中国水土保持科学2017，Vol.15Issue(1)：62-70,9.DOI:10.16843/j.sswc.2017.01.008
光温条件和土壤湿度对栓皮栎幼苗蒸腾潜热和叶温的影响
Impacts of radiation, temperature and soil moisture on hidden heat of transpiration and leaf temperature of Quercus variabilis seedlings
摘要
Abstract
[Background] Drought threats plants' survival and in the same time it causes variation of their leaf temperature (TL),which provides people an efficient path to diagnose soil moisture.Many scholars have been using crop leaf-air temperature deficit (LATD) to calculate crop water stress index (CWSI).However,there are few studies on leaf-air temperature of Quercus variabilis,and no works on diagnose of soil moisture.The transpiration (Tr) of Q.variabilis is less than that of crops,and its LATD is larger than agricultural crop,thus the water stress index (WSI) of Q.variabilis should be different to CWSI.The key that uses LATD to evaluate water stress is to analyze the energy factors of leaf temperature.[Methods] Watering the pots then soil moisture decreased through natural evaporation,we controlled soil moisture in 3 levels:light drought,12.5％-14.5％ (W1);moderate drought,9.5％-11.5％ (W2),and severe drought,5.5％-7.5％ (W3).Selecting clear and cloudy days,from 8:00 to 18:00,we measured Tr and TL as well as air temperature (t) and solar radiation (R).We also measured Tr in artificial chamber controlling temperature at 25-43 ℃,at every 2 ℃ interval of treating temperature.According to the ratio of net radiation AR,convection Φc,latent heat of transpiration LE,and leaf area density ρ,heat capacity Cp:AR/ρCp,Φc/ρCp,LE/ρCp,we calculated the contribution of each energy item to TL.[Results] 1) The Tr of W1 was close to of normal soil moisture,the maximum Tr was 2.5 mmol/(m2·s).The Tr of W2 and W3 reduced to be ＜ 1.5 mmol/(m2·s).2) In clear day,Tr positively related to solar radiation,which indicated that solar radiation was main factor of Tr.The slopes of the regression line between Tr and solar radiation were different with different soil moistures,the dryer the soil was,and the greater the slope was.3) In cloudy day,the relation coefficient between Tr and solar radiation decreased clearly,which meant Tr did not decline with short time interval of radiation reducing,once transpiration started in the morning.4) On any case of soil moisture,air temperature was not main factor of Tr.Though in artificial chamber the linear relation of Tr and temperature was clear,Tr was lower than natural clear day.[Conclusions] 1) Light drought did not impact Tr of Q.variabilis.2) When wind speed was zero,solar radiation was main factor of leaf temperature variation.Net radiation accounted for 50％-70％ of energy budget,and provided approximately 7 ℃ of leaf temperature variation.3) The latent heat of Tr and convection heat exchange had an equal effect on energy budget,which accounted for 10％-20％ respectively.Each of two factors caused approximately 1-2 ℃ of leaf temperature variation respectively.关键词
栓皮栎/辐射/温度/土壤水分/蒸腾速率/叶温Key words
Quercus variabilis/radiation/temperature/soil moisture/transpiration/leaf temperature分类
农业科技引用本文复制引用
陈景玲,王佩舒,刘琳奇,王谦,王旭,杨喜田,张劲松..光温条件和土壤湿度对栓皮栎幼苗蒸腾潜热和叶温的影响[J].中国水土保持科学,2017,15(1):62-70,9.基金项目
国家自然科学基金“基于气候空间上限列线的栓皮栎幼苗高温叠加干旱胁迫机制研究”(31370621),“番茄叶片低温胁迫气象指标的气候空间列线研究”(31071321) （31370621）
