question_answer 31)

  From among the situations given below, choose the one that prevents both autogamy and geitonogamy. (a) Monoecious plant bearing unisexual flowers.                              (b) Dioecious plant bearing only male or female flowers. (c) Monoecious plant with bisexual flowers. (d) Dioecious plant with bisexual flowers.

Answer:

                  (b) Autogamy is a method of self-pollination in which the transfer of pollen grains from anther to stigma of the same flower takes place. While geitonogamy, is the transfer ofpollen grains from anther to stigma of another flower of the same plant.In the above condition, dioecious plants (bearing only male or female flowers) prevent both autogamy and geitonogamy. Geitonogamy is ecologically cross- pollination which is supposed to be equivalent to self-pollination because all flowers on a plant are genetically identical.