Question

Write any four psychological effects of cytokinins in plants.

Answer 1

Plant hormones are chemical signals which are produced in the plants and occur in low concentration. They control the growth and development of plants. Plant hormones regulate metabolism, germination, and other physiological activities. They are produced in the stem, buds, and tips of the roots.

Complete step by step answer:
Cytokinin is a plant hormone that promotes plant growth cell division or cytokinesis in plants. Cytokinins regulate shoot meristem size and the growth of leaves and shoots. Cytokinins intervene in axillary bud release from apical dominance.
Psychological effects of cytokinins are:
Cell division: Cytokinins induce cell division and help in the continuance of cell division. Cytokinins induce root development and the development of buds and shoots. Cytokinins help with the expansion of cells in leaf and cotyledons.
Senescence: Cytokinins delete the process of senescence of leaves and other organs. They resist the extreme conditions of temperature and disease.
Cell enlargement: When the leaf discs cut themselves from etiolated leaves sell enlargement takes place.
Initiation of fascicular cambium: Cytokinin helps in inducing interfascicular cambium. It is seen in pea stem sections.
Cytokinins help with the mobilization of plants. Cytokinins help in promoting lateral bud development in dicots when the non-growing lateral bud is dominated by the shoot apex. Cytokinins can cause morphogenetic changes in undifferentiated callus. Cytokinins help in the counteraction of apical dominance. They promote the development of chloroplast. Cytokinins help in the conversion of etioplast into chloroplast when the etiolated seedlings are exposed to light after the treatment with cytokinins. It helps in promoting germination and breaks the dormancy of seeds. They are derived from adenine and are synthesized in the roots. The yellowing of leaves is the result of senescence occurring as the proteins are broken down and chlorophyll is destroyed. Cytokinins prevent senescence by stabilizing the protein content and chlorophyll in the leaves and structure of chloroplasts.

Note: Cytokinins discovered by scientist F Skoog, C.Miller, and their coworkers during the late 1950s. The first cytokinin discovered was adrenaline which was a derivative of kinetin i.e. 6-furfuryl-aminopurine. Zeatin was the first natural cytokinin which was isolated from corn in the late 1960s. It was found in coconut milk. They help in the plant tissue culture and are purified form from many suppliers and are available commercially.