Rhizosphere soil microorganisms are significant factors affecting plant growth, especially that of saline–alkali tolerant plants in the desert ecosystem. We performed high-throughput sequencing in order to identifying the fungal community structures and their relationships to the physicochemical properties of different soil layers for the desert plant, Anabasis aphylla, in its natural environment. The number of unique operational taxonomic units (OTUs) found in the bulk soil of the 0–20 cm layer contributed to the biggest percentage (24.13%) of the overall amount of unique OTUs. Despite the fact that there was a rather large variety of fungi in the bulk soil of A. aphylla, the number of dominating fungi, which included Ascomycota, Microascus, and Arachnomyces, was found to be in quite high abundance in the rhizosphere soil. In the 20–40 cm layer of rhizosphere soil, the phylum Ascomycota accounted for 84.78% of the total phyla identified, whereas the species Microascus and Arachnomyces accounted for 24.72% and 37.18%, respectively, of the total species identified. In terms of the soil physicochemical properties, electric conductivity was the primary environmental component influencing the dominant fungi. The findings of this research enhance our comprehension of dominant fungi distributions and relevant environmental factors affecting the saline–alkali tolerant desert plant, A. aphylla. The results also provide a theoretical basis to help elucidate fungi adaptation mechanisms to the saline–alkali environment and methods for their isolation and screening.

The alpine meadow of Zoige Plateau plays a key role in local livestock production of cattle and sheep. However, it remains unclear how animal grazing or its intensity affect nitrous oxide (N₂O) emissions, and the main driving factors. A grazing experiment including four grazing intensities (G0, G0.7, G1.2, G1.6 yak ha⁻¹) was conducted between January 2013 and December 2014 to evaluate the soil nitrous oxide (N₂O) fluxes under different grazing intensities in an alpine meadow on the eastern Qinghai–Tibet Plateau of China. The N₂O fluxes were examined with gas collected by the static chamber method and by chromatographic concentration analysis. N₂O emissions in the growing seasons (from May to September) were lower than that in non-growing seasons (from October to April) in 2013, 1.94 ± 0.30 to 3.37 ± 0.56 kg N₂O ha⁻¹ yr⁻¹. Annual mean N₂O emission rates were calculated as 1.17 ± 0.50 kg N₂O ha⁻¹ yr⁻¹ in non-grazing land (G0) and 1.94 ± 0.23 kg N₂O ha⁻¹ yr⁻¹ in the grazing land (G0.7, G1.2, and G1.6). The annual mean N₂O flux showed no significant differences between grazing treatments in 2013. However, there were significantly greater fluxes from the G0.7 treatment than from the G1.6 treatment in 2014, especially in the growing season. Over the two years, the soil N₂O emission rate was significantly negatively correlated with soil water-filled pore space (WFPS) and dissolved organic carbon (DOC) content as well as positively correlated with soil available phosphorus (P). No relationship was observed between soil N₂O emission rate and temperature or rainfall. Our results showed that the meadow soils acted as a source of N₂O for most periods and turned into a weak sink of N₂O later during the sampling period. Our results highlight the importance of proper grazing intensity in reducing N₂O emissions from alpine meadow. The interaction between grazing intensity and N₂O emissions should be of more concern during future management of pastures in Zoige Plateau.

Introduction: In the Qinghai–Tibet Plateau (QTP), alpine meadows are among the most noticeable reflection of global climate change. However, effects of global warming on soils hosting alpine meadows in the QTP, such as reduced moisture because of low precipitation, remain unclear.Methods: Here, the soil moisture content (SMC), pH, dissolved organic carbon (DOC), ammonium nitrogen (NH₄⁺–N), nitrate nitrogen (NO₃⁻–N) and available phosphorus (AP) contents in the QTP were analyzed. The changes in and stoichiometries of total carbon, nitrogen, and phosphorus (TC, TN, and TP), microbial biomass carbon, nitrogen, and phosphorus (MBC, MBN, and MBP), β-1,4-glucosidase (BG), β-1,4-N-acetylglucoaminosidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (ACP) in the 0–30 cm layer of soils associated with warming in a greenhouse in the QTP from 2015 to 2020 were characterized.Results: We found that warming in the greenhouse significantly decreased the SMC, NO₃⁻–N, MBC, MBN, MBP, BG, LAP, ACP, and enzymatic C:N ratio. The warming increased the DOC, NH₄⁺–N, AP, MBC:MBN, and enzymatic N:P ratios noticeably. The pH, TC, TN, TP, C:N, C:P, N:P, MBC:MBP, MBN:MBP, and enzymatic C:P ratios were minimally affected.Conclusion: The results showed that warming and isolation from precipitation promoted mineralization of N and P in the soil but did not significantly alter the cycling of elements in soils in an alpine meadow.

Background: As a common accompanying dispersal structure, specialized seed appendages play a critical role in the successful germination and dispersal of many plants, and are regarded as an adaptation character for plants survival in diverse environments. However, little is known about how the appendages modulate the linkage between germination and environmental factors. Here, we tested the responses of germination to seasonal environmental signals (temperature and humidity) via seed appendages using Atriplex centralasiatica, which is widely distributed in salt marshlands with dry-cold winter in northern China. Three types of heteromorphic diaspores that differ in morphology of persistent bracteole and dormancy levels are produced in an individual plant of A. centralasiatica. Results: Except for the nondormant diaspore (type A, with a brown seed enclosed in a persistent bracteole), bracteoles regulated inner seed dormancy of the other two dormant diaspore types, i.e., type B (flat diaspore with a black inner seed) and type C (globular diaspore with a black inner seed). For types B and C, germination of bracteole-free seeds was higher than that of intact diaspores, and was limited severely when incubated in the bracteole-soaking solution. Dormancy was released at a low temperature (< 10 °C) and suitable humidity (5–15%) condition. Oppositely, high temperature and unfit humidity induced secondary dormancy via inhibitors released by bracteoles. Type C with deeper dormancy needed more stringent conditions for dormancy release and was easier for dormancy inducement than type B. The germination windows were broadened and the time needed for dormancy release decreased after the bracteole flushing for the two dormant types in the field condition. Conclusions: Bracteoles determine the germination adaptation by bridging seeds and environmental signals and promising seedlings establishment only in proper seasons, which may also restrict species geographical distribution and shift species distributing ranges under the global climate change scenarios.