(b) Two similar green plants are kept separately in oxygen free containers, one in dark and the other in continuous light.

Question

(a) How do guard cells regulate opening and closing of stomatal pores ? 

(b) Two similar green plants are kept separately in oxygen free containers, one in dark and the other in continuous light. Which one will live longer ? Give reasons.

Answer 1

(a) The opening and closing of stomatal pores is controlled by the guard cells, when water flows into the guard cells, they swell, become curved and cause the pore to open whereas when the guard cells lose water, they shrink, become straight and close the stomatal pore. 

(b) Plant kept in continuous light will live longer because it will be able to produce oxygen required for its respiration by the process of photosynthesis.