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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

the resulting tension, from the stretching of air-water interfaces, in the xylem pulls water by -- from the roots

bulk flow