祁连山白桦群落光合速率及其对环境因子的响应研究

Net Photosynthetic Rate of Betula Pllatyphylla Community and Its Response to Environmental Factors in Qilian Mountains

为研究祁连山天然白桦林的光合特征及其影响因子,以青海仙米林场典型的天然白桦群落植被(白桦、小檗和珠芽蓼)为研究对象,采用Li-6400X便携式光合测定系统测定了3种植物的净光合速率(Pn)日变化,运用相关性分析和通径分析法研究了3种植物Pn对主要环境影响因子的响应。结果表明,晴天白桦叶片Pn显著高于阴天,小檗叶片Pn晴天高于阴天,珠芽蓼叶片Pn则是晴天低于阴天;晴天白桦和小檗叶片日同化量均高于阴天,珠芽蓼则是阴天显著高于晴天;晴天,白桦叶片Pn的决定因子和限定因子分别为光合有效辐射(PAR)和叶片温度(TL),小檗分别为PAR和相对湿度(RH),珠芽蓼分别为气孔导度(Gs)和TL;阴天,白桦叶片Pn的决定因子和限定因子分别为RH和大气温度(Ta),小檗分别为PAR和RH,珠芽蓼分别为RH和PAR。

To study the photosynthetic characteristics and influencing factors of natural Betula Pllatyphylla forest in Qilian mountains,the diurnal variation of net photosynthetic rate(P n)for typical natural Betula platyphylla community(Betula platyphylla,Berberis kawakamii,Polygonum viviparum)of Xianmi Forest Farm in Qinghai Province was measured by Li-6400X portable photosynthesis system,and the eco-physiological factors were assessed by the correlation analysis and path analysis.The results showed that the P n of Betula platyphylla and Berberis kawakamii in the sunny days were respectively significant higher than those in the cloudy days,but the P n of Polygonum viviparum in the cloudy days was higher than that in the sunny days.Under the sunny day conditions,Betula platyphylla and Berberis kawakamii could accumulate more average daily photosynthetic carbon fixation amounts,but Polygonum viviparum could accumulate markedly higher daily photosynthetic carbon fixation amounts in the cloudy days.In sunny days,the main determinant and limiting factors were respectively PAR and T L for Betula platyphylla,PAR and RH for Berberis kawakamii,and G s and T L for Polygonum viviparum.In cloudy days,the main determinant and limiting factors were respectively RH and T a for Betula platyphylla,PAR and RH for Berberis kawakamii,and RH and PAR for Polygonum viviparum.