Question

In tissue culture, Differentiation of shoot is controlled by ……………
A. Light intensity
B. Temperature shock
C. Low Auxin and High CK $\left ( \text{High}\xrightarrow[Cyto]{Auxin}\text{Ratio}\right )$
D. None of the above

Answer 1

Hint: Cell differentiation is caused by genes or hormones, In tissue culture differentiation of shot is caused by phytohormone name as auxin and cytokinin. Cytokinin hormone regulates the cell division in plant shoot and root and it acts as plant growth hormone, which involves cell differentiation.

Complete answer:
For the shoot differentiation in the plant is controlled by low auxin and high cytokinin ratio of the hormone, both hormones are responsible for morphogenesis. Auxin promotes the root cell division along with low cytokinin, phytohormone necessary for growth promotion along with gibberellic acid hormone that promotes the growth of internodes in plants.

If the ratio of auxin and cytokinin remain same then it will form a callus, callus if the undifferentiated mass of a cell, which is not differentiated into organized tissue.

Hence, the correct answer is option (C).

Additional information:
> Light intensity: Light also affects the plant growth, by stimulating the production of various chemicals in the plant body, some plants are short-day plants called as winter plants and long day plants which are summer season plants. Duration of light influences the production of carbohydrate or food production. The plant also shows photoperiodic movement like a sunflower.

> Temperature shock: This factor influences the activity of plants when a plant does not get enough water from its environment so it is not able to regulate body temperature so it stops or reduces the transpiration, and shows temporary wilting and release stress hormone to regulate its activity.

Note: Plant hormones divide into two broad categories such as a plant growth promoter and inhibitors. Plants growth promoter hormones such as auxin, cytokinin, gibberellins and plant growth inhibitor hormones are as follows ethylene and abscisic acid.