Question

Name the only gaseous natural plant hormone. Describe its three different kinds of action in plant.

Answer 1

Ethylene is the only gaseous natural plant hormone. It is produced in large amounts by tissues undergoing senescence and ripening fruits.

An action of Ethylene in plants are as follows

1) It was observed that unripe bananas ripened faster when stored with ripe bananas. Later, the substance promoting the ripening was found to be ethylene. It is highly effective in fruit ripening as it enhances the respiration rate during the ripening of the fruits.

2) Ethylene promotes Femaleness (Feminising effect) in Pineapple (Bromeliaceae) and Cucumber. It increases the number of female flowers in cucumber plants, thereby increasing the final yield.

3) Ethylene breaks seed and bud dormancy, initiates germination in plants.

4) It also promotes root growth and root hair formation, thus helping the plants to increase their absorption surface.