Biochemical and physiological responses of bulblets of Lycoris aurea to exogenously applied N-(2-chloro-4-pyridyl)-N1-phenylurea

SummaryOne-year-old bulblets of Lycoris aurea were obtained by propagation of cuttings. Different concentrations of N-(2-chloro-4-pyridyl)-N1-phenylurea (CPPU; 0, 1.0, 2.0, 5.0, 7.5, or 10.0 mg l 1) were sprayed on all the leaves on each plant at the green-leaf stage. Morphological indices including bulblet fresh weights (FW) and diameters, carbohydrate concentrations, the activities of enzymes related to starch metabolism, and the concentrations of endogenous hormones were determined in bulblets during dormancy. Bivariate correlation analysis was used to analyse the relationships of all parameters. The results showed that spray treatment with an appropriate concentration of CPPU was beneficial for the enlargement of L. aurea bulblets. The optimum concentration was 1.0 mg l 1. Bivariate correlation analysis showed that bulblet FW and diameter had a significant (P ≤ 0.05) positive correlation with starch concentration. The concentration of zeatin riboside (ZR) showed a significant (P ≤ 0.01) positive corre...