中国12种珍稀树种光合生理特性

Photosynthetic Characteristics of Twelve Rare Tree Species in China

以中国12个珍稀树种为研究对象,采用Li-6400型便携式光合作用测定系统测定了12个树种光合作用对光的响应特征及其7、11月份光合作用的日变化规律,阐述了其光合作用对光的响应特征和光合作用日变化的季节性特征。结果表明:非直角双曲线模型可较好地模拟12个珍稀树种的光响应曲线,得出一系列光合响应特征参数(表观量子效率、最大净光合速率、暗呼吸速率、光饱和点、光补偿点等)存在显著的差异;12个珍稀树种的表观量子效率、最大净光合速率、暗呼吸速率、光饱和点、光补偿点大小范围分别为0.0355～0.0684mol·mol-1、6.474～18.537μmol·m-2·s-1、-1.844～-0.732μmol·m-2·s-1、644～1330μmol·m-2·s-1、13.4～40.6μmol·m-2·s-1;不同珍稀树种的叶片蒸腾速率在光照强度为0～1800μmol·m-2·s-1时呈上升趋势;水分利用效率随着光照强度的增大呈现出先上升后下降的趋势;12种珍稀树种在7月份光合速率的日变化趋势基本相同,均在日变化进程中出现2个高点,有明显的光合"午休"现象,而在11月份这12个树种的净光合速率的日变化进程中只有一个高点,无明显的光合"午休"现象,且7月份的净光合速率整体高于11月份。

Li-6400 was used to measure the photosynthetic light-response curves and the daily patterns of photosynthesis of 12 rare tree species in China in July and November.The characteristics of the photosynthetic responses to light intensities and the seasonal pattern for the daily change of photosynthesis were analysed.Result showed that non-rectangular hyperbola model could well simulate the light response curves of the 12 species of plants.There were significant differences in apparent quantum yield of photosynthesis（α）,maximum net photosynthesis rate（Pmax）,dark respiration rate（Rd）,light compensation point（LC,P）,and light saturation point（LS,P） between the 12 species of plants.The variation ranges of α,Pmax,Rd,LS,P,LC,P were 0.035 5 ～ 0.068 4 mol·mol-1,6.474 ～ 18.537,-1.844 ～-0.732,644 ～ 1 330 and 13.4 ～ 40.6 μmol·m-2·s-1.The transpiration rate（Tr） of the 12 tree species increased linearly with increasing light intensity ranging from 0 to 1 800 μmol·m-2·s-1,while the water use efficiency increased rapidly at first and then decreased slowly.All the species exhibited the same pattern of daily change in photosynthesis in July,and there were two peaks and an obvious midday depression phenomenon.The daily change of net photosynthetic rate exhibited one peak in November,and the net photosynthetic rates of the 12 rare tree species in July were higher than those in November.