Arbuscular Mycorrhizal Fungi Alter Plant and Soil C:N:P Stoichiometries Under Warming and Nitrogen Input in a Semiarid Meadow of China

How arbuscular mycorrhizal fungi drives herbaceous plants' C: N: P stoichiometry? A meta-analysis

Plant element stoichiometry is fundamental for preserving growth-related terrestrial ecosystem structures and functions. However, effects of arbuscular mycorrhizal fungi (AMF) on herbaceous plant element stoichiometry (carbon (C), nitrogen (N), and phosphorus (P)) remain unclear. In this study, we aimed at evaluating the potential effects of AMF on herbaceous plant C, N and P concentration and their C:N:P stoichiometry worldwide through a quantitative meta-analysis. We observed that AMF reduced C:P and N:P ratios in the shoot of plants by 35.83 % and 54.23 %, respectively, and in plant root organs by 36.24 % and 46.35 %, respectively. Conversely, C:N ratios increased in roots by 6.61 %. The negative effect of AMF on N:P and C:P ratios in plant shoots and root organs is mainly attributed to the plant benefits in P and N concentrations. AMF impact on plant C:N:P stoichiometry depends on fungal and plant functional group identities and soil nutrient availability. Our results suggest that plant functional group identity affects plant nutrient concentration, which, in turn, controls herbaceous plant C:N:P stoichiometry. Overall, we emphasize the importance of abiotic and biotic environmental factors in changing AMF effects on plant element stoichiometry. Therefore, clarifying the relationship between AMF and herbaceous plant C:N:P stoichiometry will improve our understanding of herbaceous plant stoichiometric variations in terrestrial ecosystems.

C, N, and P stoichiometry and their interaction with different plant communities and soils in subtropical riparian wetlands

Ecological stoichiometry represents the balance of nutrient elements under ecological interactions, which are crucial for biogeochemical cycles in ecosystems. Little is known about carbon (C), nitrogen (N), and phosphorus (P) ecological stoichiometry in aboveground biomass, roots, and soil, especially in the subtropical riparian wetlands. Here, eight dominate plant communities in riparian wetlands were chosen, and C, N, and P contents, and C:N:P ratios of aboveground biomass, roots, and soil were investigated. The results demonstrated that plant community had remarkable effects on the C:N:P stoichiometry in aboveground biomass, roots, and soil, which varied widely. C, N, and P concentrations in aboveground biomass were mostly higher than that in roots, while no significant difference was detected in C:N:P ratios. Moreover, there were higher soil C, N, and P contents in Cannabis indica plant communities; while lower soil N:P ratios suggested that riparian wetlands were more susceptible to N limitation, rather than P. Pearson correlation analysis and redundancy analysis (RDA) showed that there were strong associations among C, N, and P contents, and C:N:P ratios in aboveground biomass, roots, and soil, indicating that C, N, and P ecological stoichiometry of aboveground biomass were regulated by soil C, N, and P contents through the roots. In addition, the contents of C and N, and N and P exhibited a strong relationship according to linear regression. These findings suggested that the interactions among the C, N, and P stoichiometry were existed in the plant-soil system.

Diversity of arbuscular mycorrhizal fungi associated with acacia trees in southwestern Saudi Arabia

Acacia species produce extensive, deep root systems with a capacity to develop mycorrhizal symbioses that facilitate plant nutrition via enhanced soil nutrient absorption. This study aimed to evaluate the mycorrhizal status and the diversity of arbuscular mycorrhizal fungi (AMF) associated with acacia trees in southwestern Saudi Arabia. The mycorrhizal status varied greatly between species. The highest values of AMF root colonization and spore density were observed in the roots and in the rhizospheric soil of Acacia negrii. DNA was extracted from plant roots and the AMF large subunit ribosomal DNA (LSU rDNA) was amplified by a nested polymerase chain reaction. A total of 274 LSU rDNA cloned fragments from roots of the three acacia trees were sequenced. Phylogenetic analysis revealed a high AMF diversity, especially in Acacia tortilis. On the basis of LSU rDNA sequences, AMF was grouped into five genera: Glomus, Claroideoglomus, Acaulospora, Gigaspora, and Scutellospora. The genus Glomus fungi were the dominant colonizers of all three acacia species, while the genus Scutellospora fungi were found only in A. tortilis roots. The high AMF-acacia diversity suggests that AMF plays an important role in the sustainability of acacia species in the arid environment.