Cytokinin Activity During Development of Cotton Fruit.

Cytokinins in cotton fruits were detected by the soybean callus bioassay on the 1st day after anthesis. Peak cytokinin activity occurred from the 4th to the 9th day and then declined to little or none by the 18th day after anthesis. The principal cytokinin remained below R_f 0.2, when chromatographed on paper with water-saturated sec-butanol, and predominated throughout the period of cytokinin activity. Another cytokinin, migrating to R_f 0.8, remained less active. [ABSTRACT FROM AUTHOR]