东北地区四种常见灌木的光合和蒸腾特性研究

Photosynthesis and Transpiration Characteristics of Four Common Shrub Vegetation in Northeast of China

以东北地区常见的园林绿化灌木东北连翘(Forsythia mandshurica)、毛樱桃(Cerasus tomentosa)、小叶丁香(Syringa microphylla)及东北山梅花(Philadelphus schrenkii)为研究对象,于2013年8月使用Li-Cor 6400便携式光合测定系统对其光合蒸腾特性进行了研究,并对净光合速率(Pn)、蒸腾速率(Tr)及其相关生理生态因子进行了相关性分析。结果表明:毛樱桃、小叶丁香的Pn、Tr日变化规律表现为单峰曲线;东北连翘Pn日变化呈单峰曲线,Tr日变化呈双峰曲线,有"午休"现象;东北山梅花Pn的日变化呈双峰曲线,出现"午休"现象,Tr日变化呈单峰型。影响4种灌木的Pn、Tr的主要生理因子是气孔导度(Cond)、胞间CO2浓度(Ci),Pn、Tr与Cond呈极显著正相关(P<0.01),与Ci均呈显著负相关(P<0.05)。光合蒸腾速率与光合有效辐射(PAR)、空气CO2浓度(Ca)、空气相对湿度(RH)等环境因子存在紧密联系,PAR是促进Pn的主要环境因子,而Ca常常成为主要的限制因素。

An experiment was conducted to study the photosynthesis and transpiration characteristics of Forsythia mandshurica,Cerasus tomentosa,Syringa microphylla and Philadelphus schrenkii in Northeast of China by using the Li-Cor 6400 portable photosynthesis system.The correlation analysis among net photosynthetic rate,transpiration rate and their related physiological and ecological factors were made respectively.The results showed that the diurnal change of net photosynthetic rate and transpiration rate of Cerasus tomentosa（Thunb.）Wall.and Syringa microphyllashowed one-peak type.The diurnal change of net photosynthetic rate of Forsythia mandshurica Uyeki showed one-peak type and transpiration rate showed two-peak type,while those of Philadelphus schrenkii Rupr.exhibited a typical bimodal curve and one-peak type.The main physiological factors of net photosynthetic rate and transpiration rate were stomatal conductance and intercellular CO2 concentration.Photosynthetic rate and transpiration rate of 4shrubs were positively correlated with stomatal conductance,and negatively correlated with intercellular CO2 concentration.Photosynthetic rate and transpiration were closely related to photosynthetically active radiation,air CO2 concentration and air relative humidity.Photosynthetically active radiation was the main positive ecology factor affecting photosynthesis,while intercellular CO2 concentration and air CO2 concentration were the main negative factors.