Question

When an unripe banana is sealed in a polythene bag, it remains green for many days. But if an apple is also sealed in the same bag the banana ripens and turns yellow within a few days. The reason is that apple
A.Removes $O_2$ released by the banana and thus promotes ripening
B.Produces $CO_{2}$ promotes ripening
C.Removes $CO_{2}$ which inhibits ripening
D.Releases ethylene which promotes ripening

Answer 1

Plant hormones also called phytohormones are the intrinsic factors or hormones that regulate the growth and development of the plants. These are auxins, gibberellins, cytokinins, abscisic acid and ethylene gas. These are present in low concentration and play an important role in cell division, seed germination, phototropism, dormancy, vernalisation, ripening etc. They can be promoters like auxins, gibberellins, cytokinins or inhibitors like abscisic acid or both inhibitors and promoters like ethylene based on their action.

Complete answer:
Option A- Removes $O_2$ released by the banana and thus promotes ripening
Oxygen released by the banana within the bag doesn’t cause ripening of the apple.

Option B- Produces $CO_{2}$ which promotes ripening
Production of carbon dioxide alone within the bag doesn’t cause ripening of fruits.

Option C- Removes $CO_{2}$ which inhibits ripening
Removal of carbon dioxide within the bag doesn’t inhibit the ripening of fruits.

Option D- Releases ethylene which promotes ripening
The apple along with the banana produces ethylene gas which will cause increased levels of ethylene within the polythene bag. Since ethylene gas is known as the fruit ripening hormone, acceleration of fruit ripening takes place due to the accumulation of ethylene gas at high levels.

Hence the correct answer is OPTION(D)

Note: Ethylene as a plant hormone occurs in gaseous form. It is produced by ripening fruits and tissues undergoing senescence. It not only helps in the ripening of fruits but also in seed germination, growth of shoot and root, promotes senescence, stimulates the reproductive part in plants etc. it is used in agricultural industry due to its functions, also used to increase production of fruits by increasing the production of female flowers and helps in early germination of seeds etc.