重庆地区加拿利海枣夏季光合日变化与主要环境因子的关系

Diurnal changes in summer photosynthetic rate of Phoenix canariensis in relation with environmental factors in Chongqing,Southwestern China

于2010年7月中旬采用Li--6400便携式光合仪研究了夏季加拿利海枣净光合速率(Pn)和蒸腾速率(Tr)的日变化规律,探讨了Pn、Tr与主要环境因子的关系。结果表明:加拿利海枣Pn日变化为双峰型,有明显的"午睡"特征,为非气孔限制因素所致;Tr日变化则为单峰型。加拿利海枣具有较高的光补偿点(LCP)和光饱和点(LSP),分别约为34.30和1526.96μmol/(m2·s),表观量子效率(AQY)约为0.034,为典型的阳生植物。相关分析、通径分析和决策系数分析显示:主要环境因子对Pn日变化直接作用大小为空气CO2浓度(Ca)>光合有效辐射(PAR)>空气相对湿度(RH),其中起主要决策作用的因子为Ca,主要限制性因子为RH;对Tr日变化直接作用大小为叶片温度(tl)>RH>PAR>Ca>胞间CO2浓度(Ci),其中起主要决策作用的因子为PAR,主要限制性因子为tl。

Diurnal changes in the net photosynthetic rate （P） and transpiration rate （Tr ） of Phoenix canariensis were studied using the Li-6400 photosynthesis system in mid-July of 2010. The relationship between Pn, Tr and environmental factors was analyzed by correlation coefficient analyses, path coefficient analyses and decision coefficient analyses for a purpose of providing a theoretical understanding of the photosynthetic physio-ecology of P. canariensis to facilitate the introduction and cultivation of this species. Diurnal changes of P,1 had two peaks, occurring in the morning and afternoon, with a midday depression of photosynthesis. The reduction in Pn at midday originated from non-stomatal limiting factors. In contrast to Pn, Tr had only one peak. The light compensation point （LCP） was 34.30 μmol/（m^2·s） and light saturation point （LSP） 1 526.96 μmol/（ m^2 s） , indicating that P. canariensis is a typical heliophyte. The apparent quantum yield （AQY） was 0. 034. The direct impact of environmental factors on Pn occurred in the order of Ca〉 PAR 〉 RH, and t1〉 RH 〉 PAR 〉 C 〉 Ca on Tr. Ca was the primary determining factor and RH the main limiting factor for P ; while PAR was the primary determining factor and tl the main limiting factor for Tro