湿润区3种杉科植物枝和根木质部的水力功能与解剖结构的关系  

Relationship between the Hydraulic Function and the Anatomical Structure of Branch and Root Xylem in Three Taxodiaceae Species in Humid Area

作　　者：潘天天 李彦 王忠媛[1,2,3] 陆世通 叶琳峰[1] 陈森 谢江波 Pan Tiantian;Li Yan;Wang Zhongyuan;Lu Shitong;Ye Linfeng;Chen Sen;Xie Jiangbo(State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou 311300;State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011;College of Forestry and Biotechnology,Zhejiang A&F University,Hangzhou 311300)

机构地区：[1]浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州311300 [2]荒漠与绿洲生态国家重点实验室中国科学院新疆生态与地理研究所,乌鲁木齐830011 [3]浙江农林大学林业与生物技术学院,杭州311300

出　　处：《林业科学》2020年第12期49-59,共11页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(41730638,31770651,31901280);荒漠与绿洲生态国家重点实验室开放基金项目。

摘　　要：【目的】全球变暖导致干旱强度增大、频率更高。研究湿润区3种杉科植物枝条和根系的水力功能性状和木质部结构性状的差异,以及木质部结构性状与水力功能性状的数量关系,有助于了解湿润区植物的干旱适应机制,为湿润区树木死亡风险在时空上的相对可预测性提供数据支持。【方法】以湿润区池杉、落羽杉和北美红杉为研究对象,测定枝条和根系的导水率和脆弱曲线,制作石蜡切片观察枝条和根系的木质部解剖结构,并计算管胞结构和纹孔结构参数。【结果】3个树种根系的P20、P50、P88(导水率损失20%、50%、88%时所对应的木质部水势,代表枝条和根系栓塞抗性的大小)均小于其枝条;枝、根比导率与P50相关分析的决定系数接近0(R2=0.01,P=0.62)。木质部解剖结构与功能性状的相关分析发现:管胞直径与比导率显著正相关(r=0.82,P=0.001),管胞密度与比导率显著负相关(r=-0.68,P=0.01);纹孔塞面积与P50正相关(r=0.4,P=0.19)。冗余分析表明:管胞直径对比导率有显著影响且解释度达80.1%(P=0.004);纹孔塞面积对P50影响较大且解释度达70.1%(P=0.18)。【结论】杉科3个树种根系的栓塞抗性均比枝条弱。其枝、根木质部导水系统无效率-安全权衡关系,因为决定其输水效率(比导率)的是管胞直径,决定其栓塞抗性(P50)的是纹孔塞面积,即枝、根木质部导水系统不具备效率-安全权衡的基础。3个树种均为低效率低安全性物种。【Objective】Global warming leads to increased intensity and higher frequency of drought.The difference of the hydraulic functions and xylem structure between branches and roots of three Taxodiaceae species in the humid area,as well as the quantitative relationship between the structure and the hydraulic function of xylem,was studied to understand the mechanism of adaptation to drought of plants in the humid area and to provide data support for the relative predictability of tree death risk in humid area in time and space.【Method】Taxodium distichum var.imbricatum,Taxodium distichum and Sequoia sempervirens in humid region were investigated to determine the hydraulic conductivity and vulnerability curve of branches and roots.Paraffin sections were made to observe the xylem anatomical structure,and parameters of the tracheids and pit structural properties were calculated.【Result】P20,P50 and P88(the xylem water potential corresponding to the water loss of 20%,50%and 88%represents the embolism resistance of branches and roots)of roots were all smaller than those of branches.The correlation coefficient between specific conductivity and P50of branches and roots was close to 0(R2=0.01,P=0.62).Correlation analysis of xylem anatomical structure and functional traits showed that:tracheid diameter was positively correlated with specific conductivity(r=0.82,P=0.001),and tracheid density was negatively correlated with specific conductivity(r=-0.68,P=0.01).The pit torus area was positively correlated with P50(r=0.4,P=0.19).Redundancy analysis revealed that:tracheid diameter had a significant effect on the specific conductivity and the interpretation degree was up to 80.1%(P=0.004).The pit torus area had a great influence on P50 and the interpretation degree was up to 70.1%(P=0.18).【Conclusion】The embolism resistance of the roots of three Taxodiaceae species is weaker than that of branches.Tracheid diameter determines the specific conductivity of hydraulic efficiency.The pit torus area determines the embolism resi

关 键 词：池杉 落羽杉 北美红杉 气候变化 湿润区 输水效率 栓塞抗性 

分 类 号：S718.43[农业科学—林学] S718.47