Jiao Jiejie, Wu Chuping, Sun Honggang, Yao Liangjing
Zhejiang Academy of Forestry, Hangzhou 310023, China.
Zhejiang Hangzhou Urban Forest Ecosystem Research Station, Hangzhou 310023, China.
Plants (Basel). 2025 Aug 27;14(17):2675. doi: 10.3390/plants14172675.
Intra-specific variation in functional traits and their inter-relationships reflect how plants allocate resources, adapt, and evolve in response to environmental changes. This study investigated eight functional traits-leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), chlorophyll content (CHL), leaf nitrogen content (LNC), leaf phosphorus content (LPC), twig tissue density (TTD), and wood density (WD)-in plantations of three stand ages (15, 30, and 50 years), using a space-for-time substitution approach. We examined differences in trait values, intra-specific variation, and trait correlations across forest ages and diameter classes. The results showed that (1) Functional traits exhibited varying degrees of intra-specific variation, with LA having the highest coefficient of variation (21.66%) and LPC is lowest (9.31%). (2) Forest age had a stronger influence on trait variation than diameter class, with all traits differing significantly across ages, while only WD varied significantly among diameter classes. (3) PC1 (25.5%) and PC2 (19.4%) together explained approximately 44.9% of the total variation, with PC1 primarily reflecting functional trait changes driven by forest age. PCA results showed that LA and CHL tended to exhibit higher values in young forests, whereas SLA, LDMC, LPC, and LNC had relatively higher values in mature forests. This pattern suggests a shift in functional trait expression from resource acquisition to resource conservation strategies with increasing forest age. (4) Significant positive correlations between LNC and LPC, and negative correlations between SLA and LDMC, were observed in most groups, except in large-diameter trees at the over-mature stage. adjusts trait combinations to enhance fitness across developmental stages. Juvenile trees adopt traits favoring efficient light and nutrient use to support rapid growth and competition. Middle-aged trees prioritize balanced water and nutrient use to maintain productivity and resist disturbances. Mature trees focus on sustained resource use and offspring protection to support ecosystem stability and regeneration. These findings reveal age-specific adaptive strategies and provide insights into the coordination and trade-offs among traits in response to environmental conditions.
功能性状的种内变异及其相互关系反映了植物如何分配资源、适应环境并随着环境变化而进化。本研究采用空间换时间的方法，调查了三个林龄（15年、30年和50年）人工林中的八个功能性状——叶面积（LA）、比叶面积（SLA）、叶干物质含量（LDMC）、叶绿素含量（CHL）、叶氮含量（LNC）、叶磷含量（LPC）、小枝组织密度（TTD）和木材密度（WD）。我们研究了不同林龄和径级间性状值、种内变异和性状相关性的差异。结果表明：（1）功能性状表现出不同程度的种内变异，其中叶面积的变异系数最高（21.66%），叶磷含量最低（9.31%）。（2）林龄对性状变异的影响大于径级，所有性状在不同林龄间差异显著，而只有木材密度在不同径级间差异显著。（3）主成分1（PC1，25.5%）和主成分2（PC2，19.4%）共同解释了总变异的约44.9%，PC1主要反映了由林龄驱动的功能性状变化。主成分分析结果表明，叶面积和叶绿素含量在幼龄林中往往表现出较高的值，而比叶面积、叶干物质含量、叶磷含量和叶氮含量在成熟林中相对较高。这种模式表明，随着林龄的增加，功能性状表达从资源获取策略向资源保护策略转变。（4）在大多数组中观察到叶氮含量和叶磷含量之间存在显著正相关，比叶面积和叶干物质含量之间存在负相关，但过熟阶段的大径级树木除外。植物会调整性状组合以提高整个发育阶段的适应性。幼树采用有利于高效利用光照和养分的性状来支持快速生长和竞争。中年树优先平衡水分和养分利用以维持生产力并抵御干扰。成熟树专注于持续的资源利用和后代保护以支持生态系统的稳定性和更新。这些发现揭示了特定年龄的适应策略，并为性状响应环境条件的协调和权衡提供了见解。
