%0 Journal Article
%T Characteristics of spatial variations in xylem sap flow in urban greening tree species Pinus tabulaeformis, Cedrus deodara and Robinia pseudoacacia in Beijing, China<br>北京绿化树种油松、雪松和刺槐树干液流的空间变异特征
%A WANG Hua
%A OUYANG Zhi-Yun
%A ZHENG Hua
%A WANG Xiao-Ke
%A NI Yong-Ming
%A REN Yu-Fen
%A <br>王华
%A 欧阳志云
%A 郑华
%A 王效科
%A 倪永明
%A 任玉芬
%J 植物生态学报
%D 2010
%I Editorial Office of Chinese Journal of Plant Ecology
%X Aims Water consumption of urban plants with multiple ecological effects is important. However, large errors may occur when sap flow is scaled from single point measurement to whole tree without knowledge of spatial sap flow profiles in the trunk. Our objective was to investigate the spatial variation of sap flux density (Js) and its possible cause to estimate whole-tree water use more precisely. Methods Spatial patterns of sap flux density in the sapwood of Pinus tabulaeformis, Cedrus deodara and Robinia pseudoacacia were investigated with thermal dissipation probe from June to November 2008 in Beijing, China. Important findings Axial variation was substantial. Due to greater exposure to sun in the south aspect, the anatomy of the xylem structure and lower branch height, there was an apparent relationship between sap flux density and aspect in P. tabulaeformis and C. deodara, but no apparent relationship in R. pseudoacacia. Hourly Js over 24 h at different aspects were highly correlated; therefore, mean Js may be accurately estimated based on measurement obtained on one aspect. Js showed marked radial variation within the trunk. Js at different depths show similar diurnal pattern, while Js at deeper depth lagged behind and was more sensitive to evaporative demand than the shallower depth. Hourly Js over 24 h at different depths were highly correlated, so Js at a particular depth could be extrapolated as a multiple of Js at the depth of 15 mm. However, depth profiles of Js differed among aspects within a tree. Js at the deeper depth on the south aspect of C. deodara was greater and had no time lag compared to other aspects. In conclusion, sap flux density on the north side at depths of 15 and 70 mm could give an accurate estimation of whole-tree transpiration.
%K Cedrus deodara
%K Pinus tabulaeformis
%K radial an<br>雪松
%K 油松
%K 方位和径向变异
%K 刺槐
%K 热消散探针法
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=2F2173CCFF292BF447DC2681EA33BBAE&aid=405B13863E925A41C0A87CBCB6C8411B&yid=140ECF96957D60B2&vid=339D79302DF62549&iid=5D311CA918CA9A03&journal_id=1005-264X&journal_name=植物生态学报&referenced_num=0&reference_num=27