07 Plant Growth and Mineral Nutrition - part 12 - Growth Harmone - Ethylene

07 Plant Growth and Mineral Nutrition - part 12 - Growth Harmone - Ethylene


Ethylene : 
  • It is the only gaseous growth regulator. 
  • Denny (1924) reported ethylene is effective in fruit ripening. 
  • Gane (1934) established that plants naturally synthesize ethylene. 
  • Crocker (1930) proposed that ethylene is the plant hormone responsible for fruit ripening. 
  • It is a simple gaseous hydrocarbon withessential role in the fruit ripening. 
  • The most widely used compound as a source of ethylene is ethephon. 
  • It is synthesized in roots, shoot apical meristem, ripening fruits etc.

Do you know ? 
  • Ethret / Ethephon is a 2-chloroethyl Phosphoric acid, which releases ethylene after dissolving in water.

Physiological effects and application of ethylene : 
  • Promotes ripening of fruits like bananas, apples and mangoes. 
  • Stimulates initiation of lateral roots in plants and breaks the dormancy of bud and seed. 
  • Accelerates the abscission activity in leaves, flowers and fruits by forming of abscission layer. 
  • Inhibits the growth of lateral buds and causes apical dominance and retards flowering.
  • Associated with the enhancement of process of senescence of plants organs. 
  • Inhibits flowering in most of the plants except pineapple. 
  • It causes epinasty (drooping) of leaves and flowers. 
  • Increases activity of chlorophyllase enzymecausing degreening effect in banana and Citrus fruits.

Degreening:
  • It is the process of decomposition of green pigment in fruits usually by applying ethylene. This method is called trickle degreening.

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