BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The bending of the stem towards sunlight in plants is due to unequal distribution of auxin. Auxin hormone synthesized by meristematic cells at shoot tip moves from the tip of the stem and concentrates more on the side not receiving light or shady side.

Detailed explanation-2: -Auxin promotes cell elongation due to weakening of the cell wall combined with influx of water (which literally stretches the cells). Because the cell expansion occurs only on the shaded side of the stem, the plant bends away from the shade and toward the light.

Detailed explanation-3: -Under normal light conditions auxins are spread out in the plant. But when sunlight varies, auxin is broken down on the sunnier side of the stem. The higher concentration of auxin on the shady side causes the plant cells on that side to grow more so it bends toward the light.

Detailed explanation-4: -When light comes from an angle, plants will curve toward it to get better access to the light they need to grow. Hormones in the plant’s tissues, called auxins, make cells on the dark side of the plant grow taller, bending the plant toward the light.

Detailed explanation-5: -The bending of the plant towards light is known as phototropism. It is due to the plant hormone auxins. When the growing parts of a phototropic plant detect sunlight, auxins (synthesized at the shoot tips) help the cells grow longer.