复羽叶栾树光合作用日变化及光响应特征

采用LI-6400便携式光合测定系统,测定贵州茅台酒厂生态功能区内复羽叶栾树光合作用日变化及光响应特征,并分析光合生理与生态因子之间的关系.结果表明:复羽叶栾树净光合速率(Pn)、光能利用率(LUE)的日变化均为单峰曲线,Pn和LUE的峰值分别出现在12:00和10:00左右;胞间二氧化碳浓度(Ci)的日变化与Pn相反,蒸腾速率(Tr)和气孔导度(Cond)的日变化均呈逐渐降低的趋势;Pn、Tr、LUE、Ci和Cond与主要环境因子光合有效辐射(PAR)、大气温度(Ta)和相对湿度(RH)之间的关系均符合二次曲线的变化规律,其中Pn、Tr与PAR、Ta、RH的相关程度均达极显著水平,Cond与PAR、Ta、RH的相关程度均达显著水平,LUE与PAR、Ta的相关程度均达极显著水平;PAR是影响复羽叶栾树Pn、Tr、Ci和Cond最主要的环境因子,LUE主要受Ta的影响.

Diurnal variation of photosynthesis and response to light intensity of Koelreuteria bipinnata

Diumal changes of photosynthesis and light response curve of Koelreuteria bipinnata were measured with LI-6400 in ecological function zones of Moutai winery, and the relationship between photosynthetic physiology and ecological factors were analyzed. The results showed that the net photosynthetic rate (Pn) and light use efficiency (LUE) of K. bipinnata had the diurnal variation of single peak, which appeared around 12:00 a.m. and 10:00 a.m. respectively. Intercellular CO2 concentration (Ci) had opposite diurnal variation, compared with Pn. Diurnal variation of transpiration rate(Tr) and stomatal conductance(Cond) had gradual decrease on the whole day. The relationship among Pn, Tr, LUE, Ci, Cond and photosynthetical active radiation (PAR), air temperature (Ta), relative humidity (RH) had characteristics of quadratic curve model. There was a significant correlation between Pn, Tr and PAR, Ta, RH. A correlation between Cond and PAR, Ta, RH was observed. At the same time, a siginificant correlation between LUE and PAR, Ta was also observed. PAR was the most sensitive enrironmental factor to Pn, Tr, Ci and Cond of K. bipinnata and LUE was mainly effected by Ta.