Question

Do Plants Breathe?

Answer 1

Hint:Plants do not have respiratory and circulatory systems like animals do, wherein gases are carried all over their structures, however they play a key role in ensuring that carbon is taken up from the atmosphere as carbon dioxide.

Complete answer:
Plants do not breathe in the way that animals do. They don’t have lungs or a circulatory system that will carry oxygen all over the plant body. However, plants do need to take in and give out gases in order to survive and grow. During the day, as part of photosynthesis, plants take in carbon dioxide and give oxygen. Carbon dioxide and water are combined to produce storage carbohydrates. This intake and release of gases occurs through tiny holes on the surfaces of the leaves called stomata. Each leaf has thousands of these structures.

Stomatal opening and closing is not random. They do not stay open continuously but are regulated by two factors: light and water pressure. Light causes the stomata to open up, which is why they will be open during the day for the passage of gases and water vapour. However, if water pressure in the plant drops, the stomata then close so that water is not lost during transpiration from these tiny openings.
Besides requiring carbon dioxide, plants take in oxygen as well for their various metabolic processes and the generation of energy. Oxygen diffuses in through the stomata and passes down the gradient of high oxygen concentration to areas with low oxygen concentration.

Note:The cells bordering the stomata are known as guard cells, and each stomatal opening has two guard cells. When water pressure is high, turgidity in these cells causes the inner edge of the cells to pull apart opening the stomata, and vice versa.