Stomatal regulation

Stomata are -

• leaf pores on the upper surface of leaves

• leaf pores that allow CO2 into leaves and H2O and O2 out

• leaf pores that allow CO2 out of leaves and H2O and O2 in

• leaf pores controlled by leaf chlorophyll

Stomatal opening can be measured -

• By weighing plants and recording water loss

• With a scanning electron micrograph

• using leaf peals, a porometer or leaf gas exchange

• Only in plants that have evolved less than 400 million years ago

ABA is

• a plant hormone involved in stress response

• also known as abscisic acid

• produced in roots and leaves

• all of these answers

ABA closes stomata by doing the following -

• K+ and Cl- accumulate outside the guard cell while Ca2+ accumulates inside the guard cell

• osmotic imbalance in and out of guard cells so water is drawn out of guard cells

• both of these

• none of these

Which of the following scenarios would have the highest stomatal conductance (most open stomata)?

• high light, high CO2, absence of ABA

• low light, low CO2, presence of ABA

• high light, low CO2, absence of ABA

• high light, high CO2, presence of ABA

When stomata close, photosynthesis declines because

• there is less water going into the plant

• there is less water going out of the plant

• There is less light going into the plant

• There is less CO2 going into the plant