Relationship between the Greening of Leaves by the Treatment with a Gibberellin-biosynthesis Inhibitor and Leaf Area or Nitrogen Content in Cucumis sativus L.

Abstract

The relationship between the greening of leaves by the treatment with a gibberellin-biosynthesis inhibitor, uniconazole-P (U), and leaf area, and leaf mineral (N, Mg and Fe) contents in Cucumis sativus L. was examined. U induced greening of leaves and the reduction of leaf area but not in all cases. Thus, the greening was not always accompanied by the reduction in leaf area. The treated leaves were restored to their natural green color after the treatment with U was discontinued. Total nitrogen content of leaves was proportional to the degree of green coloration, but Mg and Fe contents were not. According to the previous reports, U enhances the level of endogenous cytokinins which increases the chlorophyll content of leaves. Thus, the leaves treated with U may be responding to cytokinins rather than to the inhibition of gibberellin biosynthesis.