Abstract:

With the increasing shortage of urban water resources, the problem of drought is becoming more and more serious. To study the drought resistance of different greening tree species can provide a theoretical basis for their cultivation and application under different site conditions, and is of great significance to landscaping. Two-year-old seedlings were used as test materials. After a certain period of drought stress treatment, 15 growth physiological indicators, such as biomass, net photosynthetic rate, and malondialdehyde and etc., were measured. The drought resistance of 9 greening tree species was evaluated by comprehensive drought resistance coefficient evaluation, membership function method and cluster analysis. The results showed that drought stress had significant effects on the growth, physiological and biochemical characteristics of the 9 greening tree species. Water deficit could lead to the inhibition on the seedling growth, and the significant increase in the activity of antioxidant enzymes and the content of osmotic regulators (P<0.05). The evaluation results obtained by the three comprehensive methods were basically the same. Based on the results, the 9 tree species could be divided into two groups: one was drought-resistant tree species including Euonymus japonicus and Eucommia ulmoides, while the other one included weak drought-resistant tree species like Ligustrum lucidum, Hibiscus syriacus and Magnolia wufengensis, and drought-sensitive tree species such as Magnolia denudata, Koelreuteria paniculata, Forsythia suspensa and Catalpa bungei. The drought resistance of the 9 greening tree species followed the order of Euonymus japonicus > Eucommia ulmoides > Ligustrum lucidum > Hibiscus syriacus > Magnolia wufengensis > Magnolia denudata > Koelreuteria paniculata > Forsythia suspensa > Catalpa bungei.

Key words: greening tree species, drought resistance, comprehensive evaluation, membership function method, principal component analysis, cluster analysis