大气CO_2浓度升高对棉花叶绿素和光合指标的影响

Effects of CO_2 Enrichment on Cotton Chlorophyll and Photosynthetic Indicators

【目的】研究大气CO2浓度升高和不同施氮量下棉花叶片叶绿素CCI值、净光合速率、蒸腾速率和水分利用率的变化情况。【方法】设置不同CO2浓度和施氮量的田间小区,供试棉花品种为新陆早33号,共12个试验小区。【结果】(1)随大气CO2浓度的增加,适宜施氮(N2)处理,棉花叶片叶绿素CCI值呈增高趋势,差异显著;C720处理在通气结束后出现叶片早衰。(2)随着CO2浓度升高,相同施氮水平下,棉花净光合速率随通气时间增加表现为前期上升但后期下降,超量施氮可以缓解这一现象。(3)随着CO2浓度增加,不同施氮处理均表现为棉花蒸腾速率前期下降但中后期升高的趋势。(4)棉花叶片水分利用率随CO2浓度增加呈现出前期增加后期下降的趋势。【结论】在新疆绿洲棉田,新陆早33号品种的叶绿素和光合指标在C540-N2处理表现出较好适应性,有利于延缓棉花早衰。

[ Objective ] CO2 concentration exaltation causes a series of environmental issues, vegetation can give react to environmental changes by adjusting photosynthesis and transpiration through stoma. Through a plot experiment, the project studied the cotton leaves＇chlorophyll CCI value, net photosynthetic rate, tran- spiration rate, water use efficiency difference under different CO2 concentrations and nitrogen levels. [ nethod]A total of experimental plots of different CO2 concentrations and nitrogen levels in the field were set up. [ Result ] Data showed that： （ 1 ） Under appropriate nitrogen level （ N2 ）, the cotton leafg chlorophyll CCI value rose with CO： concentration increasing, with significant difference. Under No, N1 and N3 level, CCI value rose with CO2 concentration increasing at the ending period. Premature aging appeared after C720 treatment. （2） Under the same nitrogen level, cotton leaf＇s net photosynthetic rate rose at the beginning period, but with time going on, it decreased at the ending period, excessive nitrogen fertilization alleviated this phenomenon.（3）With CO2 concentration increasing, transpiration rate decreased at the beginning period but increased at the middle and the ending period under different nitrogen levels. （4）With CO2 concentration increasing, cotton leaf＇s water use efficiency increased at the beginning period, but with time going on, it decreased gradually. [ Conclusion] In Xinjiang Oasis cotton farm land, C540 -N2 treatment on Gossypiurn hirsutum L. 33 chlorophyll and photosynthetic indicators is closely related to cotton premature aging. The result of good adaptability shown in C540 -N2 treatment showed that it could make contribution to deferring cotton premature aging.