南召宝天曼生境下山茱萸光合生理生态特性研究

Study on Photosynthetic and Eco-physiological Characteristics of Cornus officinalis in the Habitat of Baotianman in Nanzhao County

在完全自然生长不离体的情况下,利用Li-6400测定南召宝天曼生境下山茱萸7月份的光合生理生态指标。结果表明:山茱萸净光合速率日变化呈双峰曲线,具有光合"午休"现象且由非气孔限制因素所致;山茱萸净光合速率与叶片气孔导度、胞间CO_2浓度、气孔限制值呈线性相关,与光合有效辐射呈二次抛物线型相关,与其它生理生态因子之间没有直接的显著相关,但逐步回归多元统计分析显示利用叶片气孔导度和叶片温度二因子预测山茱萸净光合速率精度较高;在叶温28℃和空气CO_2浓度360μmol·mol^(-1)条件下,山茱萸净光合速率随光合有效辐射的增强而提高,光补偿点和光饱和点分别为25μmol·m^(-2)·s^(-1)、1 000μmol·m^(-2)·s^(-1),在此条件下,净光合速率与蒸腾速率和叶片气孔导度没有显著的相关关系,但与胞间CO_2浓度呈二次抛物线型显著相关;在叶温28℃和光合有效辐射900μmol·m^(-2)·s^(-1)条件下,净光合速率随着CO_2浓度的增加而提高,CO_2补偿点和CO_2饱和点分别为100μmol·mol^(-1)、1 400μmol·mol^(-1),此条件下净光合速率与蒸腾速率和胞间CO_2浓度均呈对数曲线显著正相关。

In the case of natural growth and not separated from the body, photosynthetic and eeo-physiological indexes of Comus officinalis growing in the habitat of Baotianman located in Nanzhao county were measured using Li-6400. The results showed that diurnal variations of Pn presented a bimodal curve. The first and second peak appeared at 9：00 and 14：00 respectively. There was photosynthetic midday depression which was caused by non-stomata limitation. Pn of Comus officinalis was linearly correlated with Gs, Ci, Ls, with Par like parabola, and Pn did not evidently correlated with other eco-physiological factors. However, Gs and T1 can precisely predict Pn by the method of regression equation multinomial regression. Pn increased with the enhancement of Par under the conditions of 28C leaf temperature and 360 μmol·mol^-1 CO2 concentration. Light compensation and saturation point were respectively 25 μmol·m^-2·S^-1 and 1 000μmol·m^-2·S^-1. Under these conditions, Pn was not evidently correlated with Tr and Gs, but markedly correlated with Ci like parabola. Pn increased with the enhancing of CO2 concentration under the conditions of 28C leaf temperature and 900 μmol·m^-2·S^-1 photosynthesis active radiation. CO2 compensation point and saturation point were respectively 100 μmol·mol^-1 and 1 400μmol·mol^-1. Under these conditions, Pn was significantly correlated with Tr and Ci which presented logarithmic curve.