Page 138 - 《广西植物》2025年第1期
P. 138

1 3 4                                  广  西  植  物                                         45 卷
                 Abstract: Vatica guangxiensis is a national first ̄class protected wild plant and the wild plant of extremely small
                 populations. This paper provides a comparative analysis of the photosynthetic physiological characteristics and structural
                 features of V. guangxiensis seedling and adult tree. The Li ̄6400 portable photosynthesis measurement system analyzer and
                 vacuum electron scanning microscope were utilized to investigate the differences between the photosynthetic capacity and
                 leaf structure of leaves at different stages of growth and development. The results were as follows: (1) The right ̄angled
                 hyperbolic modified model was the best model to fit the light response of V. guangxiensis. (2) The maximum net
                 photosynthetic rate ( P  )ꎬ light saturation point ( LSP ) and dark respiration rate ( R ) of adult leaves were
                                  n max                                               d
                 significantly higher than those of seedlingꎬ while the light compensation point (LCP) of adult tree was lower than that of
                 seedling (P<0.05). (3) Chlorophyll aꎬ chlorophyll bꎬ chlorophyll (a+b) and carotenoids in seedlings were significantly
                 lower than those in adult tree (P<0.05). (4) The stomatal long axisꎬ stomatal area and stomatal density of adult tree
                 were significantly higher than those of seedlingꎻ the leaf area and specific leaf weight ( SLW) of adult tree were
                 significantly larger than those of seedling ( P < 0. 05)ꎬ and the specific leaf area ( SLA) was smaller than that of
                 seedling. In summaryꎬ V. guangxiensis exhibits photosynthetic characteristics of a shade ̄loving seedling and a sun ̄loving
                 adult tree. The seedlings have weak light adaptation ability and light energy utilizationꎬ and are unable to photosynthesize
                 sufficiently to meet their growth needs due to excessive shading by adult tree. This is a significant reason why seedlings
                 are unable to grow into large trees. Thereforeꎬ for in situ conservation of V. guangxiensisꎬ human interference can be used
                 to artificially create ‘windows’ in the tree layer to provide sufficient light sources. This is conducive to the growth of
                 V. guangxiensis seedlings into large trees and the renewal of the population. On the other handꎬ for the introductory
                 cultivation of V. guangxiensisꎬ the seedlings need to be appropriately shaded and transplanted to a certain degree of
                 shade. During the initial cultivation processꎬ it is important to provide appropriate shading for seedlings and transplant
                 them to an environment with a suitable level of shade.
                 Key words: Vatica guangxiensisꎬ fitting modelꎬ photosynthetic characteristicsꎬ leaf microstructureꎬ chlorophyll



                广西青梅(Vatica guangxiensis)为落叶乔木ꎬ隶               理的保育措施ꎬ研究人员对广西青梅的群落结构
            属于龙脑香科青梅属ꎬ是我国一级保护野生植物                              (蒋 迎 红 等ꎬ 2016)、 土 壤 理 化 性 质 ( 谭 长 强 等ꎬ
            (肖云学等ꎬ2023)ꎮ 其树干通直圆满ꎬ材色美观ꎬ                         2016)、遗传多样性( Zhu et al.ꎬ 2023) 等方面进行
            木材坚硬ꎬ纹理直ꎬ结构细致ꎬ耐腐性强ꎬ是我国特                            了相关研究ꎬ但并未从光合特性和叶片显微结构
            有的热带珍贵用材树种ꎬ在建筑、桥梁、造船、车厢                            的层面进行研究和报道ꎮ
            以及制造各种高级家具中作为优良用材( 彭玉华                                 光合作用是植物生长和发育的基础ꎬ可根据
            等ꎬ2015)ꎮ 广西青梅具有地域分布狭窄ꎬ种群退                          其特性判断和确定植物最适宜的环境条件和生态
            化和数量稀少等极小种群的特征ꎮ 极小种群野生                             需求(Adamecꎬ 1997)ꎮ 光合特性并非在植物的整
            植物是重要的生物遗传多样性资源ꎬ若不及时保                              个生命周期中都保持不变ꎬ而是随着树龄的变化
            护可能导致它们的生物特征和遗传多样性资源的                              而动态变化(Bondꎬ 2000)ꎮ 研究濒危植物不同时
            消失ꎬ因此保护极小种群植物对于我国的生物多                              期的光合特性差异ꎬ为评估和选择适宜的栖息地
            样性保护具有至关重要的意义( 张则瑾等ꎬ2018)ꎮ                         提供重要参考ꎬ也为濒危植物的保育与精细化栽
            广西青梅主要分布于广西和云南ꎬ生于海拔 500 ~                          培奠定基础ꎮ 对于木本植物ꎬ幼苗和成年植株的
            600 m 的北热带沟谷雨林中的丘陵地带ꎬ广西境内                          光合特性差异较为显著ꎮ 相关研究发现从夹竹桃
            仅在那坡县发现 1 个野生种群ꎮ 广西青梅作为青                           的幼苗与成年植株在光合特性和光保护特性存在
            梅属在广西分布的唯一种类ꎬ对研究我国热带植                              巨大差异ꎬ导致在应对不同季节时呈现出不同生
            物区系有十分重要的意义ꎮ 在那坡县生境中ꎬ广                             理特性( Chondrogiannis et al.ꎬ 2023)ꎻ在热带雨林
            西青梅成年树木生长良好ꎬ然而幼苗自然更新进                              中ꎬ对 17 个物种的幼树与成年植株的叶片特性进
            展困难ꎬ无法正常生长为成树ꎬ种群繁衍与扩展受                             行了对比分析ꎬ发现在所有物种的幼苗与成年植
            到严重桎梏ꎮ 为探究其原因并对广西青梅进行合                             株之间的光合特性与叶片结构均存在显著差异ꎬ
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