question_answer 63)

    The opening and closing of the stomatal pore depends upon (a) oxygen                                          (b) temperature               (c) water in guard cells                                                   (d) concentration of CO2 in stomata

Answer:

                  (c) Large number of tiny pores called stomata are present on the surface of the leaves of plants. The gaseous exchange as well as transpiration takes place through these pores. The opening and dosing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomata pores to open. Similarly the pore closes if the guard cells shrink or losses water in them.