棉花和芦苇光合特性、环境适应策略及固碳效应比较研究

Comparative Study on Photosynthetic Physiological Characteristics,Environmental Adaptation Strategies,Effect of Carbon Sequestration of Gossypium and Phragmites communis

【目的】通过对艾比湖流域典型棉花和芦苇群落光合生理指标进行测定,比较二者的光合特性、光合适应策略及CO2固定,为深入分析干旱环境对植物个体尺度的生理生态过程的影响提供参考。【方法】利用Li-6400便携式光合测定系统测定农田作物棉花和非农田植物芦苇光合特性,通过非直角双曲线模型拟合光响应曲线;采用主成分法和通径分析法解释生理生态因子对光合速率的影响,揭示两种典型植物的光合特性差异及其适应干旱环境的策略。【结果】光响应曲线在光强为1 600μmols/(m2·s)时,棉花的最大光合速率是26.8μmolCO2/(m2·s),芦苇的最大光合速率30.0μmolCO2/(m2·s)。棉花、芦苇光合特性变量中叶片温度(P=0.952)差异极不显著,水分利用效率(P=0.630)无显著差异,光合速率(P=0.005)、气孔导度(P=0.000 3)和蒸腾速率(P=0.019)存在显著性差异。综合主成分分析和通径分析表明生态因子中空气湿度是两种植物最主要的限制因子;生理因子中,棉花的最主要决策因子为蒸腾速率;芦苇的最主要决策因子为气孔导度。【结论】(1)两种植物光合速率、气孔导度、蒸腾速率存在极显著差异;(2)限制两种植物光合速率的主要生态因子均为空气相对湿度;(3)影响棉花的为蒸腾速率,限制因子为叶片温度,芦苇的则为气孔导度,限制因子为蒸腾速率;(4)水分利用策略棉花为保守型,芦苇为挥霍型;(5)棉花具有很好的固碳能力,但随季节和土壤环境的改变而降低;而芦苇保持一定的固碳能力随季节变化不明显。

[ Objective] This project aims to measure the photosynthetic physiological indexes of Gossypium and Phragmites communis in Ebinur Lake basin, then compare the characteristics of them, and analyze the influence of the physiological and ecological processes on arid area at plant individual scale, and further probe into the status and contributions in those two plant communities in seasonal changes of ecosystem CO2 source/ sink in arid area. [ Method ] The Li -6400 portable photosynthesis system was used to measure photosynthetic characteristics and environmental factors of Gossypium and Phragmites communis, and non - rectangular hyperbolic model was applied were adopted to account reveal the differences in to fit light response curve. Principal component analysis and path analysis methods for the effects of physiological and ecological factors on photosynthetic rate and then photosynthetic characteristics of two plants and strategies adapted to arid environment. [ Result]The maximum photosynthetic rate of Gossypium and Phragmites communis were 26.8 i^molCO2/（ m2 ~ s） and 30 ixmolCO2/（m2 ~ s）, respectively, when the light intensity amounted to 1 600 Ixmol/（ms ~ s）, for the photosynthetic characteristics variables of Gossypium and Phragmites communis, there was no extremely significant difference in leaf temperature （ P = 0. 952） and water use efficiency （ P = 0. 630）, and there was significant difference in photosynthetic rate（ P =0. 005 ） ,stomatal conductance（ P =0.000 3）and transpiration rate（P =0.019）. Colligating the principal component analysis and path analysis, which showed that the air humidity was the main limiting factor of the two kinds of plants, and the main decision factor of C, ossypium and Phragmites communis were transpiration rate and stomatal conductance, respectively. [ Conclusion ] The results showed that： （1）There was extremely significant difference in photosynthetic rate, stomatal conductance and transpiration rate for the two plants; （2） Air relative humidity was the limiting factors of the two plants photo- synthetic rate;（3 ）Transpiration rate affected photosynthetic rate of Gossypium, and the limiting factor was the leaf temperature. Stomata conductance affected photosynthetic rate of Phragmites, and the transpiration rate was the limiting factor; （4） Gossypium was conservative water use strategy and Phragmites was spender water use strategy ; （5） Gossypium had good carbon sequestration ability, but it varied with seasons and soil environ- merits while Phragmites did not show obvious variation with the changing seasons.