sitokiniini

Sitokiniini is a class of plant hormones that play a crucial role in plant growth and development. They are a type of phytohormone, meaning they are produced by plants. The term "cytokinin" itself derives from the Greek word "kytos" meaning cell, and "kinein" meaning to move, reflecting their primary function in promoting cell division.

Cytokinins were first discovered in the mid-20th century during research aimed at understanding plant tissue culture. Their synthesis primarily occurs in the root tips and young fruits of plants. From these sites of production, they are transported throughout the plant, influencing various developmental processes.

The main functions of cytokinins include stimulating cell division (cytokinesis), which is essential for growth and repair. They also play a significant role in cell enlargement, differentiation, and the prevention of senescence, the aging process in plant tissues. Cytokinins work in conjunction with other plant hormones, most notably auxins, to regulate these processes in a coordinated manner. The ratio of auxins to cytokinins is particularly important in determining the developmental fate of plant cells, such as whether they will form roots or shoots in tissue culture.

Beyond these fundamental roles, cytokinins influence a variety of other plant responses. They can affect bud formation, delay leaf aging, promote the development of chloroplasts, and contribute to fruit development. Their application in agriculture and horticulture can be beneficial for improving crop yield and quality by influencing flowering, fruit set, and overall plant vigor.