Research on stem sap flow character of “Fuji” apple trees and the response to main meteological factors | 气象因子对红富士苹果树干茎流特性的影响

Chinese. 利用热扩散茎流测定系统（TDP）连续监测苹果树在生长季的茎流速率，同步观测太阳辐射、空气温度、空气相对湿度和风速等气象因子，选择晴天、阴天两种典型天气分析鲁西南地区苹果树干茎流速率的日变化及其与气象因子的关系。结果表明：苹果树干茎流速率在晴天条件下呈现单峰曲线，阴天条件下呈现多峰曲线。不同天气条件下，苹果树干茎流速率日变化波动曲线及其主要影响因子各异，但太阳辐射始终是茎流速率变化的主导因子。晴天茎流速率的主要影响因子依次为太阳辐射、空气相对湿度和空气温度；阴天依次为太阳辐射和空气温度。蒸腾量日际变化或季节变化特征为4月份逐渐升高、5—6月份达到高峰值、7月份后逐渐降低、10月份达到第二次高峰、11月初迅速降低。主要生长期蒸腾量为708.93mm，其中，主要需水期（5～7月份、10月份）的蒸腾量为423.41mm，占主要生长季的59.72％。

English. Stem sap flow dynamics of Fuji’ apple trees during the growing season with a year in the southwestern of Shandong province were studied by thermal diffusion probe (TDP), and total solar radiation, air temperature, air relative humidity and wind speed were measured by automatic weather recording system synchronously. According to the manual records of weather conditions, two most representative weather conditions (sunny and cloudy days) were gathered up to analyze the relationships of sap flow rate with meteorological factors. The results showed that the change of sap flow rate in sunny days was in a form of single-peak curve and in cloudy days was in multi-peak curve. The diurnal variations of sap flow rate and its dominant affecting factors differed with weather conditions, and solar radiation was always the dominant factor affecting stem sap flow rate. The main factors of stem sap flow rate in sunny days were solar radiation, air relative humidity and air temperature, and in cloudy days they were solar radiation and air temperature. The daily variations of transpiration is characterized with that transpiration rose gradually in April, and reach a peak during May and June, fall down readily in July, reach a second peak in October and descend rapidly in November. The transpiration was 708.93 mm in the main growing season and the main water requirement period (May, June, July and October) was 423.41 mm among them, accounting for 59.72%.