CHANGES IN ABSCISSION-ACCELERATING SUBSTANCES WITH DEVELOPMENT OF COTTON FRUIT

Authors

  • O. E. SMITH

    1. Crops Research Division, ARS, U.S. Department of Agriculture, Davis, California
    Search for more papers by this author
    • *

      Department of Vegetable Crops, University of California, Riverside.


Summary

Cotton bolls of known ages from 2 to 50 days after anthesis were extracted with acetone. The chromatographed extracts were examined for abscission activity on the cotton explant test and gibberellin activity on the dwarf maize test. The abscission-accelerating substances (ABA and gibberellins) were very high in young fruit, showing a peak at about 6 days, then declined to nil at 20 days. An unidentified abscission accelerator showed a marked peak at 15 days. Abscisic acid, GA3, another gibberellin which acts biologically like GA5 and GA9, and an abscission-retarding substance were all extracted from 5-day-old bolls.

Ancillary