A Sensitive Bioassay for Gibberellins based on Retardation of Leaf Senescence in Rumex obtusifolius (L.)

Abstract

THE senescence and yellowing of detached leaves and leaf disks of many plants are retarded by low concentrations of kinetin. Gibberellic acid (GA) and indolyl-3-acetic acid (IAA) may also induce a similar response, depending on the age of the leaf and the species. Thus, mature leaves of dandelion (Taraxacum officinale) respond to low concentrations of kinetin and GA, but scarcely at all to IAA; whereas in banana (Musa cavendishii Lamb.) all three types of hormone are effective in retarding leaf senescence. Leaves of the broad-leaved dock (Rumex obtusifolius) are unusual in responding only to gibberellin, and this has been made the basis of the bioassay technique described in this report.