How does gaseous exchange occur in plant?

Answer 1

Gas exchange can occur in several ways for most plants. The leaves and young stems of plants have openings in the epidermis controlled by guard cells. The openings are called stomata. Carbon dioxide from the atmosphere will diffuse through the stomata and oxygen diffuses out into the air. They are normally open in the day light and closed at night. Trees with bark may have spongy layers in the bark called lenticels allowing gas exchange. Gas exchange will occur through the moist epidermal layers of the young roots. Oxygen from the soil will diffuse into the cells while carbon dioxide diffuses out of the cells into the soil. Plants submerged in water will have gases diffuse in and out of the cells from the water. Cypress trees have "knees" for obtaining oxygen in water logged soils. The knees emerge above the water into the air.