Aims

The aim of this study was to investigate the mechanisms by which nitrogen (N) and phosphorous (P) additions affect plant C:N:P stoichiometry via changes in AMF communities in a Chinese fir plantation.

Methods

Experimental plots in a 10-year-old Chinese fir plantation were treated with N addition (LN, 30 kg•ha⁻¹•yr⁻¹, and HN, 60 kg•ha⁻¹•yr⁻¹) and P addition (LP, 20 mg•kg⁻¹, and HP, 40 mg•kg⁻¹) for 2 years starting from 2017. Soil properties, leaf C:N:P stoichiometry, and changes in AMF community composition and diversity were measured.

Results

N or P addition increased soil N availability, decreased P availability, and increased N:P in the leaves and soil. Changes in soil pH induced by N and P additions affected the colonization rate and spore density of AMF. AMF colonization rate was increased by N or P addition, and AMF diversity was increased by LN addition. N and P additions altered AMF species composition, and the dominant genus of the AMF in the soil was Glomus in all treatments. The interaction of N and P treatments had no significant effect on AMF diversity. AMF colonization rate and diversity, rather than its composition, affected leaf C:N:P stoichiometry.

Conclusion

N and P additions affected colonization rate and diversity of AMF though changes in soil pH, which drove leaf C:N:P stoichiometry, and potentially affected forest productivity via the fungi-soil-plant system.

中文翻译：

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氮和磷添加引起的丛枝菌根真菌定殖和土壤pH值影响杉木（Cunninghamia lanceolata）森林叶片C：N：P化学计量

目的

这项研究的目的是研究氮（N）和磷（P）的添加通过杉木人工林中AMF群落的变化影响植物C：N：P化学计量的机制。

方法

用添加氮（LN，30 kg•ha ^-1 •yr ^-1和添加HN，60 kg•ha ^-1 •yr ^-1）和磷（LP）处理10年龄杉木人工林的试验区。自2017年起为期2年，分别测定20 mg•kg ^-1和HP 40 mg•kg ^-1。测量了土壤性质，叶片C：N：P化学计量以及AMF群落组成和多样性的变化。

结果

氮或磷的添加增加了土壤氮素的利用率，减少了磷素的利用率，并增加了叶片和土壤中氮磷的含量。氮和磷的添加引起的土壤pH值的变化影响了AMF的定殖率和孢子密度。添加N或P增加了AMF定殖率，通过添加LN增加了AMF的多样性。氮和磷的添加改变了AMF的种类组成，在所有处理中，土壤中AMF的主要属是Glomus 。N和P处理的相互作用对AMF多样性没有显着影响。AMF的定殖率和多样性而不是其组成会影响叶片C：N：P的化学计量。

结论

氮和磷的添加虽然改变了土壤的pH值，但仍影响了AMF的定殖率和多样性，从而推动了叶片C：N：P的化学计量，并可能通过真菌-土壤-植物系统影响森林的生产力。