Characteristics of Culturable Microbial Community in Rhizosphere/Non-rhizosphere Soil of Potentilla Fruticosa Population in Alpine Meadow Elevation Gradient

Potentilla fruticosa is a typical shrub of alpine meadows with canopy effects that can greatly influence soil fertility and microbiological parameters. Changes in rhizosphere microorganisms can reflect the response of these plants to environmental changes. This study aimed to examine the rhizosphere and non-rhizosphere of P. fruticosa on the amount of selected microorganisms and main environmental factors at different elevation gradients (3,000, 3,250, 3,500, 3,750, and 4,000 m). The results suggested that bacteria were predominant of the microbial soil community in the rhizosphere and non-rhizosphere, while fungi and actinomycetes represented the minority. With the increase of altitude, the total amount of microbial, bacteria, and actinomycetes in the rhizosphere and non-rhizosphere of P. fruticosa showed a downward trend, and microbial functional groups showed that the “hump shape” changed, but the fungi showed the opposite. Variance inflation factor (VIF) screening environmental factors and path analysis were obtained. In the rhizosphere soil, bacteria were affected by Soil organic carbon (SOC), and soil bulk density (SBD) became the main environmental limiting factor with the increase of altitude. The main environmental limiting factor of actinomycetes changed from SBD to Soil total (ST). In the non-rhizosphere soil, the bacteria and actinomycetes changed from ST to SOC and SBD, respectively. The main environmental limiting factor of the fungi was SOC in the rhizosphere and non-rhizosphere. Soil water content (SWC) was the main environmental determinant factor for all microbial groups, microbial functional groups were related to Soil total nitrogen (STN). Our results help to understand the relationship between nutrient cycling and the ecosystem function of alpine meadow plant soil microorganisms and provide theoretical support for alpine meadow ecosystem restoration, biodiversity protection, and the use of microbial resources.

Leaf Stoichiometry of Potentilla Fruticosa Across Elevations Ranging from 2400 m to 3800 m in China’s Qilian Mountains (Northeast Qinghai-Tibetan Plateau)

Background: Plant species have developed their individual leaf stoichiometries to adapt to changes in the environment. Changes in plant leaf stoichiometry with elevation are largely undocumented, but could provide information critical to protecting or enhancing a species’ growth and development and manage the ecosystem housing it. We investigate the leaf stoichiometry of Potentilla fruticosa L. along with different elevations in China’s Qilian mountains (Northeast Qinghai-Tibetan Plateau). This study aims to reveal how elevations effect of the leaf stoichiometry of Potentilla fruticosa L. along with various soil properties in China’s Qilian mountains .Results: In our study, we selected seven elevations 2,400 m, 2,600 m, 2,800 m, 3,000 m, 3,200 m, 3,500 m, and 3,800 m elevation. We sampled leaves at top and middle of P. fruticosa from each of seven elevations. Maximum and minimum leaf carbon (C) concentrations ([C]leaf) of 523.59 g kg-1 and 402.56 g kg-1 were measured at 2,600 m and 3,500 m, respectively. Showing a generally increasing trend with elevation, leaf nitrogen (N) concentration ([N]leaf) peaked at 3,500 m (27.33 g kg-1). Leaf phosphorus (P) concentration ([P]leaf) varied slightly over elevations of 2,400 m to 3,200 m, then dropped to a minimum (0.60 g kg-1) at 3800 m. While [C]leaf:[N]leaf, [C]leaf:[P]leaf and [N]leaf:[P]leaf varied little between 2,400 m and 3,000 m, at higher elevations they fluctuated somewhat, the latter two showing a decrease at 3,200 m followed by an increase at higher elevations. The soil organic C, pH, and soil total P were the main factors influencing P. fruticosa leaf stoichiometry. The limiting nutrients were P. Conclusions: We highlight the dependency of leaf stoichiometry on slope aspect and elevation. As P. fruticosa is a major alpine shrub in this region and plays an important role in maintaining ecological functions and services on the Qinghai-Tibetan Plateau, measures should be adopted to improve P. fruticosa growth by preventing P loss, especially at higher elevations where significant P losses occur due to high precipitation and sparse vegetation.

Morphological characteristics of Potentilla fruticosa in the urban ecosystem of Novosibirsk city

Changes in leaf morphological characteristics in Potentilla fruticosa growing under the transport and industrial pollution conditions in the city of Novosibirsk have been studied. Leaf morphological characteristics were determined by computer image analysis using geographical information systems (GIS). It was found that, in response to anthropogenic disturbance, the size of the assimilating organs of plants decreased by a factor of 1.2-4.5 and the leaf fluctuating asymmetry increased compared to these parameters in control plants; the urban area had a high level of environmental pollution, and the control area a low level.

Precipitation and seasonality affect grazing impacts on herbage nutritive values in alpine meadows on the Qinghai-Tibet Plateau

AimsGrasslands used for animal husbandry are chosen depending on the nutritive values of dominant herbage species. However, the influence of grazing in combination with precipitation and growing season on the nutritive values of dominant species has not been explicated.MethodsTo unveil the influence of the different grazing intensities on the nutritional values, an ecological study was formulated, namely fencing (G0), light grazing (G1), moderate grazing (G2) and high grazing (G3). This ambitious study was undertaken on the nutritive values of the four dominant species of herbage in an alpine meadow on the Qinghai-Tibet Plateau (QTP) during growing season (June–September) for two successive years, namely 2015 (rainy year) and 2016 (droughty year).Important FindingsWe found that (i) the nutritive value of Kobresia capillifolia, Polygonum viviparum and Caragana sinica was noticeably increased by grazing, but negligible effect on Potentilla fruticosa nutritive value was recorded. (ii) During the rainy year (2015), compared with G0, Polygonum viviparum and Potentilla fruticosa displayed 5.4 and 1.5% increases in the crude protein (CP) content and 8.5 and 2.4% increases in vitro true digestibility (IVTD), respectively, while the neutral detergent fibre (NDF) decreased by 13.5 and 0.9%, respectively. During the droughty year (2016), compared with G0, C. sinica and Potentilla fruticosa showed increases in the CP content by 4.3 and 1.3% and increases in the IVTD by 10.7 and 0.4%, respectively, during G3, while the NDF decreased by 6.0 and 1.0%, respectively. (iii) The nutritive values of all species were higher in the years when the rains were good. However, the nutritive values suffered heavily during drought conditions. Besides, the highest and lowest values of nutrition were detected in June and in September, respectively. The inter-seasonal and the inter-annual changes in the nutritional values of species were higher for K. capillifolia and Polygonum viviparum than for Potentilla fruticosa and C. sinica, suggesting that Potentilla fruticosa and C. sinica had higher water-use efficiency. (iv) Grazing clearly reduced the drought tolerance of three species and showed no effects on Potentilla fruticosa. (v) Grazing clearly increased the inter-month variation in the nutritional value of K. capillifolia and Polygonum viviparum but showed no effects on Potentilla fruticosa or C. sinica. Evidently, the grazing effects impacting the nutritional value of the dominant species of herbage exhibited conspicuous inter-annual and seasonal variations with species-specific influences and responses. Our findings are expected to have far-reaching implications enabling the authorities to arrive at strategic decisions and designing of relevant policies for the efficient management of the ecosystems ensuring the speed restoration of the QTP under severe grazing and extreme climatic circumstances.