影响新疆阜康荒漠地区红砂光合日变化因素的分析

目的 研究新疆阜康荒漠区域优势植物红砂（Reaumuria soongorica）光合及其影响因子的日变化，分析蒸腾速率、光合有效辐射、空气温度、气孔导度、相对湿度、叶面温度、胞间CO2浓度和空气CO：浓度对光合速率的影响。方法利用CI-301 CO2气体分析仪，测定光合及其影响因子的日变化，并进行相关性和多重线性回归分析。结果光合速率日变化形成典型的双峰型；蒸腾速率的日变化曲线呈双峰型；光合有效辐射、空气温度日变化和叶面温度的日变化曲线相近，在午后均呈逐步降低趋势；气孔导度与生境相对湿度的日变化为先下降，然后保持在一定的水平上；水分利用率全天递减。空气CO2浓度、空气温度、相对湿度及叶面温度和气孔导度对红砂光合速率具有显著的影响。结论红砂光合速率日变化曲线形成典型的双峰型，温度是影响红砂光合特性的重要因子之一，气孔因素则是导致其光合速率下降的决定因素。

Major factors on diurnal changes of photosynthetic rate of Reaumuria soongorica in Fukang desert, Xinjiang

Aim To study the diurnal change of photosynthetic rate of Reaumuria soongorica, a dominant species in Fukang desert, Xinjiang, and its major influencing factors including the transpiration rate, photosynthetic active radiation, air temperature, stomatal conductivity, relative humidity, leaf temperature, intercellular CO2 concentration and CO2 concentration in atmosphere. Methods Measure the diurnal changes of photosynthetic rate and its major influencing factors by using CI-301 CO2 GAS ANALYZER and carry, out correlation and regression analysis. Results Both the diurnal changes of photosynthetic rate and transpiration rate show typical bimodal curves ; the curves of the diurnal changes of photosynthetic active radiation, air temperature and leaf temperature are similar and all show a downtrend in the afternoon ; those of stomatal conductivity and relative humidity both remain on a certain level after a downtrend ; that of water utilization rate shows a downtrend all through the day. Conclusion CO2 concentration in the atmosphere, air temperature, relative humidity, leaf temperature and stomatal conductivity exert obvious effects on the photosynthetic characteristic of Reaumuria soongorica. Among these factors, temperature is considered important and stomatal conductivity is the determinative factor in the decline of photosynthetic rate.