成熟马占相思林的蒸腾耗水及年际变化  

Water consumption and annual variation of transpiration in mature Acacia mangium Plantation

作　　者：赵平[1] 邹绿柳[1] 饶兴权[1] 马玲[1] 倪广艳[1] 曾小平[1] 蔡锡安[1] 

机构地区：[1]中国科学院华南植物园,广州510650

出　　处：《生态学报》2011年第20期6038-6048,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30871998;41030638)

摘　　要：利用Granier测定系统对华南丘陵植被恢复先锋群落马占相思林的树干液流进行了连续4a(2004—2007年)的监测研究,以了解已过生长高峰的马占相思林(20—22林龄)的水分利用特征。结果显示,液流密度(Js)日变化为单峰型曲线,具有明显的季节差异,湿季Js日变化幅度和峰值Jsmax均大于干季。Js与光合有效辐射(PAR)和水汽压亏缺(VPD)的偏相关分析显示,Js与PAR或VPD正相关,干季的相关性较湿季显著;线性回归分析显示PAR和VPD对Js日变化共同影响的程度达62.7%—82.7%。马占相思整树和林分的蒸腾强度和耗水量均表现出明显的干湿季差异,湿季明显高于干季。偏相关分析表明降雨量对蒸腾活动没有显著的直接影响,而PAR与蒸腾量显著相关,是影响林分蒸腾量的最重要环境因子。2004—2007年各年马占相思成熟林的蒸腾耗水量为238.64、136.39、217.45mm和273.85mm,分别占当年降雨量的24.7%、11.7%、9.8%和22.8%,年平均蒸腾耗水量为243.31±28.49 mm(n=3),降水对林分蒸腾的影响不仅仅取决于降雨量的大小,较多的降雨频次往往会削弱蒸腾的强度。研究的马占相思林处于生长后期,群落叶面积指数和蒸腾已有明显的下降,反映出该阶段林分已不能充分利用当地的辐射和水分资源,必要的林分改造可提高造林后期的生产效益。Granier′s sap flow measuring system was applied to monitor sap flow of Acacia mangium plantation,the pioneer community of re-vegetation in South China′s hilly land,for four consecutive years（2004—2007）.We aimed at understanding water use by the 20—22 year old A.mangium stand that had already passed the peak period of growth.Results showed that the diurnal change pattern of sap flux density（Js） presented a unimodal curve with distinct differences between wet seasons（WS） and dry seasons（DS）.The sap flow in WS was obviously more dynamics than that in DS,and the peak values of Js（Jsmax） during WS were higher than DS.Partial correlation analyses showed that Js was significantly correlated with PAR or VPD,and such correlation for DS was much more significant than WS.Linear correlation analyses indicated that the combined effects of PAR and VPD on diurnal changes of Js attained 62.7%—82.7%.For the whole tree and stand transpirations,marked differences between WS and DS were observed in A.mangium,where the transpiration during WS was higher than DS.Partial correlation analyses indicated that there was no direct significant effect of precipitation on stand transpiration,while PAR was significantly correlated with transpiration and hence the most influential environmental factor on stand transpiration.Annual water consumption by transpiration of A.mangium plantation from year 2004 to 2007 was 238.64,136.39,217.45 and 273.85mm,which merely accounted for 24.7%,11.7%,9.8% and 22.8% of precipitation for each year,respectively.The annual mean transpiration of A.mangium plantation was（243.31±28.49） mm（n=3）.Influence of precipitation on stand transpiration did not merely depend on the rainfall intensity,since an increase in rainfall frequency often reduced the whole year＇s transpiration.Since the studied A.mangium plantation was in its late stage of growth with a lower canopy leaf area index and transpiration,the current forest stand could not fully and effectively utilize the local resour

关 键 词：树干液流 马占相思 林分蒸腾 Granier液流探针 

分 类 号：S718.5[农业科学—林学]