Page 167 - 《广西植物》2022年第3期
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3 期       孙鹏等: 南亚热带常绿阔叶林冠层和林下层优势种叶功能性状响应异质生境的差异                                            5 1 1

            Differences in leaf functional trait responses to

       heterogeneous habitats between dominant canopy and

              understory tree species in a south subtropical

                           evergreen broad ̄leaved forest


                              1ꎬ3ꎬ4           2              1ꎬ3ꎬ4             1ꎬ3ꎬ4∗
                   SUN Peng      ꎬ WEI Xiao ꎬ YE Wanhui          ꎬ SHEN Hao
   ( 1. Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystemsꎬ South China Botanical Gardenꎬ Chinese Academy of Sciencesꎬ
       Guangzhou 510650ꎬ Chinaꎻ 2. Guangxi Institute of Botanyꎬ Guangxi Zhuang Autonomous Region and Chinese Academy of Sciencesꎬ Guilin
          541006ꎬ Guangxiꎬ Chinaꎻ 3. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)ꎬ Guangzhou 511458ꎬ
              Chinaꎻ 4. School of Resources and Environmentꎬ University of Chinese Academy of Sciencesꎬ Beijing 100049ꎬ China )
       Abstract: Plant species can adapt to heterogeneous habitats through variations in functional traits. For the plants with
       different growth formsꎬ how to adjust their phenotypes to adapt to the environment has been one of the core topics in
       ecology. To clarify the response mechanisms of plant species with different growth forms to heterogeneous habitats in
       south subtropical forestsꎬ we measured a total of eight functional traits involving four structural traits (leaf thicknessꎬ leaf
       length/ width ratioꎬ leaf dry matter content and specific leaf area) and four stoichiometric traits (leaf nitrogen contentꎬ
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       leaf phosphorus contentꎬ d C and d N) of five dominant trees (2 canopy species and 3 understory species) and their
       diameter at breast heightꎬ in 27 quadrats (20 m × 20 m) at different elevations and convexity along three mountain
                          2
       ridges within the 20 hm south subtropical evergreen broad ̄leaved forest plot at Dinghu Mountain in Guangdong
       Province. We analyzed and compared the differences in responses of the canopy and understory species to different
       elevations and convexity in terms of functional traits. The results were as follows: (1) There existed some leaf functional
       traits in each tree species that were significantly correlated with altitudeꎬ but for convexityꎬ only the leaf area of
       Cryptocarya chinensis was positively correlated with convexity and the leaf nitrogen content of Blastus cochinchinensis was
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       negatively correlated with convexity. (2) Specific leaf areaꎬ leaf thickness and d N were generally more responsive to
       elevationꎬ while leaf length/ width ratio and leaf dry matter content were less responsive. (3) There were significant
       differences in specific leaf areaꎬ leaf dry matter content and leaf nitrogen content between canopy and understory tree
       species in heterogeneous habitats. Compared with canopy tree speciesꎬ understory tree species had lower leaf thicknessꎬ
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       leaf dry matter content and d C. Moreoverꎬ canopy and understory species responded to elevation and convexity to
       different extentsꎬ with understory species having more functional traits with significant differences in different types of
       habitats. The results indicate that the degree of response to the environment varied greatly between plants with different
       growth formsꎬ i.e.ꎬ the dominant understory tree species had greater plasticity in the heterogeneous habitats than the
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       dominant canopy species in the forest plot. In additionꎬ specific leaf areaꎬ leaf thickness and d N are important and
       effective traits indicating plant adaptation and responses to the environment in the south subtropical evergreen broad ̄
       leaved forest.
       Key words: functional traitsꎬ canopy speciesꎬ understory speciesꎬ elevation gradientꎬ topographical factors

       全球多数生态系统均在经历不同程度的扰                            异还未得出一致性规律ꎬ植物在气候及环境改变
   动ꎬ导致植物种群动态和分布区域发生持续改变                             下的适应机制仍然有待进一步探索( Anderson &
   (Parmesanꎬ 2006ꎻZhou et al.ꎬ 2013)ꎮ 由于功能性         Gezonꎬ 2015)ꎮ 一种典型的研究方式是利用山地
   状能够反映物种对环境的适应过程ꎬ从不同角度                             的异质生境探索植物性状对不同类型生境的响应
   刻画物种生理和生态的信息ꎬ因此理解植物-环境                            和适应ꎮ 海拔梯度的变化会影响该区域的水、气、
   关系的生理生态机制需要结合植物功能性状进行                             热和土壤等多个环境因子ꎬ温度、气压以及二氧化

   研究(Chapinꎬ 2003ꎻWright et al.ꎬ 2004ꎻMcGill et     碳浓 度 等 均 会 随 海 拔 梯 度 升 高 而 下 降 ( Kao &
   al.ꎬ 2006)ꎮ 然而ꎬ功能性状的可塑性以及时空变                      Changꎬ 2001)ꎬ而海拔和凹凸度升高会导致光照强
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