摘要
在全球气候变化背景下,干旱诱导木质部栓塞被认为是驱动树木死亡的主要因素。因此,分析木质部栓塞抗性(用导水率损失50%的水势(P_(50))表示)的内在解剖决定因素对于理解其结构与功能间的机制具有重要意义,为气候变化背景下植被恢复树种选择提供理论依据。该研究测定广西弄岗喀斯特森林内12个主要常绿树种的木质部导管直径、导管组指数、组分占比、纹孔形态和纹孔膜超微结构,同时结合木质部储水特征(如木材密度和饱和含水量),综合分析干旱诱导木质部栓塞抗性与其解剖结构以及储水特征之间的关系。结果显示:(1)P_(50)与导管直径、密度、导管组指数以及组分占比间的相关性均不显著;(2)P_(50)形态特征以及纹孔膜厚度和纹孔腔深度等特征间的相关性均不显著;(3)P_(50)与木材密度显著负相关,与饱和含水量边缘显著正相关,即木材密度较大、饱和含水量较低的树种表现出较强的栓塞抗性。研究结果表明,运用单一的解剖结构来评估栓塞抗性是不全面的;此外,木质部水分存储能力与栓塞抗性之间的权衡关系对于深入理解喀斯特植物耐旱性的内在结构机制以及多元化的水分利用策略具有重要的生态学意义。
Aims In the context of global climate change,drought-induced xylem embolism is considered as the main factor driving tree death.Therefore,analyzing the intrinsic anatomical determinants of xylem embolism resistance(water potential at 50%loss of xylem conductivity,P_(50))is of great significance for understanding the mechanism between its structure and function,and provides a theoretical basis for the selection of tree species for vegetation restoration in the context of climate change.Methods We measured the xylem vessel diameter,vessel grouping index,fractions of xylem tissues,pit morphology,pit membrane ultrastructure and water storage capacity(such as wood density and saturated water content),and explored the relationships between xylem embolism resistance and their anatomical structure and structural characteristics of 12 main evergreen tree species in Nonggang karst forest of Guangxi.Important findings We found that:(1)P_(50)had no significant correlation with vessel diameter,density,vessel grouping index and fraction of xylem tissues;(2)The correlations between P_(50)and pit morphology,thickness of pit membrane and depth of pit chamber were not significant;(3)P_(50)was negatively correlated with wood density and marginally positively correlated with saturated water content.Tree species with high wood density and low saturated water content had strong embolism resistance.The results indicated that using a single anatomical structure trait could not give out comprehensive evaluation on drought-induced embolic resistance.In addition,there was a trade-off between xylem water capacity and embolism resistance.This result was of great ecological significance for deeply understanding the internal structural mechanism of drought tolerance and diversified water use strategies of karst plants.
作者
马琳
巢林
何雨莎
李忠国
王爱华
刘晟源
胡宝清
刘艳艳
MA Lin;CHAO Lin;HE Yu-Sha;LI Zhong-Guo;WANG Ai-Hua;LIU Sheng-Yuan;HU Bao-Qing;LIU Yan-Yan(Institute of Geography and Oceanography,Nanning Normal University,Key Laboratory of Environment Change and Resource Use in Beibu Gulf(Ministry of Education),Guangxi Key Laboratory of Earth Surface Process and Intelligent Simulation,Nanning 530001,China;Experimental Center of Tropical Forestry,Chinese Academy of Forestry,Guangxi Youyiguan Forest Ecosystem Research Station,Pingxiang,Guangxi 532600,China;Administration Ceter of Guangxi Nonggang National Nature Reserve,Longzhou,Guangxi 532400,China.)
出处
《植物生态学报》
CAS
CSCD
北大核心
2024年第7期888-902,共15页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(31800333和32160252)
中央引导地方科技发展基金(桂科AD19245133和桂科AD20238078)
中国博士后科学基金(2019M663870XB)
广西自然科学基金(2018GXNSFBA138009和2018GXNSFAA281277)
南宁师范大学科研启动项目(602021239137)
北部湾环境演变与资源利用教育部重点实验室(南宁师范大学)开发或系统基金项目(GTEU-KLOP-X1709)资助。