蔺鑫 刘歌畅 杨晔

摘要[目的]探讨不同坡位黄柳光合与蒸腾的日变化规律，明确不同坡位黄柳光合生产与蒸腾耗水的关系。[方法]以冀北沙荒坡地黄柳沙障为研究对象，采用LI-6400光合测定仪，测定不同坡位黄柳光合、蒸腾及其光合有效辐射、气温、叶面温度的日变化，并以光合、蒸腾速率计算水分利用效率日变化数据。[结果]不同坡位黄柳光合速率（Pn）日变化有差异。下坡黄柳光合日变化为双峰曲线。中坡光合为下降曲线。上坡黄柳光合日变化呈现曲折下降趋势。下坡黄柳光合速率日最大值、日均值分别为0.340和0.220 μmol/（m2·s）；中坡黄柳光合速率日最大值、日均值分别为0.290和0.210 μmol/（m2·s）；上坡黄柳光合速率日最大值、日均值分别为0.350和0.220 μmol/（m2·s）。[结论]研究结果为提高冀北沙漠化土地黄柳防风固沙功能及其黄柳资源的合理利用提供了理论依据。

关键词 冀北沙荒地；黄柳；净光合速率；蒸腾速率；日变化

中图分类号 S718.43 文献标识码 A 文章编号 0517-6611（2017）27-0006-04

Abstract [Objective] The aim was to reveal the diurnal variation characteristics of photosynthesis and transpiration rate of Salix gordejevii in different slopes， and the relationship between photosynthesis and water consumption for transpiration. [Method] We took the sand barrier by Salix gordejevii in sand slope of northern Hebei as the research object， measured diurnal variation of photosynthesis， transpiration and PAR， atmospheric temperature and leaf surface temperature of Salix gordejevii in different slope by using Li6400 portable photosynthesis system， the diurnal variation of water use efficiency was calculated by photosynthesis and transpiration rate. [Result] The diurnal variation photosynthetic rate were different in different slope positions. Diurnal variation of photosynthesis in downslope presented a bimodal curve， that in mesoslope presented downtrend curve， and that in upslope presented downward trend. The daily maximum of Pn in the downslope was 0.340 μmol/（m2·s） and the daily average was 0.220 μmol/（m2·s）. The daily maximum of Pn in mesoslope was 0.290 μmol/（m2·s）， and the daily average was 0210 μmol/（m2·s）. The daily maximum of Pn in upslope was 0.350 μmol/（m2·s）， and the daily average was 0.220 μmol/（m2·s）. [Conclusion] The results provide theoretical basis for improving wind and sand control function of Salix gordejevii in northern Hebei sandy land and the reasonable use of Salix gordejevii resources.

Key words Northern Hebei sandy land；Salix gordejevii；Net photosynthetic rate；Transpiration rate；Diurnal change

冀北承德地區是围绕京津的主要生态屏障之一，属国家京津风沙源治理工程建设区。在该区域的沙漠化土地上开展植被恢复与重建，是防治沙漠化最主要和最基本的措施，然而由于该区域沙漠化土地均为沙荒坡地，而不同坡位植物生存的微环境是不一样的，一般而言，坡顶条件更为严酷，因此分析不同坡位植物生理生态特性，对了解沙荒坡地不同部位植物防沙固沙功能及其植被配置有实践指导意义。

黄柳（Salix gordejevii）是杨柳科柳属的一种旱中生……