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Aims: Multi-elemental stoichiometry can represent the biogeochemical niches of species, which can further guide community assemblage. Mycorrhizae play a key role in plant elemental acquisition. Whether and how mycorrhizal type influences the plant multi-elemental stoichiometries and elemental coordination in above- and belowground organs, however, remain unclear. Methods: We determined the concentrations of C, N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, Na, Pb and Sr and some elemental ratios in the leaves and roots of arbuscular mycorrhizal (AM) trees (Phoebe bournei, Schima superba, Michelia maudiae and Cunninghamia lanceolata) and ectomycorrhizal (ECM) trees (Cyclobalanopsis glauca, Pinus massoniana and P. elliottii) in subtropical China. The effects of root traits and soil abiotic factors on elemental concentrations and ratios were reported. Results: The elemental concentrations and ratios differed substantially between the AM and ECM trees, indicating the their biogeochemical niches' differentiation. The C, P, Mg and Mn concentrations and the K:Mg andCa:Mg ratios for AM and the N, Mn and Na concentrations and the Fe:Mn ratio for the ECM species were strongly correlated between leaves and roots, but the correlations were positive or negative depending on elemental composition and mycorrhizal type. The root branching ratio, branching intensity and length played important roles in the plant elemental stoichiometries. Conclusions: The biogeochemical niche's differentiation between the AM and ECM species emphasizes the important role of mycorrhizal type in the assemblage of co-occurring species. This study offers a new opinion for species choosing in mixed forests from the view of the biogeochemical niche's separation. [ABSTRACT FROM AUTHOR]

Aims: Phyllostachys praecox is one of the bamboo species that cultivated extensively in southern China. An organic material mulching technique is commonly adopted in winter to increase the yield of bamboo shoots and profits. However, P. praecox is inevitable to be declined when using the technique continuously. Accordingly, we conducted an aeration study to explore the mechanism of the bamboo recession. Methods: P. praecox were subjected to mulching and aeration treatments for 50 days, antioxidant enzymes, anaerobic respiratory metabolizing enzymes, and photosynthesis characteristics were investigated in root and leaf tissues. Results: The mulching treatment led to bamboo hypoxia stress, while the aeration improved bamboo growth. Compared with mulching treatment, the aeration treatment significantly increased the soil oxygen content. Aeration treatment led to increases in the bamboo root respiratory activity by 19.74%, but decreased ADH, LDH, PDC, SOD, CAT, APX, GR activities by 64.98%, 36.58%, 57.78%, 21.57%, 33.33%, 22.60%, and 32.06%, respectively. Moreover, the aeration treatment greatly enhanced chlorophyll synthesis and improved bamboo photosynthesis. Conclusions: Soil hypoxia induced by the organic material mulching inhibited bamboo growth, which might be the critical factor in the bamboo recession. Our results indicated aeration was conducive to preventing the degeneration of the P. praecox bamboo forest. [ABSTRACT FROM AUTHOR]