Defoliation modality significantly affected leaf traits and carbon allocation especially in the early recovery period of two Leguminosae woody species. Robinia pseudoacaciaL. recovered more quickly following defoliation thanAmorpha fruticosaL. Defoliation resulting from anthropogenic disturbance, insects, and grazing animals affects plant growth and vegetation dynamics. Robinia pseudoacacia L. and Amorpha fruticosa L. with different susceptibility to biotic attack are commonly used for vegetation restoration in North China. However, plant responses to defoliation were not fully understood in the two Leguminosae woody species. We selected R. pseudoacacia and A. fruticosa to determine the effects of defoliation on individual plant growth, leaf traits, and carbohydrate allocation and compared the two species in terms of recovery strategies following defoliation for vegetation restoration. In a greenhouse experiment, A. fruticosa and R. pseudoacacia seedlings were subjected to three defoliation treatments: defoliation of the top down (TD) or bottom up (BU) 50% of the crown, and a control without defoliation (CK). The physiological and growth traits of seedlings were determined at 1, 3, 14, 30, and 60 days following defoliation. Plant growth in both species recovered after 2 months whatever defoliation modalities. Carbon allocation in both species was greatly affected by defoliation modalities during the early recovery period but had been fully recovered after 60 days of treatment. In the end of the experiment, defoliation modalities still had obvious impacts on leaf characteristics, especially in chlorophyll concentration and specific leaf area. R. pseudoacacia exhibited more evident compensatory mechanisms than A. fruticosa following defoliation. Defoliation modality treatments significantly affect most leaf traits and carbon allocation, especially in the early recovery period of both species. Considering the faster recovery ability of R. pseudoacacia than A. fruticosa after defoliation, R. pseudoacacia seedlings may be more suitable for vegetation restoration in North China.

中文翻译：

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落叶方式对金缕梅和刺槐幼苗植物生长、叶片性状和碳水化合物分配的影响

落叶方式显着影响叶片性状和碳分配，特别是在两种豆科木本植物的早期恢复期。刺槐 落叶后恢复得比 Amorpha fruticosaL 更快。人为干扰、昆虫和放牧动物造成的落叶影响植物生长和植被动态。对生物侵袭的敏感性不同的刺槐和紫荆是华北地区植被恢复的常用材料。然而，在两种豆科木本物种中，植物对落叶的反应尚不完全清楚。我们选择了 R. pseudoacacia 和 A. fruticosa 来确定落叶对个体植物生长、叶片性状、和碳水化合物分配，并在植被恢复落叶后的恢复策略方面比较了这两个物种。在温室实验中，对 A. fruticosa 和 R. pseudoacacia 幼苗进行了三种脱叶处理：自上而下 (TD) 或自下而上 (BU) 50% 的树冠脱叶，以及不脱叶的对照 (CK)。在落叶后1、3、14、30和60天测定幼苗的生理和生长性状。无论采用何种落叶方式，这两个物种的植物生长均在 2 个月后恢复。两种物种的碳分配在早期恢复期间受到落叶方式的极大影响，但在处理 60 天后已完全恢复。在实验结束时，落叶方式对叶片特性仍有明显影响，尤其是叶绿素浓度和比叶面积。R. pseudoacacia 在落叶后表现出比 A. fruticosa 更明显的补偿机制。落叶方式处理显着影响大多数叶片性状和碳分配，特别是在两个物种的早期恢复期。考虑到刺槐在落叶后的恢复能力比刺槐快，刺槐幼苗可能更适合华北地区的植被恢复。