question_answer 57)

  It is known that some varieties of wheat are sown in autumn but are harvested around next midsummer. a. What could be the probable reason for this? b. What term is used for this promotion of lowering under low temperature? c. Which plant hormone can replace the cold treatment? .

Answer:

                a. Annual winter wheat plants take one year full growing season for the completion of their vegetative growth period and then initiate flowers and fruits. This is because after they form seedlings in autumn, they receive low temperature throughout winter, which enables them to reach vegetative maturity. They resume growth- in spring and bear flowers and grains towards mid-summer. b. The chilling or cold treatment of seeds to reduce flowering is called vernalisation. It is a process of shortening of the juvenile or vegetative phase and hastening flowering by a previous cold treatment. This stimulus of vernalisation is perceived only by the meristematic cells, e.g., shoot tip, embryo tip, root apex, developing leaves, etc. c. GA or gibberellic acid treatment can replace cold treatment and can induce flowering early by reducing vegetative growth period in many long-day plants.