Mechanistic understanding of interspecific interaction between a C4 grass and a C3 legume via arbuscular mycorrhizal fungi, as influenced by soil phosphorus availability using a 13C and 15N dual‐labelled organic patch

• Published in: The Plant journal : for cell and molecular biology 2021-10, Vol.108 (1), p.183-196
• Main Authors: Liu, Hongfei, Wu, Yang, Xu, Hongwei, Ai, Zemin, Zhang, Jiaoyang, Liu, Guobin, Xue, Sha
• Format: Article
• Language: English
• Subjects: 15N; arbuscular mycorrhizal fungi (AMF); Arbuscular mycorrhizas; Bothriochloa ischaemum; Dominant species; Fungi; Grasses; Grasslands; interspecific plant interaction; Interspecific relationships; Labeling; Legumes; Mineralization; mycorrhizal growth response; Nitrogen isotopes; Nutrients; Organic matter; Organic phosphorus; Organic soils; P addition; Phosphorus; Plant growth; plant nitrogen acquisition via AMF; Soil analysis; Soil conditions; Soil microorganisms; Soil organic matter; Soils
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.15434

SUMMARY Arbuscular mycorrhizal fungi (AMF) can improve plant nutrient acquisition, either by directly supplying nutrients to plants or by promoting soil organic matter mineralization, thereby affecting interspecific plant relationships in natural communities. We examined the mechanism by which the addition of P affects interspecific interactions between a C4 grass (Bothriochloa ischaemum, a dominant species in natural grasslands) and a C3 legume (Lespedeza davurica, a subordinate species in natural grasslands) via AMF and plant growth, by continuous 13C and 15N labelling, combined with soil enzyme analyses. The results of 15N labelling revealed that P addition affected the shoot uptake of N via AMF by B. ischaemum and L. davurica differently. Specifically, the addition of P significantly increased the shoot uptake of N via AMF by B. ischaemum but significantly decreased that by L. davurica. Interspecific plant interactions via AMF significantly facilitated the plant N uptake via AMF by B. ischaemum but significantly inhibited that by L. davurica under P‐limited soil conditions, whereas the opposite effect was observed in the case of excess P. This was consistent with the impact of interspecific plant interaction via AMF on arbuscular mycorrhizal (AM) benefit for plant growth. Our data indicate that the capability of plant N uptake via AMF is an important mechanism that influences interspecific relationships between C4 grasses and C3 legumes. Moreover, the effect of AMF on the activities of the soil enzymes responsible for N and P mineralization substantially contributed to the consequence of interspecific plant interaction via AMF for plant growth. Significance Statement The AMF can have a considerable influence on interspecific relationships, but a mechanistic understanding of how soil P availability affects the interspecific relationships mediated by AMF is currently lacking. Our study revealed that plant N uptake via AMF and the effect of AMF on the activities of soil enzymes responsible for N and P mineralization are important mechanisms that influence the interspecific relationships between C4 grasses and C3 legumes.