Question

Fill in the blank with a suitable term:
___ is the only example of phytohormone which occurs in gaseous form.

Answer 1

Phytohormone:

1. Plants secrete chemical substances that modify various growth and developmental aspects. These substances are called phytohormones. Examples- Auxin, gibberellin, cytokinin, abscisic acid, ethylene.
2. Phytohormones are required in very less quantities. They are synthesised in one part of the plant and move to their site of action by diffusion, xylem vessels, or phloem tissues.
3. Ethylene is a gaseous phytohormone. It stimulates the ripening of fruits. It is produced by ripened fruits and aging tissues of the plant. Ethylene produced in one part of the plant easily diffuses in the air thus exerting its effect on neighboring fruits/ tissues. Ethylene is used by merchants to promote the ripening of unripe fruits and vegetables after they have been transported and stored before being sold in the markets.

Final answer

Ethylene is the only example of phytohormone which occurs in gaseous form.