Physiological Response and Comprehensive Evaluated on 3 Species of Landscape Tree Seedlings Subjected to Soil Drought and Waterlogging

This paper disposed of Cinnamomum burmannii, Elaeocarpus sylvestris and Ilex rotunda seedlings in drought, waterlogging and drought-waterlogging soil conditions, 8 physiological indexes of each species were determined. Based on the fuzzy membership function, water stress resistance and physiological response of the 3 species of landscape tree seedlings was explored. The results showed that in waterlogging treatment, the malondialdehyde increment of I. rotunda decreased and its superoxide dismutase actiity reduced slightly, with mild waterlogging injury. In drought treatment, malondialdehyde of E. sylvestris and I. rotunda increased, superoxide dismutase activity and water use efficiency decreased significantly, these indicated E. sylvestris and I. rotunda had more serious damage by drought, whereas the malondialdehyde and superoxide dismutase activity of C. burmannii decreased slightly, showed that C. burmannii had the slightest injury degree. In drought-waterlogging treatment, the soluble protein content of 3 seedlings increased while superoxide dismutase activity, stomatal conductance and transpiration rate decreased significantly. These 3 seedlings could enhance osmotic adjustment ability by increasing soluble protein content so as to cope with water stress. In continuous drought and flood-drought treatment, seedlings reduced transpiration by closing the stomata to maintained higher water use efficiency.