西南地区野生岩柿的光合与水分生理特征

The Photosynthetic and Water Physiological Characteristics of Wild Diospyros dumetorum in the Southwest Region

以中国西南地区野生岩柿幼苗(Diospyros dumetorum W.W.Smith)为试验材料,探讨岩柿光合与水分生理特征规律,以期为岩柿资源保护、西南地区乡土植物群落修复提供理论和技术支持。分别使用Li-6800便携式光合测定仪和露点水势仪对光合生理指标和叶水势日变化进行测定,苗期岩柿叶片光饱和点为856.7919μmol·m^(-2)·s^(-1),光补偿点为20.4177μmol·m^(-2)·s^(-1),最大净光合速率为9.9469μmol·m^(-2)·s^(-1);其净光合速率主要与大气温度(T_(a))、气孔限制值(L_(s))、叶肉瞬时羧化效率(M_(CE))、蒸腾速率(E)、水分利用效率(W_(UE))、气孔导度(G_(s))影响因子呈正相关,叶片水势与大气温度(T_(a))、大气湿度(R_(H))与光合有效辐射(P_(AR))环境因子有密切关系,苗期岩柿光适应范围较窄,光饱和点及光补偿点偏低,在温度较高、湿度较低、光辐射强的环境下岩柿幼苗吸水能力减弱,使得其幼苗在光辐射强、植被覆盖率低的西南地区较为少见,因此,岩柿更适宜在适度遮荫的林下空间生长,在西南地区进行乡土植物岩柿的培育及经营管理时应进行合理植物配置、建立多层次林分结构,为岩柿幼苗提供一定遮光、降温、增湿的作用,将有助于其发挥更大的生态效益。

Using wild Diospyros dumetorum W.W.Smith seedlings from the southwest region of China as experimental materials,this study explores the rules of photosynthetic and water physiological characteristics of D.dumetorum,aiming to provide theoretical and technical support for the protection of D.dumetorum resources and the restoration of indigenous plant communities in the southwest region.The portable Li-6800 photosynthesis measurement in-strument and dew point water potential meter were used to measure the photosynthetic physiological indicators and daily changes in leaf water potential.The results showed that the leaf light saturation point of D.dumetorum seedlings was 856.7919μmol·m^(-2)·s^(-1),the light compensation point was 20.4177μmol·m^(-2)·s^(-1),and the maximum net photosynthetic rate was 9.9469μmol·m^(-2)·s^(-1).The net photosynthetic rate of D.dumetorum seedlings was mainly positively correlated with atmospheric temperature(T_(a)),stomatal limitation value(L_(s)),instantaneous carboxylation efficiency of leaves(M_(CE)),transpiration rate(E),water use efficiency(W_(UE)),and stomatal con-ductance(G_(s)).Leaf water potential was closely related to atmospheric temperature(T a),atmospheric humidity(R_(H)),and photosynthetically active radiation(P_(AR))environmental factors.D.dumetorum seedlings have a narrow range of light adaptation,with low light saturation and compensation points.In environments with high temperatures,low humidity,and strong light radiation,the water absorption capacity of D.dumetorum seedlings is weakened,making them less common in the southwest region with strong light radiation and low vegetation cover.Therefore,D.dumetorum is more suitable for growing in moderately shaded understory spaces.When cultivating and managing D.dumetorum in the southwest region,rational plant configuration and establishment of multi-layered forest structure should be carried out to provide D.dumetorum seedlings with certain shading,cooling,and humidifying effects,which will help them to exert greater ecological benefits.