ANTAGONISTIC EFFECTS OF UNICONAZOLE AND GA4+7 ON SHOOT ELONGATION AND FLOWER DEVELOPMENT IN NELLIE WHITE EASTER LILY

Uniconazole soil drench treatments (0.1-0.3 mg plant-1) reduced final plant height by 20-50%. Uniconazole foliar spray treatments (0.1-2 x 0.2 mg plant-1) was more effective than soil drench and reduced final plant height by 49-70%. Shoot dry weight was also significantly reduced by uniconazole treatments. The time to flower was unaffected by soil drench treatments but it was delayed by the spray treatments. Two-spray applications of uniconazole at 0.2 mg plant-1 reduced up to 30% whole plant net photosynthesis on a leaf area basis and 66% on a per plant basis compared with the control plants. The reduction in shoot dry weight by uniconazole is suggested to be due to lower whole plant net photosynthesis. GA4+7 spray at 200 mg l-1 counteracted the inhibiting effect of uniconazole on shoot growth and the rate of flower bud development.