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作 者 ：张淑勇,周泽福*,张光灿,夏江宝

期 刊 ：生态学报 2009年 29卷 1期 页码：499~507

关键词：黄土丘陵区；山桃；山杏；气体交换；日变化；环境因子；

Keywords:Loess hilly-gully region, Prunus davidiana, Prunus sibirica L., Leaf-gas exchange, Diurnal change, Environmental factors,

摘 要 ：以半干旱黄土丘陵区5年生天然次生灌木山桃（Prunus davidiana）及山杏（Prunus sibirica L.）作为研究材料，系统比较了两树种叶片气体交换参数的日变化特征，分析了其光合作用和蒸腾作用与环境因子的关系。结果表明：山桃叶片气体交换参数日变化特征与山桃有所差异，山桃除蒸腾速率（Tr）外其它生理参数呈单峰曲线，山杏的日变化类型均呈双峰曲线。两树种光合速率（Pn）在下午明显下降，其原因主要是受到非气孔限制。山桃Pn的日均值（(7.64±3.69) μmol·m-2·s-1）比山杏（(529±2.97) μmol·m-2·s-1）高出46％，Tr的日均值（(2.21±1.02) mmol·m-2·s-1）比山杏（(1.58±0.57) mmol·m-2·s-1）高出40％左右，水分利用效率（WUE）的日均值相差不大，分别为(2.89±1.52) μmol·mmol-1，(2.54±1.37) μmol·mmol-1。多元回归及相关分析表明，影响光合作用与蒸腾作用的最重要因子是光合有效辐射强度，其次是大气CO2浓度；光合作用与蒸腾作用参数之间也有明显的相关性。结论：山桃与山杏表现出具有较高光合速率，较低蒸腾速率和较高水分利用效率的生理特征，因而在半干旱黄土丘陵区都有较好引种栽培与开发利用潜力。

Abstract:In this study, two naturally regenerated, five-year old shrubs, Prunus davidiana and Prunus sibirica L., in semi-arid and hilly-gully loess region were used to investigate their characteristics of gas exchange and the relationship with the environment. The study intended to provide a scientific basis for the rational allocation in vegetation construction. The temperature (Tc), CO2 concentration (Ca), and relative humidity (RH) in the air and photosynthetically available radiation (PAR) at the leaves′ levels were recorded with Li-6400. The diurnal courses of their net photosynthetic rate (Pn), transpiration rate (Tr), intercellular CO2 concentration (Ci) and stomatal conductance (Gs) were measured in the field in the Chemingyu Forest Station in Shanxi, China (111°04′～111°21′ N，37°03′～37°20′ E). The results showed that the diurnal change in characteristics of leaf-gas exchange parameters was different between P. davidiana and P. sibirica L. All measured physiological parameters, except transpiration rate (Tr), of P. davidiana exhibited a single peak of diurnal changes, while the style of diurnal change of P. sibirica L. in all measured physiological parameters presented double peaks. The decline of net photosynthetic rate (Pn) in afternoon was mainly caused by non-stomatal limitation. The daily average Pn ((7.64±3.69) μmol?m-2?s-1) of P. davidiana was 46% higher than that ((529±2.97) μmol?m-2?s-1) of P. sibirica L., and the daily Tr ((2.21±1.02) mmol?m-2?s-1) was about 40% higher than that ((1.58±0.57) mmol?m-2?s-1) of P. sibirica L., and the daily water use efficiency was not significantly different between P. davidiana and P. sibirica L., and was respectively (2.89±1.52) and (2.54±1.37) μmol?mmol-1. Correlation analysis and regression analysis showed that the photosynthetic active radiation (PAR) had the greatest effect on photosynthesis and transpiration, and CO2 concentration in field (Ca) played the second role. In addition, the photosynthetic parameters themselves had obvious correlations with each other. It was concluded that P. davidiana and P. sibirica L. all put up higher Pn and WUE, and lower Tr physiological characteristics, thus they had better potentialities in Exploitation and utilization, and introduction and cultivation in semi-arid Loess Hilly region.

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