Flashcards in Class 3 Deck (112)
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1
simplest index of water status
relative water content
2
relative water content = -- / (saturated mass - dry mass) x 100%
fresh mass - dry mass
3
one weakness of RWC is that it is not very -- for measuring drought responses
sensitive
4
leaves can show strong responses to -- change in RWC
less than 2 percent
5
one weakness of RWC is that it tells us nothing about the -- for water movement
forces
6
-- is another index of water status, that is correlated with RWC but lacks RWC's weaknesses
water potential
7
an overall, average water potential of the whole leaf, as the collection of all the leaf cells
leaf water potential
8
leaf water potential can be measured with the --
pressure bomb
9
for leaves of well watered plants, leaf water potential ranges from --
-0.2 MPa to -2 MPa
10
plants of arid climates of saline environments can function at much lower leaf water potential down to below -- due to accumulating solutes in the cells, producing a very negative solute potential
-5 MPa
11
plant growth requires that cells have -- turgor pressure
positive (pressure potential > 0)
12
as cells lose water, pressure potential -- quickly until turgor is lost (solute potential declines linearly)
drops
13
T/F: as water potential declines further, different functions cease, and eventually plants die
true
14
at zero turgor, unlignified tissues collapse and plants --
wilt
15
plot of leaf water potential versus RWC
(or sometimes - 1/leaf water potential vs RWC, or vs 100%-RWC), and sometimes includes plots of leaf osmotic (solute) potential and pressure potential versus RWC
pressure-volume curve
16
plotting the PV curve allows extraction of 4 main parameters: the --, determined from the intercept of the solute potential versus RWC
osmotic potential at full turgor
17
osmotic potential at full turgor is an index of the -- of cell sap in hydrated tissue
saltiness
18
plotting the PV curve allows extraction of 4 main parameters: -- which is the leaf water potential corresponding to the point at which the pressure potential = 0 or when the leaf water potential = solute potential
osmotic potential at turgor loss point
19
osmotic potential at turgor loss point is also known as -- or simply turgor loss point
water potential at turgor loss point
20
because stomata close and cells may lose function at turgor loss, osmotic potential at turgor loss point is a -- of cell, leaf and plant drought tolerance
predictor
21
plotting the PV curve allows extraction of 4 main parameters: -- determined as the slope of pressure potential versus RWC
modulus of elasticity
22
modulus of elasticity is an index of the -- of cell walls
rigidity
23
some drought tolerant plants have -- elastic modulus values, but not always
high
24
plotting the PV curve allows extraction of 4 main parameters: -- is the x-intercept of the -1/leaf water potential versus RWC curve
apoplastic function
25
apoplastic function represents the -- in the apoplast in a hydrated leaf
% of water stored
26
of all the PV curve's parameters, -- is the strongest predictor of drought tolerance
osmotic potential at turgor loss point (water potential at turgor loss point, turgor loss point)
27
-- of cell sap is a strong predictor of drought tolerance across plant species
saltiness
28
water diffuses from the leaf due to a -- between leaf and air
water vapor concentration gradient (vapor pressure deficit)
29
the diffusion of water from the cell walls inside the leaf causes stretching of -- which generates a tension, pulling water from the xylem
air-water interfaces
30