不同灌木树种蒸腾速率时空变异特征及其影响因子的研究

在测定4个水土保持灌木树种不同时期蒸腾速率及其影响因子的基础上,对不同树种蒸腾速率的时空变异特征进行了研究,并对蒸腾速率与其影响因子的关系进行了相关分析和多元回归分析。研究结果表明,4种灌木蒸腾速率日变化总趋势为清晨较小,在中午12:00左右基本达到峰值,至18:00左右降至低谷,不同树种日变化有一定差异;旱季4种灌木蒸腾速率的大小顺序为黄荆>黄栌>连翘>绣线菊;雨季4种灌木蒸腾速率的大小顺序为黄荆>绣线菊>连翘>黄栌。4种灌木蒸腾速率的季节变化趋势基本相同,均在5月份呈降低趋势,从6月初又逐渐回升,在7月中旬达到最大值后回落。蒸腾速率在空间上的变化特征是上部最大,中部次之,下部最小。4种灌木的蒸腾速率均与光合有效辐射、气温、空气相对湿度以及气孔导度4个因子呈极显著相关。

Study on Characteristic of Temporal and Spatial Variability of Transpiration Rate of Different Bushes and Its Influencing Factors

This paper analyzed the daily variability and the seasonal variability and spatial variability of the transpiration rate of four kinds of bushes in soil and water conservation, and the correlation analysis and multi-regression analysis were applied to their transpiration rate and influencing factors. The results of the study were the following. The total tendency of the daily variability of four kinds of bush transpiration rate was that it was relatively small in early morning and it reached peak value basically at about 12:00 at noon and dropped to the utmost point from side to side low by 18:00. The change had certain differences on different bushes. According to peak value of the transpiration rate, the size order of the transpiration rate of the four kinds of bushes in dry season was Vitex negundo Linn.> Cotinus coggygria Scop. > Forsythia suspense (Thunb.) Vahl.> Spriaea trilobata Linn.,and it was Vitex negundo Linn. > Spriaea trilobata Linn. > Forsythia suspense (Thunb.) Vahl.> Cotinus coggygria Scop. in rainy season. The variability tendency of season of four kinds of bush transpiration rate was the same basically. It showed a tendency to reduce in May and then went up gradually since the beginning of June and reached the maximum in mid-July and then began to fall after rise shortly afterwards. The characteristic of spatial variability of transpiration rate was that the largest transpiration rate on top and the middle part takes second place, and the under-part is minimum. The transpiration rate of four kinds of bushes extremely remarkable had with the effective radiation, temperature, air relative humidity and air vent is it spends four extremely remarkable correlations.