干旱胁迫及复水对油松渗透调节物质及水力功能的影响  

Effects of drought and re-irrigation on osmotic regulator and hydraulic function of Pinus tabuliformis

作　　者：冒吉荣 曾岩 徐馨妤 梁静[1] 刘莹[1,3] MAO Jirong;ZENG Yan;XU Xinyu;LIANG Jing;LIU Ying(College of Soil and Water Conservation Science and Engineering,Northwest A&F University,Yangling 712100,Shaanxi,China;College of Life Sciences,Yan'an University,Yan'an 716000,Shaanxi,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling 712100,Shaanxi,China)

机构地区：[1]西北农林科技大学水土保持科学与工程学院,陕西杨凌712100 [2]延安大学生命科学学院,陕西延安716000 [3]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《应用生态学报》2024年第11期2959-2965,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金重点项目(42130717);青年基金项目(42007062)资助。

摘　　要：近年来我国半干旱地区极端干旱事件发生频率增加,探究植物对干旱和复水的响应机制对该区人工林幼苗选育具有重要意义。本研究以2年生油松幼苗为对象,设置不减雨(对照)、减雨25%(轻度胁迫)、减雨50%(中度胁迫)、减雨75%(重度胁迫)4个处理进行长期干旱胁迫(20个月),然后开展极端干旱处理(连续80 d减雨100%),并在极端干旱第10、40、70和80天进行为期10 d的复水处理,探究上述过程中油松新枝导水率、导水率损失百分比和渗透调节物质含量间的相关关系及对干旱的响应。结果表明:长期干旱胁迫时,轻度胁迫下油松新枝在导水率损失50%时对应的水势阈值为-2.04 MPa,显著低于其他处理;极端干旱80 d后,油松新枝脯氨酸含量相对于初始值显著增加了19.9%~226.0%。冗余分析表明,脯氨酸对水力功能的解释率为40.4%,是极端干旱时期的主要渗透调节物质。在复水过程中,可溶性糖对水力功能的解释率为29.4%,是该阶段的主要渗透调节物质。干旱及复水过程中油松水力功能差异的原因不同,轻度胁迫提升了油松的抗栓塞能力,极端干旱时油松新枝通过积累脯氨酸以维持正常的水分运输,复水时可溶性糖与导水率呈显著正相关,利于修复栓塞并增强水力功能的恢复能力。Understanding how plants respond to drought and re-irrigation is crucial for the successful breeding of seedlings in artificial forests in semi-arid regions of China,as the frequency of high-intensity drought events has significantly increased in these areas.We conducted an experiment with four drought stress treatments,including no reduction in rainfall(control),25%reduction in rainfall(mild stress),50%reduction in rainfall(moderate stress),and 75%reduction in rainfall(severe stress).We subjected two-year-old Pinus tabuliformis seedlings to a long-term drought stress period of 20 months,followed by a high-intensity drought treatment(continuous 80 days with 100%rainfall reduction).Additionally,we administered re-irrigation treatments lasting 10 days on days 10,40,70,and 80 of the high-intensity drought period.We aimed to investigate the relationships among hydraulic conductivity,percentage loss of hydraulic conductivity,and the content of osmotic adjustment substances in new branches of P.tabuliformis,as well as their responses to drought.The results showed that under long-term drought stress,the water potential threshold at which hydraulic conductivity loss reached 50%for new branches under mild stress was-2.04 MPa,which was significantly lower than that of the other treatments.After 80 days of high-intensity drought,the proline content in new branches increased significantly by 19.9%to 226.0%compared to the initial value.Redundancy analysis showed that proline explained 40.4%of the variability in hydraulic function and was the primary osmotic adjustment substance during high-intensity drought.During re-irrigation,soluble sugars explained 29.4%of the variability in hydraulic function and were the main osmotic adjustment substances in this stage.Different factors accounted for the differences in hydraulic function of P.tabuliformis during drought and re-irrigation.Mild stress enhanced the embolism resistance under the long-term drought.New branches of P.tabuliformis maintained normal water transport by accumulati

关 键 词：长期干旱 极端干旱 复水 渗透调节 水力功能 

分 类 号：S791.254[农业科学—林木遗传育种]