冀北沙荒地黄柳光合与蒸腾速率日变化特征

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0.220μmol/(m2·s);中坡黄柳光合速率日最大值、日均值分别为0.290和0.210μmol/(m2·s);上坡黄柳光合速率日最大值、日均值分别为0.350和0.220μmol/(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。

Diurnal Variation Characteristics of Photosynthesis and Transpiration Rate of Salix gordejevii in Sandy Land of Northern Hebei

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 gro dejevii in different slope by using Li-6400 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 P n in the downslope was 0.340μmol/(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 0.210 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.