question_answer 58)

  Name a hormone which a. is gaseous in nature b. is responsible for phototropism c. induces femaleness in flowers of cucumber d. is used for killing weeds (dicots ) e. induces flowering in long day plants.

Answer:

                a. Ethylene is a hormone which is gaseous in nature. b. Auxin (synthetic auxin 2-4 D) is responsible for phototropism and geotropism in plants. c. Ethylene causes feminising effect. External supply of very small quantity of ethylene can increase the number of female flowers and hence fruits as in cucumber. d. Synthetic auxin (2-4 D) kills broad leaved dicot weeds, hence used as weedicides. e. Gibberellins, induces flowering in long-day plants.