Page 142 - 《广西植物》2026年第1期
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1 3 8                                  广  西  植  物                                         46 卷
                              2. Institute of Tropical Agriculture and Forestryꎬ Hainan Universityꎬ Haikou 570228ꎬ China )

                 Abstract: Hopea hainanensis is a national first ̄class protected plant species in China. Functional traits of branches and
                 leaves and their intraspecific variation are widely used to analyze plants’ environmental adaptability. Understanding its
                 adaptive strategies across different growth stages is critical for formulating effective ex situ conservation measures.
                 Howeverꎬ research on the functional traits of H. hainanensis remains scarce. To investigate the adaptability of branch and
                 leaf structures at different diameter classes in H. hainanensisꎬ in this studyꎬ we selected individuals planted at different
                 time in the Xinglong Tropical Gardenꎬ Hainanꎬ Chinaꎬ with diameter at breast height (DBH ranged from 1 cm to 17
                 cm)ꎬ and measured canopy branch xylem structural traits ( vessel lumen proportionꎬ vessel wall proportionꎬ axial
                 parenchyma proportionꎬ ray parenchyma proportionꎬ fiber proportionꎬ vessel densityꎬ vessel wall reinforcement
                 coefficient)ꎬ hydraulic traits (hydraulic vessel diameterꎬ theoretical hydraulic conductivity)ꎬ leaf morphological and
                 anatomical traits ( thickness of leaf tissues and specific leaf area)ꎬ and mechanical resistance. Pearson correlation
                 analysis and principal component analysis were used to explore the correlation between traits and diameter classesꎬ as
                 well as among branch and leaf traits. The results were as follows: (1) As the DBH increasedꎬ the proportion of vessel
                 lumen and wallꎬ and parenchyma cell per branch xylem cross ̄section areaꎬ hydraulically ̄weighted vessel diameterꎬ and
                 theoretical hydraulic conductivity significantly increasedꎬ while the fiber tissue proportionꎬ vessel densityꎬ and vessel
                 wall reinforcement coefficient significantly decreased. (2) The thickness of individual leaf tissues (epidermisꎬ cuticleꎬ
                 and mesophyll) and the mechanical resistance of the leaf blade increased significantly with DBH. (3) At the individual
                 levelꎬ the branch hydraulic efficiency was positively correlated with leaf tissue thickness. In conclusionꎬ large diameter
                 individuals of H. hainanensis enhance their xylem hydraulic capacity by adjusting branch xylem structureꎬ while
                 increacing leaf thickness to reduce transpirational water loss. The structural coordination between branch and leaf could
                 maintain water balance. The results reveal the adaptive adjustment of branch and leaf structure with increasing DBH
                 (corresponding to increasing transpirational water demandꎬ light intensityꎬ and vapor pressure deficit ) in H.
                 hainanensisꎬ thus offering valuable implications for the species’ conservation and cultivation.
                 Key words: xylem tissueꎬ water transportꎬ leaf thicknessꎬ mechanical resistanceꎬ intraspecific variation




                植物的功能性状是植物在长期对环境的适应                            状及其相关关系能更全面地了解植物的适应策略
            进化过程中形成的核心属性ꎬ能够影响植物对环                              (Alon et al.ꎬ 2024)ꎮ
            境的耐受度ꎬ进而决定植物的生存、繁殖与分布                                  前期观点认为植物性状的种间 变 异 程 度 显
            (Díaz & Cabidoꎬ 2001ꎻ Bakker et al.ꎬ 2011)ꎮ 叶      著超过种内变异( Díaz et al.ꎬ 2004) ꎻ关于植物枝
            片经济学谱系表征植物以资源投资-收益权衡为                              叶功能性状的研究集中在种间变异上ꎬ主要用于
            基础的一类功能性状ꎬ比叶面积较大的植物具有                              比较不 同 物 种 或 功 能 群 的 生 态 策 略 ( Standen &
            较高的光合速率(Pan et al.ꎬ 2020)ꎬ但机械抗性较                   Baltzerꎬ 2023ꎻ Ferrara et al.ꎬ 2024 ) ꎮ 然 而ꎬ
            低ꎬ易遭受非生物因素(如强风)和生物因素( 如虫                           Albert 等(2010) 研究表明ꎬ植物功能性状变异中
            食)造成的机械损伤(Enrico et al.ꎬ 2016ꎻ 韦伊等ꎬ                约有 30%源自种内差异ꎮ 在分析欧洲干燥草原 5
            2022)ꎮ 木材经济学谱系表明ꎬ拥有较高木质部导                          种共生植物的 14 种功能性状时ꎬ有 9 种性状的
            水率(导管密度和管腔直径较大) 的树种能够更高                            种内变异性超过了种间变异水平ꎬ表明种内变异
            效地进行水分传输ꎬ从而支持更快的生长速度及                              是塑造 植 物 群 落 结 构 和 动 态 的 关 键 因 素 之 一
            更高的生产力( Eller et al.ꎬ 2017)ꎬ但会降低木质                 ( Tautenhahn et al.ꎬ 2019) ꎮ 近 年 来 的 研 究 还 广
            部栓塞抗性、薄壁组织的储存以及纤维组织的支                              泛揭示了植物枝叶性状间同样具有显著的种内

            撑功能 ( 倪 鸣 源 等ꎬ2021ꎻ Aguirre et al.ꎬ 2024)ꎮ         变异性ꎬ并在植物响应环境变化方面发挥关键作
            植物不同器官之间也呈现协同或权衡关系ꎬ能够                              用( Xu et al.ꎬ 2020ꎻ Zhao et al.ꎬ 2022) ꎮ 例如ꎬ
            优化资源利用效率ꎬ减少环境变化带来的不利影                              通过分析胡杨( Populus euphratica) 不同径级个体
            响(Westoby et al.ꎬ 2002)ꎮ 因此ꎬ综合分析枝叶性                的枝叶形态数量性状发现ꎬ随着径级增大ꎬ叶片
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