Effects of Prohexadione Calcium on growth and gibberellins contents of Chrysanthemum morifolium R. cv Monalisa White

The effect of Prohexadione Calcium (Pro-Ca) and daminozide was observed on the growth characteristics and endogenous gibberellin contents of Chrysanthemum morifolium R. cv Monalisa White. Three concentrations viz. 100, 200 and 400 ppm of Pro-Ca and a single concentration of daminozide (800 ppm) were applied three times with 7 days interval on three weeks old plant under greenhouse condition. Pro-Ca suppressed the plant length up to 30.7% while daminozide inhibited up to 27.12% at optimum concentration. The chlorophyll contents and stem diameter were higher than control, while the fresh weight and flower number insignificantly reduced with such treatments. Gibberellin (GA) analysis showed that Pro-Ca and daminozide application significantly lowered bioactive GA(1) content, although the amount of its immediate precursor GA(20) was fractionally higher. Bioactive GA(4) content was slightly higher than the control while significant difference in GA(9) was found between the plants treated with Pro-Ca and daminozide. Current study showed that both early C13 hydroxylation and non-C13 hydroxylation pathways of GA biosynthesis are operational in C. molifolium. (C) 2009 Elsevier B.V. All rights reserved.