Abstract:

Growth and physiological mechanism for ornamental crabapple in re-sponses of to soil drought stress and re-watering was investigated, and some growth and physiological parameters for evaluating drought resistance were selected. Changes in leaf relative water content(RWC), water weight loss(WWL), ratio of shoot growth(SGR), special leaf dry weight (SDW), net photosynthesis(P_n), transpiration(T_r), stomatal conductivity(C_s), water use efficiency(WUE), relative electric conductivity (REC), proline content(PRO), soluble protein content(SPC) and drought injury index(DI) of 13 ornamental crabapple cultivars were examined under soil drought stress by withdrawing water and then re-watering in potting plants. Drought resistance of ornamental crabapple cultivars was evaluated synthetically by cluster analysis. The results indicated that soil drought stress reduced significantly RWC, SGR, WWL, P_</em>n, T_r and C_s, increased significantly DI, WUE and REC, but had no consistent effects on SDW, PRO and SPC in ornamental crabapple cultivars. Drought resistance of ornamental crabapple cultivars were divided into 4 classifications by cluster analysis. 'Belgian Erect’ and 'Royalty’ were the strongest drought-resistant, followed by 'Belgian Weep’,'Kelsey’ and 'Sparkler’, and then by, 'Radiant’ and 'Snowdrift’, while 'Red Splendor’, 'Red Jade’ and 'Indian Magic’ belonged to the lowest drought-resistance. It proved that there was a significant differences in resistance to the soil drought stress among the ornamental crabapple cultivars.

Key words: ornamental crabapple, soil drought stress, rewatering, growth and physiological characteristics, drought resistant evaluation