Test: Auxin and Tropism - JAMB MCQ

Tropism refers to the growth or movement of a plant in response to a specific stimulus, such as light (phototropism) or touch (thigmotropism).

Phototropism is the growth or movement of a plant in response to light. It allows plants to orient themselves towards a light source for optimal photosynthesis.

Thigmotropism is the growth or movement of a plant in response to touch or contact with a solid object. It helps plants to respond to physical stimuli in their environment.

Gravitropism is the growth or movement of a plant in response to gravity. It enables the shoots to grow upward and the roots to grow downward, allowing the plant to establish a proper orientation.

Auxin, a plant hormone, is primarily responsible for phototropism. It accumulates on the shaded side of the plant and promotes elongation, causing the plant to bend towards the light source.

Auxin inhibits the growth of roots, allowing shoots to grow more rapidly. This differential growth response helps in maintaining the proper orientation of the plant.

Auxin promotes cell elongation on the illuminated side of the plant, causing it to bend towards the light source. This differential growth results in phototropism.

Auxin plays a significant role in gravitropism. It accumulates on the lower side of the plant in response to gravity, promoting cell elongation and growth, which causes the roots to grow downward and shoots to grow upward.

Geotropism, also known as gravitropism, is primarily regulated by auxin but is also influenced by ethylene. Ethylene plays a role in coordinating the overall response of the plant to gravity.

Auxin promotes cell elongation on the side opposite to touch, allowing the plant to bend or curl away from the stimulus. This response is responsible for thigmotropism in plants.