乌鲁木齐市秋季夏橡净光合速率日变化特征与生理生态因子的关系

Diurnal Variation of Net Photosynthetic Rate of Quercus in Autumn in Urumqi City and its Relationship with Physio-ecological Factors

文章以位于乌鲁木齐市的新疆师范大学昆仑校区校园内夏橡单株作为试验材料,采用LI-6400便携式光合测量系统测定自然条件下秋季夏橡的净光合速率(Pn)以及相关生理生态因子的日变化过程,并通过相关分析、多元逐步回归分析和通径分析探讨其Pn与生理生态因子之间的关系。结果表明:秋季夏橡Pn日变化呈"Λ"型的单峰曲线,没有出现"光合午休"现象;Pn与气孔导度(Gs)、蒸腾速率(Tr)呈极显著的正相关关系,与叶片温度(Tl)、空气温度(Ta)和叶片光合有效辐射(PAR)呈显著相关关系,与大气CO_2浓度(Ca)、空气相对湿度(RH)、和胞间CO_2浓度(Ci)呈不显著负相关关系,且相关性递减;Pn与各生理生态因子之间的多元逐步回归方程为:Pn=-4.660+3.102Tr+0.099RH+11.320Ls(R=0.997);影响秋季夏橡Pn的决定生理生态因子为Tr和Ls,其中Tr为主要决定因子,而RH为限制因子。研究发现,秋季时节夏橡仍具有较高的光合作用,探究秋季夏橡净光合速率与其生理生态因子的关系,为西北干旱区绿洲生态建设和城市绿化植被管理提供一定的理论依据。

Taking the Quercus plant in the Xinjiang Normal University campus in Urumqi as the test material,the LI-6400 portable photosynthesis measurement system was used to determine the diurnal variation of the net photosynthetic rate(Pn)and related physio-ecological factors in autumn under natural conditions.And through correlation analysis,multiple stepwise regression analysis and path analysis to explore the relationship between Pn and physio-ecological factors.The results showed that the diurnal change of Quercus Pn in autumn summer was a singlepeak curve of“Λ”type,and there was no phenomenon of“midday break of photosynthetic”;Pn was significantly positively correlated with stomatal conductance(Gs)and transpiration rate(Tr).Leaf temperature(Tl),air temperature(Ta)and leaf photosynthetically active radiation(PAR)were significantly correlated,and were not significant with atmospheric CO2 concentration(Ca),air relative humidity(RH),and intercellular CO2 concentration(Ci).Negative correlation and decreasing correlation;the multivariate stepwise regression equation between Pn and each physio-ecological factor is:Pn=-4.660+3.102Tr+0.099RH+11.320Ls(R=0.997);The physio-ecological factors of Pn are Tr and Ls,where Tr is the main determinant and RH is the limiting factor.The study found that during the autumn season,the Quercus still has high photosynthesis,and the relationship between the net photosynthetic rate of Quercus in autumn and its physio-ecological factors is explored.This can provide a theoretical basis for the ecological construction of the oasis in the northwestern arid region and the management of urban afforestation vegetation.