Which of the following is essential for fruit ripening ?

Key Points

The following are plant growth regulators or phytohormones that control various developmental as well as physiological functions of a plant:

• Auxin -
  • It helps in cell elongation, growth and differentiation.
  • It is present mainly at the root and shoot apices.
  • It is responsible for the phenomenon of apical dominance, where the apical buds inhibit growth of lateral buds.
  • It results in increasing the height of a plant due to apical dominance.
  • It can also initiate root growth in stem cuttings.
  • It may also promote flowering and prevent early fruit drop.
• Cytokinin -
  • It is mainly associated with cell division and is present in regions of rapid cell division.
  • It helps to overcome apical dominance and promote lateral shoot growth.
• Ethylene -
  • It is a gaseous phytohormone produced in the tissues undergoing senescence.
  • It helps in fruit ripening and other senescence-related activities.
  • It breaks seed and bud dormancy to initiate germination in some species.
  • It also induces leaf epinasty under stress conditions.
  • The triple response of ethylene includes reducing rate of elongation, increasing lateral expansion and swelling of region below hook in seedlings.
• Abscisic acid -
  • As the name suggests, it helps in abscission and dormancy.
  • It inhibits plant growth, metabolism and seed germination.
  • It also plays an important role in closure of stomata under stress conditions.