江苏地区凤眼莲叶片光合作用对光照度和温度的响应

Response of Photosynthesis of Leaves to Light and Temperature in Eichhornia crassipes in Jiangsu Province

为太湖地区凤眼莲高产栽培技术提供技术支持,以江苏地区人工围养生长的凤眼莲群落为研究对象,在8月份其旺盛生长季节,采用LI-6400光合作用测定系统,以开放式气路测定了其不同叶位的净光合速率,以及功能叶片在不同光照度和温度时的光合曲线。结果发现,倒3~倒6叶都是成熟的光合功能叶片,其中倒4叶的最大光合速率（Pmax）、光补偿点（LCP）和表观量子效率（AQE）分别为（34.50±0.72）μmol/（m^2·s）、（20.25±3.6）μmol/（m^2·s）和0.053 2±0.001 4,均显著高于水稻和玉米;凤眼莲光饱和点为（2 458±69）μmol/（m^2·s）,也明显高于水稻,与玉米接近。认为江苏地区光合有效辐射和大气温度是限制凤眼莲生物量的重要环境因子。

Photosynthetic characteristics of Eichhornia crassipes with artificial culture were monitored using LI-6400 portable photosynthesis system in Jiangsu Province in August,2009.Net photosynthetic rate（Pn） in the leaves at different positions and Pn′s response to light and temperature in the fourth leaf from top were measured in an open-circuit gas channel system.The third to sixth leaves from top were all mature leaves with high Pn.The values of the maximum net photosynthesis（Pmax）,light component point（LCP） and apparent quantum efficiency（AQE） of the fourth leaf from top leaves in Eichhornia crassipes were（34.50±0.72）μmol/（m^2·s,（20.25±3.60）μmol/（m^2·s and 0.053 2±0.001 4,respectively,which were both higher significantly than those in rice and maize.Moreover,light-saturation point of the leaves in Eichhornia crassipes was 2 458±69μmol/（m^2·s,which was significantly higher than that in rice and close to that in maize.It came to a conclusion that air temperature and photosynthetic active radiation（PAR） in Jiangsu Province are important environmental factors restricting dry matter accumulation in Eichhornia crassipes.