白杨杂交子代栓塞脆弱性分割及与生长的关系  

Hydraulic Vulnerability Segmentation and Its Correlation with Growth in Hybrid Poplar

作　　者：韩璐 赵涵[1] 王薇[1] 刘文辉 姜在民[2] 蔡靖 Han Lu;Zhao Han;Wang Wei;Liu Wenhui;Jiang Zaimin;Cai Jing(College of Forestry,Northwest A&F University ,Yangling 712100;College of Life Sciences,Northwest A&F University, Yangling 712100;Qinling National Forest Ecosystem Research Station, Yangling 712100)

机构地区：[1]西北农林科技大学林学院,杨凌712100 [2]西北农林科技大学生命科学学院,杨凌712100 [3]陕西秦岭森林生态系统国家野外科学观测研究站,杨凌712100

出　　处：《林业科学》2023年第3期94-103,共10页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(31570588,32271578)。

摘　　要：【目的】研究不同生长速率白杨杂交子代有无脆弱性分割、脆弱性分割差异及与生长的关系,为脆弱性分割假说检验提供试验证据,也为杨树耐旱性评价及生长策略提供支撑。【方法】以快速(K)、中速(Z)、慢速(M)3种生长速率类型的4年生白杨杂交子代为研究材料,每种子代类型选3~6株单株,测定其地上生物量(AGB)、中午叶水势(Ψ_(middy))以及根、枝、叶的栓塞脆弱性(P_(50)),计算叶片与枝条的水力安全边际(HSM),测定木质部导管水力结构指标导管直径(D_V)、导管水力直径(D_(H))、导管密度(V_(D))、导管腔占比(F_(L))和导管抗垮塌能力(t/b)^(2)。【结果】1)地上生物量中K>Z>M,且M显著小于K和Z。2)枝条的P_(50)中M显著低于K和Z,而叶片和根段的P_(50)在K、Z、M间无显著性差异;不同器官间,枝条的P_(50)低于叶片和根段。3)在导管水力结构上,M枝条的导管直径、导管水力直径、b值显著低于K和Z,(t/b)^(2)显著高于K和Z,M叶片的导管直径与Z相近,但显著低于K;M根段的导管密度显著大于K和Z,其余指标无显著差异。不同器官间,导管直径沿水力路径由根到叶片逐渐缩小,根段导管直径最大为叶片的5.12倍,而导管密度由根到枝条逐渐增大,根段的导管密度仅是枝条的1/4。4) 3种子代类型均存在脆弱性分割现象,其中M的分割程度最大,略高于K,是Z的2倍;在叶片水力安全边际上,Z的更宽,K与M的较窄甚至为负,而枝条的水力安全边际在三者之间相差较小。【结论】不同生长速率的3种杂交杨子代均存在栓塞脆弱性分割,其中生长最慢的M的分割程度最大。不同器官的栓塞脆弱性差异可通过导管直径、(t/b)^(2)等导管水力结构得以反映。枝条木质部导管水力结构的差异可能是造成K、Z、M脆弱性分割程度不同的主要原因。与K和Z相比,生长速率最慢的M的枝条栓塞抗性更高、脆弱性分割程度更大,二者可能共同作【Objective】Hydraulic vulnerability segmentation is one of important drought resistance mechanisms of plants.The study on the differences of vulnerability segmentation among hybrid poplar individuals with different growth rates and the relationship between vulnerability segmentation and growth can not only provide experimental evidence for testing vulnerability segmentation hypothesis,but also provide theoretical basis and practical guidance for evaluating drought tolerance and growth strategy of the poplar under the background of frequent drought.【Method】Three clones(K,Z,M)of 4-year-old offsprings of hybrid poplar[I-101(Populus alba)×84K(P.alba×P.glandulosa)]with different growth rates were selected as the research materials,and 3–6 plants were selected from each clone.Aboveground biomass(AGB)and the midday leaf water potential(Ψ_(middy))were measured,and the vulnerability curves of roots,branches and leaves were constructed(P_(50)).The hydraulic safety margin(HSM)of leaves and branches were calculated,and the anatomical traits of xylem vessels were measured,including the vessel diameter(D_(V)),hydraulic weighted vessel diameter(D_(H)),vessel density(V_(D)),vessel lumen ratio(F_(L))and(t/b)^(2).【Result】1)The clone K had the highest AGB,followed by clone Z,and both of them were significantly higher than clone M.2)The P_(50) of branches of M was significantly lower than that of K and Z,while the P_(50) of leaves and root segments had no significant difference among the three clones.Among different organs,the P_(50) of branches was lower than that of leaves and roots.3)In terms of vessel anatomical traits,the DH,DV and b of branches of M were significantly lower than those of K and Z,and the(t/b)^(2) was significantly higher than that of K and Z.The DV of leaves of M was similar to Z,but significantly lower than that of K.The VD of root segment of M was significantly higher than that of K and Z,and other indexes showed no significant difference.Among different organs,the DV gradually decreased along

关 键 词：杨树 栓塞脆弱性分割 木质部水力结构 生长速率 

分 类 号：S718.43[农业科学—林学]