Abstract: Water stress of Microula sikkimensis was studied.The results showed that the soil watercontent for microula sikkimensis existing and producing were 11.22% and 40.41 %, meanwhile soil effec-tive water were 7% and 36%, leave water content were 83.4%and 88.70%, water deficit were 59.64%and 48.92%, respectively.Water stress of Microula sikkimensis were brought about soil drought, so its cellmembrane would be injured.When the cell membrane injured rate was as high as 50%, plant survivingrate was only 42%, when it was reaching 65%, the all plant would be died.The regularity about water po-tential and transpiration intensity and photosynthesis intensity were also studied in this paper.The criticalpoint of water deficit in Microula sikkimensis could be judged by soil water content, water deficit in plant,plant water potential and cell membrane permeability.

Key words: Microula sikkimensis, Water deficit, Transpiration intensity, Photosynthesis rate, Water stress

摘要： 微孔革对水分胁迫反应的研究结果表明,微孔草生存和生长所需土壤含水量分别为11.22%和40.41%,土壤有效水为7%和36%,叶片含水量为83.40%和88.70%,水分馆和亏缺为59.64%和48.92%。当土壤持续干旱,微孔草受到干旱胁迫时,细胞膜遭到破坏,质液外渗,电导率增高,当细胞伤害率达50%,其成活率仅42%,细胞伤害率达65%,植株则全部死亡。同时提出水分胁迫下的水势、蒸腾和光合强度的变化规律,提出以土壤含水量、植物水分饱和亏缺、植物水势和细胞膜透性判断微孔草缺水的临界值。

关键词: 微孔草, 水分饱和亏缺, 蒸腾强度, 光合速率, 水分胁迫