猕猴桃树干液流特征及其对环境因子的响应

Sap Flow Characteristics of Kiwifruit and Its Response to Environmental Factors

【目的】探明环境因子对猕猴桃树液流特征的影响,为科学制定猕猴桃树灌溉方案提供依据。【方法】以2023年生长季(4—9月)的6年生猕猴桃树为试材,采用热扩散法对猕猴桃植株液流进行1个生长季的连续测量,结合气象及土壤数据分析环境因素(气温、降水、辐射、蒸汽压亏缺、土壤湿度和温度等)与猕猴桃植株液流的关系。【结果】生长季猕猴桃树干平均液流速率为43.607~355.775 g/h,液流日累积量7月>6月>8月>9月>5月>4月。不同月份猕猴桃树液流特征存在相似性,0:00—24:00呈低-高-低变化趋势。不同天气条件下小时尺度果树液流速率规律相同,但树干液流速率峰值存在差异,表现为晴天>阴天>雨天,且晴天、阴天和雨天条件下树干液流速率与太阳净辐射强度(Rn)、水汽压亏缺(VPD)、20 cm土壤温度(T)均呈正相关关系,与空气相对湿度(H)均呈负相关关系。晴天、阴天、雨天树干液流速率与4个环境因子的多元回归拟合方程分别为F=4894.222+8.078e^(-5)Rn+284.579VPD-256.581T+10.019H(R^(2)=0.866)、F=-5220.102+3.410e^(-5)Rn+288.798VPD+181.098T+9.861H(R^(2)=0.855)、F=-2345.668+9.976e^(-6)Rn-4.915VPD+103.162T-0.482H(R^(2)=0.568)。【结论】猕猴桃树耗水量在不同月份、不同天气条件下存在明显差异,7月、8月晴天猕猴桃树干日蒸腾量最大,可适当蓄水、增加灌溉。

【Objective】The influence of environmental factors on the sap flow characteristics of kiwifruit trees were studied to provide support for scientifically planning the irrigation of kiwifruit trees.【Method】Taking the 6-year-old kiwifruit trees in the 2023 growth season as the study object,the sap flow data were measured in 1 growth season by using thermal diffusion method.And combined with the meteorological and soil data,the relationship between environmental factors(temperature,precipitation,radiation,vapor pressure deficit,humidity and temperature of soil,etc.)and the sap flow of kiwifruit was analyzed.【Result】The average sap flow rate of kiwifruit tree ranged from 43.607 to 355.775 g/h,and the daily cumulative amount of kiwifruit sap flow showed as in July>June>August>September>May>April.There were similarities among the sap flow characteristics of kiwifruit trees grown in different months,and showed the trend of low-high-low from 0:00 to 24:00.The rule of hourly sap flow rate of kiwifruit trees under different climate conditions was similar,while there were differences in the peak of sap flow rate in sunny day>cloudy day>rainy day.The sap flow rates in sunny day,cloudy day and rainy day were positively correlated with the net radiation(Rn),vapor pressure deficit(VPD)and temperature of soil at 20 cm(T),but were negatively correlated with the relative air humidity(H).The multiple regression equation of sap flow rate in sunny day,cloudy day and rainy day and 4 environmental factors was F=4894.222+8.078e^(-5)Rn+284.579VPD−256.581T+10.019H(R^(2)=0.866),F=−5220.102+3.410e^(-5)Rn+288.798VPD+181.098T+9.861H(R^(2)=0.855),F=−2345.668+9.976e^(-6)Rn−4.915VPD+103.162T−0.482H(R^(2)=0.568),respectively.【Conclusion】The water consumption of kiwifruit varies in different months and under different weather conditions are different.The daily transpiration on sunny days in July and August are the largest,indicating that water can be stored appropriately and irrigation can be increased.