温带地区不同水分调节行为树种的木质部栓塞特性及其光合响应  

Characteristics of xylem embolism and photosynthetic response of tree species with different water regulation behaviors in temperate regions

作　　者：唐华欣 杨永清[1] 蒋海港 刘伟 李杰林 姚银安[2] TANG Huaxin;YANG Yongqing;JIANG Haigang;LIU Wei;LI Jielin;YAO Yinan(College of Life Science,Chongqing Normal University,Chongqing 401331,China;College of Life Science&Engineering,Southwest University of Science and Technology,Mianyang 621000,China)

机构地区：[1]重庆师范大学生命科学学院,重庆401331 [2]西南科技大学生命科学与工程学院,绵阳621000

出　　处：《生物学杂志》2022年第4期61-66,共6页Journal of Biology

基　　金：国家自然科学基金面上项目(31770644);国际(地区)合作研究项目(31850410483)。

摘　　要：以7种温带树种为例,采用自然干燥法建立枝条木质部导水率损失值(PLC)与枝条水势的栓塞脆弱性(VC)曲线;并在控制条件下对树种进行盆栽试验,进行土壤持续干旱处理,在对照、50%PLC和80%PLC水势的中度和重度干旱条件下分析植物气体交换和光化学参数。结果表明:7种物种木质部栓塞脆弱性从大到小依次为麻栎、辽东冷杉、欧美黑杨、云杉、北美红杉、鸡爪槭、赤皮青冈。欧美黑杨的栓塞脆弱性曲线为“S”型,其余6种为“R”型。在中度及重度干旱胁迫时,植株光合能力和PSII反应中心活性均显著下降。赤皮青冈、北美红杉、欧美黑杨、麻栎为等水调节行为树种,云杉为中间型树种,鸡爪槭、辽东冷杉为非等水树种。研究表明树木的水分调节方式与其抗栓塞能力和抗旱性关系不大。基于PLC设计抗旱性试验能够清楚反映种间水分调节和抗旱性差异,理解树木适应中度以上干旱强度的生存机制。种间分析表明:胞间CO_(2)浓度(而非常用的Fv′/Fm′)对木质部栓塞程度具有一致的响应,可作为干旱下栓塞预测指标。In this study,seven typical temperate tree species were used as examples to establish vulnerability curve(VC)of water potential and xylem loss(PLC)by natural drying method.Continuous soil drought treatment was carried out on the tree species under controlled conditions to analyze plant gas exchange and photochemical parameters at the point of control,moderate drought(50%PLC water potential)and severe drought conditions(80%PLC water potential).The sequence of vulnerability to xylem embolism of 7 species was followed by Quercus acutissima,Abies holophylla Maxim.,Populusnigra,Picea asperata Mast.,Sequoia sempervirens,Acer palmatum and Cyclobalanopsis glauca.The embolization VC curve of Populusnigra was“S”type,while the other 6 species’were“R”type.Under moderate and severe drought stress,photosynthetic rate and PSII activity were decreased significantly.Cyclobalanopsis glauca,Sequoia sempervirens,Populusnigra and Quercus acutissima were tested as isohydric species,Picea asperata Mast.was tested as intermediate species,Acer palmatum and Abies holophylla Maxim.were tested as anisohydric species.Result showed that the water regulation pattern of these different trees had little relationship with embolism resistance and drought resistance.Drought resistance experiments based on PLC could clearly reflect the interspecific differences in water regulation and drought tolerance,and help us clarify the survival mechanism of trees to moderate or higher drought stress.Interspecific analysis showed that intercellular CO_(2) concentration(not Fv′/Fm′)had a consistent response to the degree of xylem embolization,which could be used as a predictor of embolization under drought condition.

关 键 词：脆弱性曲线 木质部栓塞 等水物种 非等水物种 叶绿素a荧光 

分 类 号：Q945.11[生物学—植物学]