Question

Which plant hormone is found in gaseous form
a. Auxin
b. Cytokinin
c. Ethylene
d. ABA

Answer 1

Hint: The only plant hormone that is found in gaseous form helps in ripening of fruit. Farmers control the synthesis of this hormone by several physiological means and prevent the ripening of fruits. This hormone can also communicate with other plants via air.

Complete answer:
The plant hormones, which are also called phytohormones, are essential to plants as they perform several important functions of plants- like growth, flowering, phototropism, stem elongation, cell division, fruit ripening etc.

There are several types of hormones found in a plant. They are- auxin, cytokinin, ethylene, abscisic acid or ABA and gibberellins. All these hormones control various functions in plants. Among them only ethylene is found in gaseous form.

Hence, the option (c) Ethylene is the correct answer.

Additional Information:
Ethylene hormone can be produced from almost any part of the plant. The hormone ethylene is mainly associated with the ripening of fruits. Ethylene also travels outside the plant by diffusing through the plant tissue into the air and can affect a totally different plant.

> The option (a) Auxin is the hormone that is associated with the growth of the plant. The plant produces auxin naturally in order to grow and survive.

> The option (b) Cytokinin is a type of hormone that is produced at the apical part of the root or at the root tip. They travel up the shoot with the help of xylem. They help in controlling the cell cycle of the pants. They also help in repairing any damage of the plant.

> The option (d) ABA or abscisic acid is also an essential type of hormone found in plants. It controls the water stress in plants. They send chemical messengers to the affected or stressed area and act accordingly.

Note: Along with the fruit ripening, the ethylene helps in rapid diffusion, it also helps in oxygen transportation and also controls stem elongation and flowering. The synthesis of ethylene can be inhibited by carbon dioxide and hence the ripening can also be controlled by this. Slowing down the ripening process of fruits is sometimes practiced by farmers when large scale manufacture and export of fruits are carried out between two distant countries.