Arbuscular mycorrhizal fungi (AMF) have established themselves as pivotal allies in the realm of plant physiology, renowned for their remarkable contributions to augmenting both growth and resilience against environmental stresses. In this study, we embarked on a comprehensive investigation into the discernible impact of two distinct AMF species on a widely planted oat cultivar, ‘Qingyan No. 1’, when subjected to the austere conditions of a drought. The experimental design included three distinct AMF treatments (inoculation with Rhiaophagus intraradices, Funneliformis mosseae, or not), and the three water treatments were 75% of field capacity (well watered), 50% of field capacity (moderate drought), and 30% of field capacity (severe drought). The obtained results showed that the rate of inoculation under 75% FC for both AMF species was over 74%. Drought stress limited the growth and osmotic regulation of the oat plants. However, AMF inoculation observably increased the above-ground biomass under 75% FC and increased the root biomass under 30% FC. AMF inoculation also increased the root traits under 75% FC and 50% FC. R. intraradices inoculation increased the above-ground soluble sugar and soluble protein concentrations, and both AMF species showed decreased malondialdehyde (MDA) concentrations in the roots. Furthermore, the pervasive influence of drought stress exerted a discernible stranglehold on nutrient uptake in the oat plants, profoundly impacting the distribution of nutrients within the shoots and roots. Regardless of the drought stress treatment, the inoculation with both AMF species increased the P concentrations in the roots and the K and Mg concentrations in the roots, and the inoculation with R. intraradices increased the Ca concentration in the whole oat plant. Under 75% FC, the N concentration of the whole oat plant was significantly reduced by both AMF species. However, under 50% FC and 30% FC, the N concentrations in the shoots inoculated with both AMF species were close to that of the non-inoculated shoots. In summary, AMF improved the osmotic regulation and nutrient absorption and distribution of oat plants under drought stress and thus promoted the growth and biomass accumulation of oat plants.

Disturbance by small burrowing herbivores often has an impact on plant aboveground biomass of grassland because it makes grasslands into a mosaic of discrete vegetated surfaces and bare soil patches. This study focuses on the plateau pika (Ochotona curzoniae) to investigate the effect of the disturbance by a small burrowing herbivore on plant aboveground biomass through upscaling the quadrat scale to the plot scale across five sites. This study showed that the plateau pika disturbance reduced sedge biomass and increased forb biomass. In contrast, they did not affect plant community biomass, grass biomass and legume biomass at the quadrat scale across the five sites. At the plot scale, that is, when the bare soil patches with a lack of plants were considered, plateau pika disturbance induced lower aboveground biomass of the plant community, sedge and legumes, while it had no relationship with grass biomass and forb biomass. As the disturbance intensity increased, the aboveground biomass of the plant community and sedge decreased, whereas the grass biomass showed a hump-shaped trend. These results indicate that plateau pika disturbance might be not beneficial to alpine meadows given the aboveground biomass of the plant community at the plot scale. In contrast, the intermediate disturbance intensity improves the grazing quality of alpine meadows through the higher grass biomass. The findings of this study imply that the plot scale is better than the quadrat scale to investigate the influence of the disturbance by a small burrowing herbivore on the plant aboveground biomass, and that management of a small burrowing herbivore needs to consider its disturbance intensity.

Puccinellia distans is a perennial gramineous plant with the characteristics of drought and salt tolerance. It is a special pioneer plant for saline-alkali land improvement and is increasingly used for ecological restoration of saline-alkali grassland. However, the evolutionary relationship of P. distans is limited in study. In this study, the complete chloroplast genome sequence of P. distans was evaluated. The complete chloroplast genome of P. distans was 135,647 bp in length, containing a pair of inverted repeated (IR) regions (21,444 bp) that are separated by a large single-copy (LSC) region of 800,15 bp, and a small single-copy (SSC) region of 12,744 bp. A total of 129 functional genes were annotated, including 83 protein-coding genes (mRNA), 38 tRNA genes, and 8 rRNA genes. The phylogenetic relationships of 12 species indicated that P. distans was closely related to P. muttalliana. This complete chloroplast genome will provide a theoretical basis for species identification and biological research.

Epichloë endophytes not only affect the growth and resistance of their host plants but also confer nutrient benefits to parasitized hosts. In this study, we used Pedicularis kansuensis to parasitize Stipa purpurea, both with and without endophytic fungi, and to establish a parasitic system. In this study, endophytic fungal infection was found to increase the dry weight of the leaf, stem, and leaf sheath, as well as the plant height, root length, tiller number, aboveground biomass, and underground biomass of S. purpurea under root hemiparasitic stress. Meanwhile, the ¹³C allocation of the leaf sheaths and roots of S. purpurea increased as the density of P. kansuensis increased, while the ¹³C allocation of the leaf sheaths and roots of E+ S. purpurea was lower than that of E− S. purpurea. The ¹³C allocation of the stem, leaf sheath, and root of E+ S. purpurea was higher than that of its E− counterpart. Furthermore, the content of photosynthetic ¹³C and the ¹³C partition rate of the stems, leaves, roots, and entire plant of S. purpurea and P. kansuensis transferred from S. purpurea increased as the density of P. kansuensis increased. These results will generate new insights into the potential role of symbiotic microorganisms in regulating the interaction between root hemiparasites and their hosts.