Chen Youchao, Yin Shuwei, Shao Yun, Zhang Kerong
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
College of Life Sciences, Henan Normal University, Xinxiang, China.
Front Microbiol. 2022 Sep 23;13:999385. doi: 10.3389/fmicb.2022.999385. eCollection 2022.
Anthropogenic activities have dramatically increased nitrogen (N) and phosphorous (P) enrichments in terrestrial ecosystems. However, it is still unclear on how bacterial and fungal communities would respond to the simultaneously increased N and P enrichment. In this study, we used a field experiment to simulate N and P input, and examined the effects of N and P additions on the abundance, alpha-diversity, and community composition of soil bacteria and fungi in a riparian forest. Six nutrient-addition treatments, including low N (30 kg N ha year), high N (150 kg N ha year), low P (30 kg PO ha year), high P (150 kg PO ha year), low N+P, high N+P, and a control (CK) treatment were set up. We found that the N and P additions significantly affected bacterial abundance, community composition, but not the alpha diversity. Specifically, 16S, , and gene copy numbers were significantly reduced after N and P additions, which were correlated with decreases in soil pH and NO -N, respectively; Co-additions of N and P showed significantly antagonistic interactions on bacterial gene copies; Nutrient additions significantly increased the relative abundance of while reduced the relative abundance of . Mantel's test showed that the alteration in bacterial composition was associated with the changes in soil pH and NO -N. The nutrient additions did not show significant effects on fungal gene copy numbers, alpha diversity, and community composition, which could be due to non-significant alterations in soil C/N and total P concentration. In conclusion, our results suggest that soil bacteria are more sensitive than fungi in response to N and P enrichment; the alterations in soil pH and NO -N explain the effects of N and P enrichment on bacterial communities, respectively; and the co-addition of N and P reduces the negative effects of these two nutrients addition in alone. These findings improve our understanding of microbial response to N and P addition, especially in the context of simultaneous enrichment of anthropogenic nutrient inputs.
人为活动显著增加了陆地生态系统中的氮（N）和磷（P）富集。然而，细菌和真菌群落如何响应同时增加的氮和磷富集仍不清楚。在本研究中，我们通过田间试验模拟氮和磷输入，并研究了氮和磷添加对河岸森林土壤细菌和真菌的丰度、α多样性及群落组成的影响。设置了六种养分添加处理，包括低氮（30千克氮/公顷·年）、高氮（150千克氮/公顷·年）、低磷（30千克磷/公顷·年）、高磷（150千克磷/公顷·年）、低氮+磷、高氮+磷以及对照（CK）处理。我们发现，氮和磷添加显著影响细菌丰度和群落组成，但对α多样性无显著影响。具体而言，氮和磷添加后16S、、和基因拷贝数显著降低，分别与土壤pH值和硝态氮的降低相关；氮和磷共同添加对细菌基因拷贝表现出显著的拮抗作用；养分添加显著增加了的相对丰度，同时降低了的相对丰度。Mantel检验表明，细菌组成的改变与土壤pH值和硝态氮的变化相关。养分添加对真菌基因拷贝数、α多样性和群落组成未表现出显著影响，这可能是由于土壤碳氮比和总磷浓度无显著变化所致。总之，我们的结果表明，土壤细菌对氮和磷富集的响应比真菌更敏感；土壤pH值和硝态氮的变化分别解释了氮和磷富集对细菌群落的影响；氮和磷共同添加减轻了这两种养分单独添加的负面影响。这些发现增进了我们对微生物对氮和磷添加响应的理解，特别是在人为养分输入同时富集的背景下。
