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