Abstract: In order to investigate the photosynthetic characteristics and physiological changes of invasive plant Cenchrus pauciflorus under heterogeneous nutrient and drought and rehydration conditions,this study took Cenchrus pauciflorus as the test object,and set four nutrient levels including CK,low nutrient,medium nutrient and high nutrient. On the basis of fertilization,two kinds of water treatments (post-drought watering and normal watering) were set up,and after 40-day cultivation,three cycles of drought rehydration experiment (each cycle was 7 days) were started. The results showed as follows:In cycle Ⅰ,the Transpiration rate (Tr) of nutrients in the drought group reached the maximum of 2.950 mmol·m^-2·s^-1; After each rehydration,stomatal conductance (Gs),intercellular carbon dioxide concentration (Ci) and Tr all showed significant recovery. Instantaneous water use efficiency (WUE) increased significantly in the 3rd drought rehydration cycle. Superoxide dismutase (SOD) activity reached the maximum value of 384.17 U·g^-1FW in the high-nutrient drought group. Comprehensive analysis showed that Cenchrus pauciflorus had stronger resistance to water stress at the medium nutrient level,and still had stronger drought adaptation ability,higher water use efficiency and water recovery ability after drought rehydration.

Key words: Cenchrus pauciflorus, Net photosynthetic rate, Water use efficiency, Drought rehydration

摘要： 为探究入侵植物少花蒺藜草(Cenchrus pauciflorus)在异质养分及干旱复水条件下的光合特性及生理变化，本研究以少花蒺藜草为试验对象，设置对照(CK)、低养分、中养分和高养分4个养分水平，在施肥的基础上设置2种水分处理(干旱后浇水与正常浇水)，培育40 d后，开始3个周期的干旱复水试验(每个周期为7 d)。结果表明：在周期Ⅰ时，干旱组中养分的蒸腾速率(Transpiration rate,Tr)达到最大值2.950 mmol·m^-2·s^-1；在每次复水后，气孔导度(Stomatal conductance,Gs)，胞间CO₂浓度(Intercellular carbon dioxide concentration,Ci)，Tr都有明显的回升，瞬时水分利用效率(Instantaneous water use efficiency,WUE)在第3次干旱复水周期时，水平明显提高；少花蒺藜草高养分干旱组超氧化物歧化酶(Superoxide dismutase,SOD)活性达到最大值384.17 U·g^-1FW。综合分析，在中养分水平，少花蒺藜草对水分胁迫的抗性更强，经历干旱复水后仍具有较强的干旱适应能力、较高的水分利用效率和复水恢复能力。

关键词: 少花蒺藜草, 净光合速率, 瞬时水分利用率, 干旱复水