Q. Leaf abscission is caused by

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Solution:

Abscission is the fall of leaves and fruits. Addicott and his coworkers (1964) observed abscisic acid (ABA), a stress hormone, accelerated leaf abscission in cotton plants. Since, then it is believed that cause of abscission is the presence of growth inhibiting hormone (ABA), but its universal role for abscission is yet to be established.