Soil depth-dependent C/N stoichiometry and fungal and bacterial communities along a temperate forest succession gradient
Soil depth-dependent C/N stoichiometry and fungal and bacterial communities along a temperate forest succession gradient
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温带森林演替梯度上土壤深度依赖的 C/N 化学计量以及真菌和细菌群落
DOI：
10.1016/j.catena.2021.105613
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发表时间：
2021-07-24
期刊：
影响因子：
6.2
通讯作者：
Yuan, Hai-Sheng
中科院分区：
文献类型：
--
作者：
Bai, Zhen;Ye, Ji;Yuan, Hai-Sheng
不同土层养分有效性的垂直分层和相关的微生物适应性沿着森林演替梯度不同。然而，这种年龄相关的营养状况和微生物动力学及其深度依赖性差异背后的驱动力仍然不清楚。为了弥补这些知识空白，本研究调查了中国东北长白山地区3种温带林分（35年、82年和200年）有机层（O）、表层矿质土壤（A）和矿质底土（B）中的碳（C）和氮（N）含量、碳和氮获取胞外酶活性以及真菌和细菌群落。O-层表现出与年龄相关的C/N比增加以及N%、酶（例如，β-N-乙酰氨基葡糖苷酶）活性以及真菌和细菌的丰富性和多样性。此外，占主导地位的早期阶段（即，35 y）O-层真菌和细菌的种类与N含量和共生特性呈正相关，如具有强大的调动有效养分的能力。然而，占主导地位的后期（即，200 y）O-层微生物种类与N含量呈负相关，与C含量和/或C/N比呈正相关，其特征是贫营养能力，以适应N缺乏和柠檬酸基质分解。然而，在A层和B层中，基质可用性（例如，C和N含量）和养分循环活动（例如，酶活性以及真菌和细菌的代谢）表现出从早期到中期降低的趋势（即，82 y）或从中期到后期呈上升趋势。这种不同的甚至相反的养分状况和微生物之间的适应分解的有机质和土壤层表明，地下的生物化学特性强烈地决定了凋落物质量演替和微生物反馈的深度依赖性分配的有效养分。
The vertical stratification of nutrient availability and related microbial adaptations in different soil horizons vary along forest succession gradients. However, the driving forces behind such age-related nutrient statuses and microbial dynamics and their depth-dependent distinctions remain unclear. To bridge these knowledge gaps, the current study investigated the carbon (C) and nitrogen (N) contents, C- and N-acquiring extracellular enzyme activities and fungal and bacterial communities in the organic layer (O), surface mineral soil (A) and mineral subsoil (B) in three temperate forest stands (35 years (y), 82 y and 200 y) in the Changbai Mountain region of northeastern China. The O-horizon presented age-related increasing C/N ratios as well as decreases in N%, enzyme (e.g., beta-N-acetyl-glucosaminidase) activities and fungal and bacterial richness and diversity. In addition, the dominant early-stage (i.e., 35 y) O-horizon fungal and bacterial species presented positive relationships with the N content and copiotrophic characteristics, such as a powerful ability to mobilize available nutrients. However, the dominant late-stage (i.e., 200 y) O-horizon microbial species were negatively related to the N content but positively associated with the C content and/or C/N ratio and were characterized by an oligotrophic capacity for adapting to N deficiency and recalcitrant substrate decomposition. In the A- and B-horizons, however, the substrate availability (e.g., C and N contents) and nutrient cycling activities (e.g., enzyme activities and fungal and bacterial diversities) exhibited either a decreasing tendency from the early to the middle stage (i.e., 82 y) or an increasing tendency from the middle to the late stage. Such different or even opposing nutrient statuses and microbial adaptations between the decomposed organic matter and soil horizons suggest that the below-ground biochemical characteristics are strongly determined by litter quality succession and microbial feedbacks to the depth-dependent allocation of available nutrients.