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高节竹叶片生态化学计量特征和养分重吸收效率的种间竞争效应
Inter-Specific Competition Effects on Ecological Stoichiometry and Nutrient Resorption Efficiency in Phyllostachys prominens Leaves
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摘要: 以高节竹纯林(PP)为对照,对比分析高节竹−毛竹混交林(PM)和高节竹−针阔叶树混交林(PB)2种竞争条件下的生态化学计量特征。通过测定不同林分中高节竹成熟叶和衰老叶的碳(C)、氮(N)、磷(P)和钾(K)元素含量,解析养分重吸收规律,并运用结构方程模型(PLS−SEM)探讨种间竞争对高节竹养分利用策略的影响。结果表明:与PP相比,PM和PB中高节竹成熟叶和衰老叶的N和P含量显著降低,C含量无显著变化;PB中K含量显著高于PP和PM。与PP相比,PM和PB中高节竹叶片的C/N、C/P和N/P显著提高,其中PB中的C/N、C/P和N/P显著高于PM;PM和PB中N/K显著低于PP。与PP相比,PM和PB中N和P的重吸收效率(NRE和PRE)显著提高,其中PM中K的重吸收效率(KRE)最高。PLS−SEM分析显示,种间竞争通过调控成熟叶养分含量和衰老叶化学计量比,显著影响NRE和PRE。高节竹在不同竞争环境下采取差异化的养分利用策略:与针阔叶树竞争时优先提升P的利用与重吸收能力,而与毛竹竞争时则强化K的利用效率,从而增强其生态适应性和生长潜力。Abstract: Using pure forests of Phyllostachys prominens (PP) as the control, we compared the ecological stoichiometry of bamboo leaves in mixed forests of Ph. prominens and Ph. edulis (PM), as well as Ph. prominens and broadleaved-conifer mixed trees (PB), under competitive conditions. By measuring the carbon (C), nitrogen (N), phosphorus (P), and potassium (K) content in mature and senescent leaves of Ph. prominens across these different forest types, we analyzed nutrient resorption patterns and employed partial least squares structural equation modeling (PLS-SEM) to explore the effect of interspecific competition on bamboo's nutrient utilization strategies. The results show that: Compared to PP, N and P contents in both mature and senescent leaves of Ph. prominens were significantly reduced in PM and PB, while C content remained unchanged. K content was significantly higher in PB than in PP and PM. The C/N, C/P, and N/P ratios in Ph. prominens leaves were significantly higher in PM and PB compared to PP, with PB showing significantly higher values than PM. Conversely, the N/K ratio was significantly lower in PM and PB than in PP. N and P resorption efficiency (NRE and PRE) was significantly higher in PM and PB compared to PP, with PM exhibiting the highest K resorption efficiency (KRE). PLS-SEM analysis revealed that interspecific competition significantly influenced NRE and PRE by regulating the nutrient content in mature leaves and the stoichiometric ratios in senescent leaves. In conclusion, Ph. prominens adopts differentiated nutrient utilization strategies in response to interspecific competition: when competing with broadleaved-conifer mixed trees, it prioritizes P utilization and resorption, while enhancing K utilization efficiency when competing with Ph. edulis, thereby improving its ecological adaptability and growth potential.