Grand Challenges: Water

Question 1

Controls of water use

Answer 1

Waxy layers - prevent loss
Stomata - open and close; open for CO2, close to stop water loss; need some transpiration; open too long = too much water loss

Question 2

Guard cells

Answer 2

Increase turgor pressur to bow outwards to open pore
High light = open
Low CO2 = open
Water stress = close

Question 3

Stomatal differentiation

Answer 3

Leaf decides how many pores to make as it develops
More pores = more potential CO2 and more water loss

Question 4

Sequence of gene expression patterns

Answer 4

Conserved sequence of expression patterns of genes regulate differentiation of epidermal cells into stomata
Peptide signals tell cells what neighbours should do
Env factors control tf
Tf determine how many stomata in baby leaf

Question 5

Density and stomata number

Answer 5

Impacts functional outcome on rate of water loss
Fewer stomata has better water use efficiency but may not get as much yield; more drought tolerant

Question 6

Transgenic barley

Answer 6

Higher yields in transgenic plants w low stomatal density when under drought stress

Question 7

Opening and closing of stomata

Answer 7

Photosynth turns on and off quick
Opening and closing of stomata much slower
Alter physical properties and pressure to get it to open faster
Modify polymers - sets mechanical properties of tissue
Shift system so less pressure required to open - larger aperture for same pressure

Question 8

Consequences on rest of leaf

Answer 8

Alters transpiration rate on leaf surface