Effect of Chlormequat on Cold-resistance of Phoebe microphylla

  Objective  Effect of chlormequat application on low-temperature tolerance of Phoebe microphylla was studied.

  Method  Under simulated conditions, seedlings of P. microphylla were subjected to low-temperature stress with treatments of chlormequat chloride (CCC) in different concentrations. The contents of soluble protein (SP) and malondialdehyde (MDA), as well as the relative electrical conductivity (REC) and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of the seedlings were determined.

  Result  After spraying with CCC solutions, SP in leaves increased and reached a maximum when 50 mg/L of CCC was applied; MDA reduced when 100 mg·L^-1 of CCC was applied at 0℃ or -2.5℃; REC declined at the presence of 50 mg·L^-1 of CCC; and, the activities of SOD, POD and CAT peaked at the spraying of 100 mg·L^-1 of CCC at -2.5℃.

  Conclusion  Based on the above mentioned cold resistance indicators, the CCC application on the seedlings at 100 mg·L^-1 scored the highest among all tested treatments on the membership function evaluation. It was considered effective for improving the cold resistance of P. microphylla.