Abstract:

In order to compare the drought resistance capabilities among tree species, 7 physiological indexes were measured and studied by treating water stress of potted seedlings of three tree species in Beijing region. The results showed that with the increase of drought stress, leaves water contents, relative water contents, chlorophyll contents and photosynthetic rate decreased obviously, leaves soluble sugar contents, leaves proline contents and leaves relative conductivity increased. Many potted seedlings dead when the soil water contents were lower than 4%. After 20d drought treatment, leaves water contents of Amorpha fruticosa, Rhus typhina and Vitex negundo decreased 18.85%,15.52% and 12.28%, relative water contents decreased 42.06%,29.63% and 16.42%, chlorophyll contents decreased 59.17%,63.29% and 45.67%,the photosynthetic rate of Vitex negundo was smallest influenced，Amorpha fruticosa was largest influenced, leaves soluble sugar contents increased 85.80%,25.29% and 34.56%, leaves proline contents increased to 7.34 times,4.29 times and 5.02 times of 0d numerus, leaves relative conductivity increased 38.69%,14.17% and 25.93%. Compare the physiological indexes that had high correlation with soil water contents, the drought resistance capabilities of Vitex negundo were greater, and then were Rhus typhina and Amorpha fruticosa.