Institution: | 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100 China
Department of Agroecology, University of Bayreuth, Bayreuth, 95440 Germany
Chinese Academy of Sciences and Ministry Water Resources, Institute of Soil and Water Conservation, Yangling, 712100 China;2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100 China
Chinese Academy of Sciences and Ministry Water Resources, Institute of Soil and Water Conservation, Yangling, 712100 China;3. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100 China |
Abstract: | 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. |