NEET BIOLOGY

Detailed explanation-1: -Phototropism is a directional response that allows plants to grow towards, or in some cases away from, a source of light.

Detailed explanation-2: -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-3: -When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light. Thus, the plant appears to bend towards light.

Detailed explanation-4: -Auxins function primarily in stem elongation by promoting cell growth. Indole-3-acetic acid (IAA) is the major naturally occurring auxin and one of the major growth factors in plants. They were the first group of plant growth hormones discovered. Auxins serve dual roles in plants depending on where they are produced.

Detailed explanation-5: -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.