水保所知识产出(1956---)知识库

Arbuscular mycorrhizal fungi (AMF) regulate soil nutrient cycling, directly supplying a host plant with nitrogen (N). AMF
can also affect the outcome of interspecific interactions, but a mechanistic understanding of how soil N availability affects
AMF-mediated interspecific relationships is currently lacking. We selected one dominant (Bothriochloa ischaemum; C 4
grass) and one subordinate (Lespedeza davurica; legume) species in a natural grassland climax community to investigate
the mechanism by which AMF influence interspecific interaction (mixed and monoculture) under three levels of N addi-
tion (0, low, and high N addition). Under the non-N addition treatment, AMF preferentially supplied N to the roots of B.
ischaemum at the expense of N uptake by L. davurica, resulting in inhibited AMF benefits for L. davurica shoot growth.
Under the low N addition treatment, interspecific interaction via AMF promoted L. davurica growth. Compared to the
non-N addition treatment, N addition largely mitigated the effects, both positive (for B. ischaemum) and negative (for L.
davurica), of AMF-mediated interspecific interaction on plant N uptake via AMF. When soil N availability severely limited
plant growth, preferential N supply to the C 4 grass by AMF was important for maintaining the abundance of the dominant
species. When the N limitation for plant growth was alleviated by N addition, the interaction between AMF and soil micro-
organisms improved nutrient availability for the legume by stimulating activity of the enzyme responsible for soil organic
matter mineralization, which is important for maintaining the abundance of the subordinate species. These data could in-
fluence strategies for maintaining biodiversity.