针、阔树种液流的耗水特性及影响因素

Water Consumption Characteristics and Influencing Factors of Common Conifer and Broad-leaved Tree Species based on Sap Flow

为探究针、阔叶树种的蒸腾耗水特性,分别以侧柏、油松为针叶树研究对象,以国槐、刺槐阔叶树的研究对象,利用热扩散探针法对其进行连续监测。结果表明:(1)3种天气条件下,针、阔叶树的日变化曲线只在雨天存在差异,针叶树的高峰点少于阔叶树,其受降雨影响较小;而晴、阴天无明显差异,均在晴天呈单峰型,阴天呈双峰型。(2)基于液流得到耗水量为针叶树>阔叶树,各树种在4—10月总耗水量为刺槐(1584.49kg)>国槐(957.54kg)>侧柏(736.93kg)>油松(635.21kg)。(3)环境因子与液流的相关性显示,液流与大气温度、太阳辐射、风速和水汽压亏缺(VPD)均呈显著(Sig<0.01)正相关,与空气相对湿度呈显著(Sig<0.01)负相关。(4)侧柏的最优回归模型中太阳辐射(Sig=0.000<0.01)和VPD(Sig=0.001<0.01)较为显著;油松模型中则是温度(Sig=0.007<0.01)和太阳辐射(Sig=0.000<0.01)较为显著;国槐和刺槐的模型中有3个因子较为显著(Sig<0.01),分别是太阳辐射、相对湿度和VPD。

To reveal the water consumption characteristics of conifer and broad-leaved species,Platycladus orienta⁃lis、Pinus tabuliformis、Sophora japonica and Robinia pseudoacacia.respectively were as the research object of the co⁃nifer and broad-leaved trees,and sap flow of trees was continuously observed by thermal dissipation probe(TDP).Results showed that:(1)Under the three weather conditions,the diurnal variation curves of coniferous and broadleaved in rainy days are different,The peak of conifers is less than that of broad-leaved trees,it shows that conifers are less affected by rainfall.and there is no obvious difference between sunny and cloudy days,diurnal sap flow of tree spe⁃cies were a single peak curve in sunny day,when it is cloudy,diurnal sap flow of tree species were"two-peak"curve.(2)The water consumption of trees based on sap flow was coniferous trees>broad-leaved trees,the total water con⁃sumption of all tree species fromApril to October was Robinia pseudoacacia(1584.49kg)>Sophora japonica(957.54kg)>Platycladus orientalis(736.93kg)>Pinus tabuliformis(635.21kg).(3)The correlation between envi⁃ronmental factors and liquid flow shows:The liquid flow was significantly(Sig<0.01)positively correlated with at⁃mospheric temperature,solar radiation,wind speed and water vapor pressure deficit(VPD),and negatively correlated with air relative humidity(Sig<0.01).(4)In the best regression model of Platycladus orientalis,the solar radiation(Sig=0.000<0.01)and VPD(Sig=0.001<0.01)were more prominent;in the regression model of Pinus tabuliformis,temperature(Sig=0.007<0.01)and solar radiation(Sig=0.000<0.01)was significant;the regression model of Sopho⁃ra japonica and Robinia pseudoacacia only 3 factors are more significant(Sig<0.01),there were solar radiation,rela⁃tive humidity and VPD.