Name the following:
A gaseous plant hormone which promotes ripening of fruits.
Topic: Ethylene
Answer
ETHYLENE (ethene).
Ethylene is the only plant hormone that is a GAS, which is what the question is pointing at with the word "gaseous". It hastens the ripening of fruits, and also promotes the falling of leaves and fruits.
PRACTICAL CONSEQUENCES worth knowing, because examiners like them: because it is a gas, it spreads from fruit to fruit — which is why one ripe fruit hastens the ripening of the rest in a basket, and why a rotting fruit spoils the others bananas and mangoes are picked green, transported, and then ripened artificially with ethylene at the market the traditional practice of ripening fruit in straw or by burning incense in a sealed room works because both release ethylene
It is also the reason calcium carbide is illegally used to ripen fruit, since it releases a gas that mimics ethylene.