of transpiration that's proportional to
water uptake
The most abundant mineral element in a plant - ANS-Nitrogen
Nitrogen forms in soil - ANS-ammonium NH4+, and nitrate NO3-
Nitrogen functions in the plant - ANS-constituent of proteins and nucleic acids,
chlorophyll
Nitrogen forms in the plant - ANS-NO3-, amino acids and other organic N
Nitrogen deficiency - ANS-MOBILE
general chlorosis (light green) primarily in older leaves - N is mobile in the plant.
Phosphorus forms in soil - ANS-H2PO4- to HPO42-
Phosphorus functions in the plant - ANS-structural component of nucleotides,
phospholipids, ATP, DNA, RNA
Plant physiology - ANS-the study of plant function and behavior, encompassing all the
dynamic processes of growth, metabolism, reproduction, defense, and communication
that account for plants being alive
What are the properties of water that are important for plants? - ANS-Polar with positive
and negative charged poles; good solvent; high latent heat for vaporization; cohesion,
adhesion and surface tension for capillarity.
How water moves within plant cells? - ANS-Diffusion; Fick's law
Fick's law - ANS-describes the movement of water by diffusion
What is water potential, and how does it determine many cellular processes in plants? -
ANS-Yw = Ys + Yp + Yg
Water potential - ANS-a measure of the free energy associated with water per unit of
volume (J m-3)
Solute potential (osmotic potential) - ANS-the effect of dissolved solutes on Yw
Pressure potential - ANS-the hydrostatic pressure of a solution relative to atmospheric
pressure, which is 0 for the solution in an open container
Gravitational potential - ANS-the water potential caused by gravity
Field capacity - ANS-water content of a soil after it has been saturated and excess
water allowed to drain away
wilting point - ANS-can be determined experimentally as the soil water content below
which most plants (e.g., wheat or maize) cannot recover from wilting
The key factors that determine water movement in the soil? - ANS-Bulk flow; pressure
differences and particle size
Yp= -2T/r (T=surface tension)
Yp answer is in MPa
, The key pathways for water uptake by the roots? - ANS-Apoplast, symplast and
transmembrane. Casparian strip forces H2O through transmembrane pathway as a
filter.
The key components for water transport through xylem? - ANS-pressure-driven bulk
flow; hollow dead cells with high conductivity; secondary cell walls provide structural
support; Preventing cavitation is critical.
Water evaporation (transpiration) from leaf to air create... - ANS-negative pressure
potential to drive the water transport in plants
Gas (H2O and CO2)... - ANS-exchanges through stomata
Guard cells regulate... - ANS-the stoma opening and closing through ion exchanges
Water cross cell membrane through... - ANS-aquaporins (membrane-bound water
channels)
Engineering plants for better WUE by... - ANS-manipulating photosynthesis pathways,
root architectures, and stomata density
Potometer - ANS-can be used to measure the rate of transpiration that's proportional to
water uptake
The most abundant mineral element in a plant - ANS-Nitrogen
Nitrogen forms in soil - ANS-ammonium NH4+, and nitrate NO3-
Nitrogen functions in the plant - ANS-constituent of proteins and nucleic acids,
chlorophyll
Nitrogen forms in the plant - ANS-NO3-, amino acids and other organic N
Nitrogen deficiency - ANS-MOBILE
general chlorosis (light green) primarily in older leaves - N is mobile in the plant.
Phosphorus forms in soil - ANS-H2PO4- to HPO42-
Phosphorus functions in the plant - ANS-structural component of nucleotides,
phospholipids, ATP, DNA, RNA
