NEET BIOLOGY

Detailed explanation-1: -Heliotropic plants change the orientation of their leaves toward the sun. This solar tracking mechanism can occur as a continuous adjustment throughout the day so that the leaf blades are always oriented perpendicular to the sun’s rays.

Detailed explanation-2: -Heliotropism, or solar tracking, is when a plant follows the movement of the sun during the day. Rooted in ancient Greek, “helio” refers to the sun and “tropism” means a turning or movement of a living organism toward or away from an external stimulus, such as light, heat or gravity.

Detailed explanation-3: -Leaf movement The heliotropism displays two forms: (i) diaheliotropism (the leaf lamina becomes oriented at an angle perpendicular to the direction of light); and (ii) paraheliotropism (the leaf lamina becomes oriented at an angle parallel to the direction of light).

Detailed explanation-4: -phototropism. The correct option is A. Explanation for correct option: The movement of a sunflower occurs according to the direction of sunlight. This type of growth movement is called phototropism.

Detailed explanation-5: -Leaves and floral parts both exhibit heliotropism. Floral heliotropism is controlled by motor cells located just below the flower head. These cells move potassium ions between adjacent cells – drawing potassium in and expanding while in shade, and pushing potassium out and retracting in the sun.