南方红豆杉蒸腾强度与生态因子的关系

采用“三次称重法”测定南方红豆杉(Taxus chinensis var．mairei(Lemee et level)Cheng et L K Fu)换叶期蒸腾强度日变化、月变化,同步定点定位测定生态因子的变化,运用一元线性回归、多元回归分析蒸腾强度与生态因子的关系。结果表明：蒸腾强度日进程呈现早晚低、中午高的曲线,3月与4月为双峰,5月为单峰,即从3月到5月经历由轻蒸腾午休型到非蒸腾午休型的转变;蒸腾作用受生态因子的综合影响,与光照强度和气温显著正相关,与相对湿度显著负相关,其中光照强度影响最大,其次是气温和湿度;不同月份的蒸腾强度差异达到显著水平,引起这种差异的主导生态因子是气温。

Correlation between Ecological Factors and Transpiration Intensity of Taxus chinensis var. mairei

The daily and monthly changes of transpiration intensity of Taxus chinensis var.mairei (Lemee et level )Cheng et L.K.Fu in changing leaves stage were measured with the method of"weighing three times" from March toMay, and the variations of some ecological factors at fixed locations and positions were determined at the same time.Then,the correlation between transpiration intensity of Taxus chinensis var.mairei and environmental factors wasanalyzed by linear regression and multiple regression. The results showed that the diurnal changes of transpirationintensity of Taxus chinensis var. mairei were lower in the morning and evening and higher at noon. The shape ofinverted saddle changed on a daily basis; It had weak midday depression in March and April, which took on adouble-ridged curve,with the peak value appearing at 13:00 and 14:00. It did not have obvious midday depressionin May,which took on a single-ridged-form,with the peak value appearing at 13:00.The transpiration intensity ofTaxus chinensis var. mairei was affected by lots of ecological factors. The transpiration intensity has significantpositive correlation with light intensity ( LI), air temperature (AT) and has significant negative correlation withrelative humidity ( RH). The order of the factors in term of importance was: LI > AT > RH. The transpirationintensity in different months was different to a large extent. Their changes were influenced mainly by the change ofair temperature.