1. (a) Name the gaseous plant hormone.
Describe its three different actions in plants.
(b) Which hormone is known as stress
hormone in plants? Why? 2.Which experiment
demonstrates that growth stimulating
hormone is produced at the tip of coleoptile.
Answers
Answer:
gaseous hormone is ethylene
absisic acid is known as stress hormone
Answer:
1.a) ethylene
b) abscisic acid ABA
Explanation:
a) ethylene is a gaseous plant hormone. It's growth inhibitor. it is mainly concerned with the maturation and ripening of fruits. maximum synthesis of ethylene occurs during the ripening of fruits (like apples, bananas, melons)
physiological effects of ethylene :
*ethylene promotes th ripening of fruits
example:tomato apple, mango, bananas, etc.
*ethylene inhibits the elongation of stems and roots in dicot.
*ethylene hastens the senescence of leaves and flowers.
*ethylene stimulates the formation of abscision zone in leaves, flowers and fruits. this leads to the premature shedding.
*ethylene breaks the dormancy of buds, seeds and storage organs.
b) abscisic acid is a growth inhibitor which regulates the abscision and dormancy. it increases the tolerance of plants to various kinds of stress. so it is called as stress hormone.
