Page 16 - 《广西植物》2023年第3期
P. 16

4 1 6                                  广  西  植  物                                         43 卷
              ( 1. College of Life Sciencesꎬ Guangxi Normal Universityꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 2. Guangxi Key Laboratory of Plant Conservation
              and Restoration Ecology in Karst Terrainꎬ Guangxi Institute of Botanyꎬ Guangxi Zhuang Autonomous Region and Chinese Academy of Sciencesꎬ
               Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 3. Nonggang Karst Ecosystem Observation and Research Station of Guangxiꎬ Chongzuo 532499ꎬ Guangxiꎬ
                    Chinaꎻ 4. College of Tourism & Landscape Architecture ꎬ Guilin University of Technologyꎬ Guilin 541006ꎬ Guangxiꎬ China )

                 Abstract: In order to study the adaptive strategies of dominant tree species in a karst seasonal rain forest to
                 heterogeneous habitat conditionsꎬ seven dominant tree species in a virgin forest in Nonggangꎬ Chinaꎬ were taken as the
                 research objects. The leaf micromorphological physiological characteristics of adult individuals of each tree species and
                 the photosynthetic indexes of leaves in the growing season of these trees were measuredꎬ and the response of leaf
                 structure and function of tree species to heterogeneous habitat in karst peak-cluster mountain was discussed. The results
                 were as follows: (1) Along the karst habitat gradient from valley to hilltopꎬ nine leaf micromorphological indexesꎬ such
                 as leaf compactnessꎬ palisade tissue thicknessꎬ cuticle thicknessꎬ and epicuticle thicknessꎬ showed a significant upward
                 trendꎬ while leaf looseness showed a significant downward trend. (2) Along the karst habitat gradient from valley to
                 hilltopꎬ the light compensation pointsꎬ dark respiration rateꎬ and maximum transpiration rates of these leaves all showed
                 a significant upward trend. Howeverꎬ the maximum water use efficiencyꎬ the maximum intercellular CO concentrationꎬ
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                 and the apparent quantum efficiency showed a significant downward trend. ( 3) Leaf compactness was positively
                 correlated with photosynthetic and transpiration ability indexes. Leaf looseness was negatively correlated with these two
                 types of indexes. In conclusionꎬ there is a trade ̄off relationship between photosynthetic efficiency and drought tolerance
                 in leaf functional traits of dominant tree species in the karst seasonal rain forest. Trees distributed in the valley have
                 obvious adaptive characteristics to weak light. Trees distributed on the slope show extensive habitat adaptability. Due to
                 the limitation of strong lightꎬ high temperature and exposed rockꎬ the trees distributed on the hilltop show strong drought
                 adaptability and conservative ecological adaptive strategies.
                 Key words: karstꎬ seasonal rain forestꎬ habitat heterogeneityꎬ leaf micromorphologyꎬ photosynthetic physiological
                 characteristicsꎬ ecological adaptation.



                植物功能性状( functional trait) 是指能够响应               运输通道坍塌和栓塞ꎬ从而威胁叶片水力运输安
            生存环境变化且影响植物生态功能的植物核心属                              全ꎮ 叶片水力安全性状是维持植物叶片水分运输
            性(刘晓娟和马克平ꎬ2015)ꎮ 植物功能性状间存                          安全的功能性状ꎬ涉及植物叶片机械强度和叶脉
            在着普遍的权衡( trade ̄off) 关系ꎬ也被称为生态策                     导管抗坍塌能力等ꎬ与叶片硬度、细胞壁厚度、细
            略( ecological strategy)ꎬ 与 具 体 生 境 条 件 相 适 应       胞排列紧密度、单位面积叶片重量等相关ꎮ 此外ꎬ
            (Wright et al.ꎬ2004ꎻLi et al.ꎬ2021)ꎮ 干旱环境下         叶片气孔性状也与植物生境适应策略密切相关ꎬ
            植物生态策略之一是维持光合作用效率与水力运                              稳定指标包括气孔大小、气孔密度、气孔开度等
            输安全之间的权衡ꎮ 前者与植物的光资源竞争能                             (Sun et al.ꎬ2021)ꎮ 植物可通过关键功能性状差

            力、固碳能力等密切相关ꎬ后者与植物抗旱能力、                             异来应对环境变化ꎬ实现植物光合作用效率和水
            元素耐受能力等密切相关ꎮ 叶片是植物进行光合                             分运输安全之间的权衡( 陈莹婷和许振柱ꎬ2014ꎻ
            作用和水分运输等生理活动的重要器官( 李耀琪                             Li et al.ꎬ 2022)ꎮ 在湿润地区ꎬ植物可能更注重光
            和王志恒ꎬ2021)ꎮ 叶片解剖结构性状与植物光合                          合作用效率ꎬ积累生物量ꎬ从而提高个体竞争能力
            作用效率 等 密 切 相 关 ( Tian et al.ꎬ 2016ꎻ李 冬 林           (孙梅等ꎬ2017ꎻ 张小燕等ꎬ2021)ꎮ 有研究表明ꎬ
            等ꎬ2019)ꎮ 叶片表皮细胞为光进入叶肉提供了窗                          植物的比叶面积、林冠层高度、光合能力、气孔导
            口ꎬ栅栏组织包含大量叶绿体有利于最大化吸收                              水率等相关性状与降雨量呈正相关ꎮ 在干旱地
            光能ꎬ海绵组织具有较大细胞间隙可以改善气体                              区ꎬ植物可能更注重水力安全问题ꎬ增强抗旱型性
            运输ꎮ 叶片水力安全性状与植物耐旱性密切相关                             状ꎬ从 而 维 持 个 体 生 存 能 力 ( 谭 凤 森 等ꎬ 2010ꎻ
            (刘金玉等ꎬ2012ꎻ潘莹萍和陈亚鹏ꎬ 2014)ꎮ 当水                      Zhang et al.ꎬ 2021)ꎮ 耐旱型植物叶片通常具有较
            分供应无法满足植物蒸腾时ꎬ可能引起叶片水分                              大的叶片硬度、角质层厚度、叶肉组织紧密度、栅
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