Abstrakt: |
Hibiscus rosa-sinensis ‘Jane Cowl’ in 1.5–1 pots were given a soil drench of 0.2 mg uniconazole, pruned 2 weeks later, and treated with a foliar application of GA4+7 at 0, 25 (once or four times every 2 weeks), 50 (once or twice every 4 weeks), or 100 mg L-1. One application of GA4+7 at 100 mg L-1, two applications at 50 mg L-1, and four applications at 25 mg L-1 were more active in partially restoring stem elongation and caused nearly normal leaf production than other GA treatments, but promoted the abscission of the lower leaves. The size of the individual leaves, but not stem diameter, increased following GA4+7 application. Multiple applications of GA4+7 stimulated flowering of the retarded plants. Uniconazole resulted in short pedicels bearing short cells with increased diameter, as well as larger pith, vascular, and cortical tissues than the untreated control. Four applications of 25 mg L-1 GA4+7 to uniconazole-treated plants resulted in long pedicels, having long cells similar to the control. Results of the histological study suggest that uniconazole either slowed cell division or caused cell division to cease early. |