Question

The main effect of cytokinin in the plant is
A.Improve the quality of fruits
B.Prevent the growth of lateral buds
C.Regulate closing and opening of stomata
D.Stimulate cell division

Answer 1

Hint: Cytokinin is a plant hormone that regulates plant growth. The regions where cytokinin found in plants are root apices, developing shoot buds, young fruits. Mostly cytokinin found in regions where rapid cell division takes place.

Complete answer:Option A: Cytokinin induces cell division in young fruits and it is used to increase the self-life of cut fruits but for improving the quality of fruits the ethylene hormone is important. Ethylene is also known as a ripening agent because it is involved in the ripening of fruits. Ethylene is a gaseous plant hormone.
Hence improving the fruit quality is not a function of cytokinin.
Option B: Apical dominance is the phenomenon by which the presence of apical bud does not allow the nearby lateral buds to grow. In the presence of cytokinins in later buds the supply of water and minerals increases to lateral buds. Therefore lateral buds grow even in the presence of apical buds. So cytokinin overcomes apical dominance. Auxin is the hormone that promotes apical dominance or inhibits the growth of lateral buds.
Option C: The concentration of abscisic acid increase during drought condition that helps in the closing of stomata to prevent the loss of water during transpiration. So cytokinin Is not control and closing the stomata.
Option D: Cytokinin is important for cytokinesis (a division of the cytoplasm) which is an important step in cell division. So the main function of cytokinin is to stimulate cell division.
So the option (D) is correct option.

Additional Information:
The other function of cytokinin is:
1.Overcome apical dominance
2.Delay in senescence
3.Help in the growth of leaves and shoot

Note: The first natural cytokinin was isolated from unripe maize grains. Cytokinin is derivative of purines. Cytokinin and auxin both hormones are responsible for cell division in a mass of undifferentiated cells.