Question

What are tropic movements in plants? Why does the shoot of the plant bend towards the light when it is kept in a cardboard box with a small hole on one of its sides?

Answer 1

Hint: Tropic movements in plants indicate the growth or existence of a plant organism in response to an environmental stimulus. Most plant shoots show positive phototropism and regroup their chloroplasts within the leaves to maximize photosynthetic energy and promote growth.

Complete answer:
In tropic movements, the response is dependent on the direction of the stimulus such as light, gravity, temperature, chemical substances, water, etc. Tropic movements are normally named for the stimulus involved, for example, a phototropism is a response to sunlight, it may be either positive (towards the stimulus) or negative (away from the stimulus). Tropisms occur in three sequential steps. First, there's a sensation to a stimulus, which is typically beneficial to the plant. Next, signal transduction occurs. And finally, the directional growth response occurs.
The shoot of the plant bends towards the light when it is kept in a cardboard box with a small hole on one of its sides, this happens due to phototropism. Phototropism is the growth of an organism in response to a light-weight stimulus. The cells on the plant that are farthest from the sunshine have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one among the various plant tropisms or movements which answer external stimuli. Growth towards a light source is named positive phototropism, whereas growth far away from light is named negative phototropism.

Note: Tropic movements in emerging shoots, comprising the tendencies for the stalk to grow towards the light (phototropism) and the roots to grow downward (gravitropism). In both cases, the directional growth is taken into account to flow from to asymmetrical distribution of auxin (a plant growth hormone). Also, the areas on the dark side of the plant will have more auxin, which means that they will have long, stretchy cells.