Influence of CuSO4 spectral filters, daminozide, and exogenous gibberellic acid on growth ofDendranthema Xgrandiflorum (Ramat.) Kitamura ‘bright golden anne’

Abstract

The response of chrysanthemum plants to gibberellic acid (GA3) and daminozide, grown under 6% CuSO4 and water (control) spectral filters, was evaluated to determine the involvement of gibberellins in regulation of plant height under CuSO4 filters. The CuSO4 filter increased the red (R)/farred (FR), and blue (B)/R ratio (R=600–700 nm; FR =700–800 nm; B=400–500 nm) of transmitted light. PPF under 6% CuSO4 filter was reduced by about 34% compared to PPF under water filter which averaged about 750 μM·m−2·s−1. Control plants were shaded with Saran Wrap to ensure equal PPF as in the CuSO4 chamber. GA3 application increased plant height under both the control and CuSO4 filter, but the height increase under the CuSO4 filter was about 20% greater than that under the control filter. Daminozide treatment reduced plant height under the control and CuSO4 filter, but the height reduction in control plants was slightly greater than under the CuSO4 filter. The height reduction caused by daminozide was prevented by GA3 application in plants grown under the control or CuSO4 filter. The results suggest that GA3 may be partially involved in height reduction under CuSO4 filters.