利用植物气体交换参数确定萎蔫系数的方法  

Determination of Wilting Coefficient by Using the Plant Gas Exchange Parameters

作　　者：周谷 李秧秧[1,2] 樊军[1,2] ZHOU Gu;LI Yangyang;FAN Jun(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《土壤学报》2023年第3期776-786,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41977016)资助。

摘　　要：萎蔫系数是确定土壤有效水范围、储量和对植物有效性的关键因子,但现有的基于植物形态变化测定的萎蔫系数存在生理意义不明确及难以在田间原位测定的缺陷。为此,本研究利用自然干旱下的盆栽试验,测定了2种土壤质地(黄土高原区黄绵土和南方丘陵区红壤)下4种植物(大豆Glycine max L.、向日葵Helianthus annuus L.、苜蓿Medicago sativa L.、羊草Leymus chinensis(Trin.)Tzvel)幼苗的萎蔫系数及叶片气体交换参数对土壤水分含量变化的动态响应过程,探讨了基于植物气体交换参数确定的土壤水分下限阈值与萎蔫系数的关系。结果表明:(1)土壤质地和植物抗旱性显著影响萎蔫系数,且影响在永久萎蔫时对应的土壤水势。4种植物在黄绵土下的萎蔫系数分别为0.083 cm^(3)·cm^(-3)(向日葵)>0.081 cm^(3)·cm^(-3)(大豆)>0.072 cm^(3)·cm^(-3)(羊草)>0.060 cm^(3)·cm^(-3)(苜蓿),在红壤下的萎蔫系数表现为0.188 cm^(3)·cm^(-3)(向日葵)>0.180 cm^(3)·cm^(-3)(大豆)>0.174 cm^(3)·cm^(-3)(羊草)>0.172 cm^(3)·cm^(-3)(苜蓿)。4种植物在红壤上的萎蔫系数均大于黄绵土,且植物抗旱性越强,其萎蔫系数越低。(2)利用三次函数模拟气孔导度变化确定的土壤水分下限阈值与萎蔫系数存在高度一致性。因此,萎蔫系数可基于植物气体交换参数进行间接估算。【Objective】The wilt coefficient is a key factor in determining the effective soil water range,reserves and availability to plants.However,the existing wilting coefficient based on plant morphological changes has the disadvantages of unclear physiological significance and is difficult to determine in the field.【Method】To this end,in this study a pot experiment under dry-down drought was used to determine the wilting coefficients of 4 plant seedlings(Glycine max L.,Helianthus annuus L.,Medicago sativa L.,and Leymus chinensis(Trin.)Tzvel)grown under two soil textures(loessial soil in the Loess Plateau and red soil in the southern hilly area).We evaluated the dynamic response of leaf gas exchange parameters to changes in soil moisture content,the relationship between the lower threshold of soil moisture determined based on plant gas exchange parameters,and the wilting coefficient.【Result】The results showed that:(1)Soil texture and plant drought resistance significantly affected the wilting coefficient of plants and the corresponding soil water potential at permanent wilting.The wilting coefficients of all four plants were greater on the red soil than on loessial soil.Importantly,the stronger the drought resistance of a plant,the lower its wilting coefficient.The wilting coefficients of the four plants under loessial soil were 0.083 cm^(3)∙cm^(-3)(Helianthus annuus L.)>0.081 cm^(3)∙cm^(-3)(Glycine max L.)>0.072 cm^(3)∙cm^(-3)(Leymus chinensis(Trin.)Tzvel)>0.060 cm^(3)∙cm^(-3)(Medicago sativa L.).Also,the wilting coefficients under red soil were 0.188 cm^(3)∙cm^(-3)(Helianthus annuus L.)>0.180 cm^(3)∙cm^(-3)(Glycine max L.)>0.174 cm^(3)∙cm^(-3)(Leymus chinensis(Trin.)Tzvel)>0.172 cm^(3)∙cm^(-3)(Medicago sativa L.).(2)The soil moisture lower threshold determined by using a cubic function to simulate the change of stomatal conductance was highly consistent with the measured wilting coefficient.【Conclusion】Thus,the wilting coefficient could be estimated indirectly based on plant gas exchang

关 键 词：萎蔫系数 气体交换参数 土壤水分 动态响应 土壤质地 植物抗旱性 

分 类 号：S728.2[农业科学—林木遗传育种]