Search

Fine roots are essential for terrestrial biogeochemical cycles. Mycorrhizal fungi's functions in regulating the uptake of carbon (C), nitrogen (N), and phosphorus (P) in plants are increasingly being recognized. However, the influence of mycorrhizae on Chinese plants' fine-root stoichiometry has not been considered. Herein, 772 plants with identified mycorrhizal types were divided into arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) types to investigate the differences in their fine-root stoichiometry and their driving factors. The results showed that the AM and ECM fine-root stoichiometries were significantly different (p < 0.001; p < 0.05). The AM plants' fine-root stoichiometry was mainly affected by the soil environment (8.76–90.12%), while ECM plants were more sensitive to climatic factors (23.51–52.41%). Further analysis showed that the mean annual temperature (MAT) was significantly correlated with AM plants' fine-root C and P and ECM plants' fine-root N and P. Mean annual precipitation (MAP) was significantly correlated with all AM plants' fine-root elements (p < 0.01) but was only negatively correlated with ECM fine-root P. It was concluded that the mycorrhizal type affects the response of the fine-root stoichiometry to climate and soil variations. Therefore, the mycorrhizal effect deserves attention when studying the relationship between plant nutrient uptake and environmental changes. [ABSTRACT FROM AUTHOR]

Leaf nitrogen (N) and phosphorus (P) are the most important functional traits in plants which affect biogeochemical cycles. As the most widely observed plant–fungus mutualistic symbiosis, mycorrhiza plays a vital role in regulating plant growth. There are different types of mycorrhiza with various ecological functions in nature. Drought, as a frequent environmental stress, has been paid more and more attention due to its influence on plant growth. Numerous studies have confirmed that drought affects the concentration of N and P in plants, but few studies involve different mycorrhizal types of plants. In this study, the differences of N and P between arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants under different drought patterns, drought duration and cultivation conditions were explored based on a dataset by a meta-analysis. Drought stress (DS) showed negative effects on AM plant N (−7.15%) and AM plant P (−13.87%), and a positive effect on AM plant N:P ratio (+8.01%). Drought significantly increased N and the N:P ratio of ECM plants by 1.58% and 3.58%, respectively, and decreased P of ECM plants by −2.00%. Short-term drought (<30 d) reduces more N and P than long-term drought (<30 d) in AM plant species. The duration of drought did not change the N concentration of ECM plant N, while short-term drought reduced ECM plant P. The effects of N and P on DS also varied with different planting conditions and functional groups between AM and ECM plants. Therefore, mycorrhizal effects and stoichiometry of N and P play a key role in plant response to drought. So mycorrhizal effects should be considered when studying plant responses to drought stress. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi (AMF) can not only improve soil and plant health, but also alter the accumulation of contaminants in plants. Here, the effects of AMF on the contents of organic contaminants and the underlying mechanisms are summarized. Data show that AMF widely occur in sites contaminated with organic chemicals. In most cases, AMF improve plant tolerance to organic contaminants and enhance crop growth, leading to increased biomass of the crops. Overall, AMF decrease organic contaminant residues in crop shoots, but often cause increased accumulation of contaminants, especially persistent organic pollutants (POPs), in crop roots. The benefits and mechanisms behind AMF's role in ameliorating organic contaminant residues in crops can be summarized as follows: (1) increased biomass via improved mineral nutrition and water availability; (2) alleviation of oxidative stress induced by contaminants; (3) enhanced activities of contaminant degradation-related enzymes; (4) accumulation and sequestration of contaminants by AMF structures; (5) glomalin-related soil protein (GRSP)-triggered changes in bioavailability of contaminants; (6) stimulation of contaminant-degrading microorganisms in soil; (7) improved soil structure; and (8) reduced pesticide application via enhanced crop resistance to pathogens and improved competition with weeds. Finally, future challenges and perspectives regarding AMF's contribution to crop safety are proposed. [ABSTRACT FROM AUTHOR]