水保所知识产出(1956---)知识库

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 inter-
specific interactions between a C4 grass (Bothriochloa ischaemum, a dominant species in natural grass-
lands) and a C3 legume (Lespedeza davurica, a subordinate species in natural grasslands) via AMF and plant
growth, by continuous
13 C and 15 N labelling, combined with soil enzyme analyses. The results of 15 N label-
ling revealed that P addition affected the shoot uptake of N via AMF by B. ischaemum and L. davurica differ-
ently. 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 facili-
tated 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 consis-
tent 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.