No abstract

Arbuscular mycorrhizal fungi (AMF) colonize the rhizosphere of plants and form a symbiotic association with plants. Mycorrhizal symbionts have diversified ecological roles and functions which are affected by soil conditions. Understanding the effects of different AMF inoculation on plants under varied nutritional conditions is of great significance for further understanding the effects of the external environment regulating mycorrhizal symbiosis on plant phenotypic traits. In this study, the effects of four AMF inoculation treatments on the growth and reproductive performance of cherry tomato (Solanum lycopersicum var. cerasiforme) were investigated under three nutrient levels by pot experiment. It was found that the growth-promoting effect of AMF on cherry tomato decreased with nutrient reduction, and the effects of the same AMF inoculation treatment on cherry tomato were different at different nutrient levels. Nutrient levels and AMF had interactive effects on flower characteristics, fruit yield, resource allocation, and seed germination of the cherry tomato. In addition, AMF could promote sexual reproductive investment. Nutrient levels and AMF also affected the accumulation of nitrogen and phosphorus in cherry tomato, and there were significant differences among different AMF inoculation treatments. The results indicated that nutrient differences could affect the symbiosis between AMF and plants, and confirmed that there were differences in the effects of the four AMF inoculation treatments on the growth and reproductive traits of plants. The differences in growth and reproduction characteristics of cherry tomato between different AMF inoculation treatments at different nutrient levels indicated that the effects of AMF mycorrhizal on the traits of cherry tomato were regulated by nutrients.

No abstract

Arbuscular mycorrhizal (AM) symbiosis in soil may be directly or indirectly involved in the reproductive process of sexually reproducing plants (seed plants), and affect their reproductive fitness. However, it is not clear how underground AM symbiosis affects plant reproductive function. Here, we reviewed the studies on the effects of AM symbiosis on plant reproductive fitness including both male function (pollen) and female function (seed). AM symbiosis regulates the development and function of plant sexual organs by affecting the nutrient using strategy and participating in the formation of hormone networks and secondary compounds in host plants. The nutrient supply (especially phosphorus supply) of AM symbiosis may be the main factor affecting plant's reproductive function. Moreover, the changes in hormone levels and secondary metabolite content induced by AM symbiosis can also affect host plants reproductive fitness. These effects can occur in pollen formation and transport, pollen tube growth and seed production, and seedling performance. Finally, we discuss other possible effects of AM symbiosis on the male and female functional fitness, and suggest several additional factors that may be involved in the influence of AM symbiosis on the reproductive fitness of host plants. We believe that it is necessary to accurately identify and verify the mechanisms driving the changes of reproductive fitness of host plant in symbiotic networks in the future. A more thorough understanding of the mechanism of AM symbiosis on reproductive function will help to improve our understanding of AM fungus ecological roles and may provide references for improving the productivity of natural and agricultural ecosystems.