虎榛子光合特征变化及其与主要影响因子的关系

PHOTOSYNTHETIC CHARACTERISTICS OF Ostryopsis davidiana Decaisne AND RELATIONSHIP WITH MAIN INFLUENCING FACTOR

本文以大青山南坡山区虎榛子(Ostryopsis davidiana Decaisne)为材料,使用LI-COR6400便携式光合仪、AP4动态气孔计测定系统实地测定了其7月～10月叶片净光合速率(Pn)、蒸腾速率(Tr)、水分利用效率(WUE)等日进程变化。结果表明虎榛子Pn日变化呈双峰型曲线,Tr呈单峰曲线,第一峰都出现在10:00。水分利用效率日变化与光合速率、蒸腾速率变化趋势相反,月变化趋势与光合速率一致与蒸腾速率相反,呈现高温干旱7月份WUE较高的特点,该月具有较高的光合速率、较低的蒸腾速率。对其光合作用生理因子和环境因子进行线性回归分析表明虎榛子Pn、Tr等变化主要受光照、大气水分亏缺和气孔导度的影响。Pn月变化表明,在虎榛子年生长最大月份7月和8月,受干旱的影响其光合速率呈现不规律变化,明显与叶绿素含量相关。

The diurnal variation of photosynthetic rate（ Pn）, transpiration rate（Tr） and water use efficiency（WUE） of Ostryopsis davidiana Decaisne were measured by using LI - 6400 portable photosynthetic system and AP4 dynamic stomatal analyzer in July to October in the south slope of Daqing Mountain. The results indicated that diurnal course of Pn and Tr of Ostryopsis davidiana have double peak and single peak respectively, which first peak are at 10：00. The diunaal variation trend of WUE is contrary with that of Pn and Tr. The diurnal variation trend of W UE is similar with that of Tr, but monthly variation of WUE is similar with that of Pn and contrary with that of Tr, it has high value in July which has high temperature and drought. Pn has higher value and Tr has lower value in July. We analyzed the linear regression between physiological and environmental factors which influence the photosynthesis significantly and the result showed the main factors affecting the characteristics of Pn and Tr of Ostryopsis davidiana are photosynthetic active radiation （PAR） ,saturation vapor pressure（VPD） and stomatal conductance（Gs）. The monthly variation of Pn shows irregular change obviously in July and August, which is influenced by drought and related with chlorophyll.