关键词: 小叶杨, 杂交杨, 生理状况, 科尔沁沙地

Abstract: The seasonal change characters of stomatal conduction and state of water in two variety poplar trees were studied by Ap4 parometer and Pressure Volume technique. The results show: ① Stomatal conduction of Populus simonii was much higher than Populus spp. in dry May and June, they were 320.6 μmol·m^-2·s^-1, 283.0 μmol·m^-2·s^-1 and 46.5 μmol·m^-2·s^-1, 12.6 μmol·m^-2·s^-1 respectively. The state of affairs reversed in humid July, the data were 456.7 μmol·m^-2·s^-1 for P. simonii and 604.5 μmol·m^-2·s^-1 for Populus spp.. In the end of growth season (end of August), the values of stomatal conduction of two variety poplar trees ware almost the same. ② The osmoregulational ability and drought resistant ability of tender leaves of two trees have little difference. Then the ability of Populus spp. was a little higher than P. simonii with growing and there was a significant differance in June. The abilities of osmoregulational and drought resistance of two poplar trees were tending to increase with leaves and twigs getting older.

Key words: Populus simonii, Populus spp., Physiological state, Horqin sandy land