Question

What are their physiological effects of Abscisic acid in – plants and its role in agriculture?

Answer 1

Physiological effects:

• It helps in reducing transpiration rate by closing stomata. It inhibits K+ uptake by guard cells and promotes the leakage of malic acid. It results in closure of stomata;
• It spoils chlorophylls, proteins and nucleic acids of leaves making them yellow.
• Inhibition of cell division and cell elongation.
• ABA is a powerful growth inhibitor. It causes 50% inhibition of growth in Oat coleoptile.
• It induces bud and seed dormancy.
• If promotes, the abscission of leaves, flowers and fruits by forming abscission layers.
• ABA plays an important role in plants dtiring water stress -and during drought conditions. It results in loss of turgor and closure of stomata,
• It has anti-auxin and anti-gibberellin property.
• Abscisic acid promotes senescence in leaves’ by causing loss of chlorophyll pigment decreasing the rate of photosynthesis and changing the rate of proteins and nucleic acid synthesis.

Agricultural Role:

• In Cannabis sativa, induces male flower formation on female plants.
• Induction of flowers in short day plants.
• It promotes sprouting in storage organs like Potato.
• ABA plays an important role in plants during water stress drought conditions.
• It inhibits the shoot growth and promotes growth of root system. This character protect the plants from water stress. Hence, ABA is called as stress hormone.