Abstract

Aims

All organisms need elements in fixed proportions for carrying out normal metabolic processes and how flexible they are depends on how effective they are utilizing these resources from external sources. It is important to understand the interactions among plant, soil and microbial biomass carbon (C), nitrogen (N) and phosphorus (P) stoichiometry under different conditions of resource supply.

Methods

We conducted a pot experiment on one-year-old Robinia pseudoacacia seedlings for nearly five months under different water, nitrogen and phosphorus supplies, and we determined plant, soil and microbial biomass C, N and P stoichiometry.

Important Findings

We found that plant, soil and microbial nutrients and stoichiometry exhibited a certain degree of plasticity in response to the changes in water and nutrient conditions in their environments. Variation partitioning analysis showed that root stoichiometry accounted for a large part of the variance in microbial stoichiometry. Structural equation modeling further revealed that root stoichiometry and leaf stoichiometry were two direct factors affecting microbial biomass C:N and C:P, and that root stoichiometry had the greatest direct effect. In addition, the degree of homeostasis for microbial biomass C and C:P was more sensitive to changes in soil nutrients than changes in other factors, and other elements and elemental ratios displayed strict homeostasis. These results highlight the importance of studying microbial stoichiometry in improving our understanding of nutrient cycling of the plant-soil system under different water and nutrient supply.

中文翻译：

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刺槐植物-土壤系统对可变水和养分供应的化学计量稳态响应

摘要

目标

所有生物都需要固定比例的元素来执行正常的代谢过程，它们的灵活性取决于它们从外部来源利用这些资源的效率。了解不同资源供应条件下植物、土壤和微生物生物量碳 (C)、氮 (N) 和磷 (P) 化学计量之间的相互作用非常重要。

方法

我们在不同的水、氮和磷供应条件下对一岁的刺槐幼苗进行了近五个月的盆栽试验，并确定了植物、土壤和微生物生物量的 C、N 和 P 化学计量。

重要发现

我们发现植物、土壤和微生物的养分和化学计量在响应其环境中水和养分条件的变化时表现出一定程度的可塑性。变异分配分析表明，根化学计量占微生物化学计量变异的很大一部分。结构方程模型进一步揭示了根化学计量和叶片化学计量是影响微生物生物量C:N和C:P的两个直接因素，其中根化学计量具有最大的直接影响。此外，微生物生物量C和C:P的稳态程度对土壤养分的变化比其他因素的变化更敏感，其他元素和元素比例表现出严格的稳态。