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枝和叶是组成树冠的两个最主要的结构单元,枝条的结构特征及其与叶性状之间的变化关系决定了植物对光照、空间等资源的利用和适应策略。该研究以小枝茎长度和茎纤细率表征茎结构,以叶面积比(即单位小枝茎干质量的总叶面积)、叶密度(即单位茎长度的叶数量)和叶茎生物量比(即单位小枝茎干质量的总叶干质量)表征展叶效率,以浙江省清凉峰自然保护区25个常绿阔叶物种和60个落叶阔叶物种为对象,探讨小枝茎结构变化对展叶效率的影响。结果显示,展叶效率无论是用叶面积比、叶密度还是用叶茎生物量比表示,常绿和落叶物种小枝的茎长结构性状均与展叶效率呈显著的负相关关系,即随着小枝茎长度和茎纤细率的增加,展叶效率逐渐降低,可能反映了机械安全和光照限制的作用。同时,尽管茎长度-展叶效率的斜率在常绿和落叶物种间无显著差异,并且常绿物种叶密度与小枝茎结构性状之间的关系截距显著大于落叶物种,即常绿物种具有较高的出叶强度。但由于单叶面积和比叶面积显著小于落叶物种,在某一给定的小枝茎长结构下,常绿物种每单位质量的茎生物量投资获得的总叶面积和总叶质量都比落叶物种少,即常绿物种的展叶效率比落叶物种低。这可能反映了常绿物种高消耗慢收益的保守型策略。这些结果表明,小枝茎长结构对展叶效率具有显著的影响,并将随叶习性的不同而改变,与植物对环境的适应策略密切相关。
Branches and leaves are the two most important structural elements that make up the canopy. The structural characteristics of the branches and their relationship with the leaf traits determine the utilization and adaptation strategies of plants to light, space and other resources. In this study, the stem structure was characterized by the ratio of leaf area (the total leaf area per unit stem weight), leaf density (leaf number per unit stem length) and leaf stem biomass ratio Total leaf mass per unit weight of stems and stems) were used to characterize the leaf-spreading efficiency. Twenty-five evergreen broad-leaved species and 60 deciduous broad-leaved species in Qingliangfeng Nature Reserve in Zhejiang Province were used to investigate the effects of stem- Impact. The results showed that no matter leaf area ratio, leaf density or leaf-stem biomass ratio, the leaf-setting efficiency showed that the stem-length structure of the evergreen and deciduous tree branches had a significant negative correlation with leaf-setting efficiency, Increased branchlet stem length and stem slenderness, reduced leaf expansion efficiency, may reflect mechanical safety and light-limiting effects. At the same time, although the slope of stem length-leaf expansion efficiency was not significantly different between evergreen and deciduous species, and the inter-leaf intercept of leaf density of the evergreen species was smaller than that of the deciduous species, ie, evergreen species High leaf strength. However, because of the single leaf area and specific leaf area were significantly smaller than the deciduous species, the total leaf area and total leaf mass per unit mass of stem biomass invested by the evergreen species under a given twig-stem length structure were lower than those of the deciduous species Less, that is, evergreen species exhibit lower leaf-setting efficiency than the deciduous species. This may reflect the conservative strategy of slowing down the consumption of evergreen species. These results indicate that the branchlet length structure has a significant effect on the leaf expansion efficiency and will vary with leaf habitability and is closely related to the plant adaptation strategy to the environment.