Cytokinin (6-BA), plant growth regulators
Cytokinin, one of the current five hormones, is a kind of plant hormones which can promote the division and differentiation of cell. There are 10 kinds of known endogenous cytokinin (CTK short or CK) in higher plants, of which zeatin is the most active. Currently, there are many industrial synthetic products, among which commonly used in production are 6 benzylaminopurine (6 BA) and kinetin (KT, KN dynamic fine).
The pure product of 6-benzylaminopurine is needle-like crystals, insoluble in water, but soluble in alkaline or acidic solution; the pure product of kinetin (KT, KN, dynamic precision) is the white solid, insoluble in water, soluble in alkaline and acid solution.
The main physiological function of 6-benzylaminopurine is to promote cell division and induce cell differentiation. It is commonly used in tissue culture, but also for improving the percentage of fruit setting, promote the growth of fresh vegetables and fruits and so on. On jujube, its main function is to promote the fruit setting during the flowering period, and promote rapid growth and development of young fruit, etc. It is generally used at a concentration of 10 mg/l, sometimes mixed with GA, and promoted fruit and so on. Cytokinin can promote cell division and enlargement, promote flowering of short-day plant, and even can promote flowering of long-day plant. It can also promote bud germination, breaking apical dominance, and can delay aging and prolong the flowering period. Cytokinin compounds commonly used in the production are more than 10 kinds, such as kinetin, cytokinin, azakinetin and so on. On vegetables, it is mainly use 6-benzyl adenine (6BA), and the main role is to promote the expansion of melons, fruits and vegetables. Cytokinin can be directly absorbed through the roots, stems, leaves, which can stimulate cell division and promote the formation of chlorophyll, photosynthetic and improve flowering fruit-setting rate, enhancing crop disease resistance. So as to achieve the purpose of increasing production, value added, in particular to increase output of early and medium stage.
The use of concentration of cytokinin is about 500-600 times, generally for foliar application. Tomatoes, eggplant, peppers and cucumbers need to start spraying one week after planting and seedlings. Spray every 7-10 days time, continuous spray 3 to 4 times (can be mixed with spraying insecticides, fungicides, etc.). The best of spraying time is before 9 o’clock in the sunny morning, and after 3 o’clock in the afternoon, if rain falls within 2 hours after spraying, should fill the spray.
According to the analysis, cytokinin has a significantly role in increase production and added value on tomato, eggplant, peppers and cucumbers, an increase production margin of 11.2% -24.3 %, and value-added margin of 15.3% -25.6 %. Thus, it is worth to widely application on the vegetables. As early as 1957, Miller and Skoog proposed the cytokinin/Auxin regulation of plant organ formation theories. They point out that, the ratio of a high concentration of cytokinin and a low concentration of auxin is beneficial to differentiation and formation of the stems, and the ratio of a low concentration of cytokinin and a high concentration of auxin is beneficial to differentiation and formation of adventitious roots. Currently, most absolutely rooting medium stage, generally are removed the cytokinin, while only adding an appropriate amount of growth hormone to promote rooting.