Question

increase in stress tolerance in plants, thats why, it is also known as stress hormone."

Answer 1

adrenaline

Hope it helps..

Answer 2

Abscisic acid (ABA) is also known as stress hormone in plants due to following reasons

1. In case of stress i.e. water shortage, it causes closing of stomata thus preventing loss of water from the plant.

2. During unfavorable conditions such as food shortage or harsh environmental conditions, it causes dormancy in seeds and promotes seed development when the conditions become favorable.

3. It also promotes abscission of leaves, stems and flowers.