Abstract The ecological benefits provided by ecological assets play an important role in im-proving human well-being, but there are few feasible methods to describe their status and trends by combining the quantity and quality data of ecological assets. This study is based on LUCC and integrates data on the quantity and quality of ecological assets. Based on the ecological asset index (EQ and EQi), the ecological assets of the Shibing karst and the Libo-Huanjiang Karst heritage sites are quantitatively evaluated, and their influencing factors are qualitatively analyzed. The results show that, (1) The ecological assets of the Shibing Karst and the Libo-Huanjiang Karst are mainly forest ecological assets, accounting for 89.31% and 89.98% of the ecological assets of the heritage sites, respectively. The proportion of ecological assets in cropland, shrubs, grasslands, water bodies, and impermeable surfaces is small. (2) The ecological asset quality of the two heritage sites is similar, with a two-level differentiation state. The ecological asset quality of forests and shrubs is mainly excellent, good, and moderate, while the ecological asset quality of cropland and grassland is mainly inferior and poor. From the overall quality perspective, the ecological asset quality of both heritage sites has significantly improved. (3) From 2000 to 2021, the EQ of the Shibing Karst increased from 180.179 to 225.606. The EQ of the Libo-Huanjiang Karst has increased from 560.463 to 641.269. Among the EQi of the two sites, forest > cropland > shrubs > grassland in the Shibing Karst, and forest > shrubs > cropland > grassland in the Libo-Huanjiang Karst. The implementation of a series of eco-logical protection projects and heritage site protection and management plans is the main reason for the improvement of regional ecological assets. Overall, this method can quickly and accurately assess the status and trends of ecological assets, guide ecosystem management within heritage sites, and provide effective solutions for ecological asset assessment in other karst world heritage sites.
Water scarcity is the major limiting factor for oasis-desert agricultural production of cotton. It is necessary to improve cotton for drought tolerance and minimize drought-related crop losses, and the transgenic approach is efficient for cotton improvement. In order to evaluate the value of ScALDH21 transgenic cotton (G. hirsutum L.), it was tested in the main cotton region of south Xinjiang, in an environment of extreme drought around the desert. Transgenic cotton, overexpressing aldehyde dehydrogenase gene (ScALDH21) from the desiccation-tolerant moss Syntrichia caninervis in cotton variety Xin Nong Mian 1, was field-tested under six treatments based on three irrigation schedules and two irrigation levels (full (FI) and deficit (DI) irrigation) as follows: root zone model-simulated forecast irrigation (F) (FFI and FDI), soil moisture sensor-based irrigation (S) (SFI and SDI), and flood irrigation based on experience estimates (E) (EFI and EDI) to evaluate growth and yield performances. The results revealed that plant height and leaf area increased significantly in ScALDH21-transgenic cotton genotypes under all treatments. Physiological parameters such as chlorophyll content, net photosynthesis rate, and instantaneous water use efficiency were not significantly highly in transgenic lines compared to non-transgenic plants (NT). However, transgenic lines showed significantly improved yield and superior fiber quality than NT plants regardless of irrigation. The results demonstrate that ScALDH21-transgenic lines were excellent compared to NT plants under different water deficiency conditions. The study also provides guidelines for optimal irrigation protocol and minimum water requirements for the use of the ScALDH21-transgenic cotton lines in arid zones.
Context. The intrinsic TeV emission of some BL Lacs are characterized by a hard spectrum (the hard-TeV spectrum) after correcting for the extragalactic background light. The hard-TeV spectra pose a challenge to conventional one-zone models, including the leptonic model, the photohadronic model, the proton synchrotron model, etc. Aims. In this work, we study if the one-zone hadronuclear (pp) model can be used to interpret the hard-TeV spectra of BL Lacs without introducing extreme parameters. Methods. We give analytical calculations to study if there is a parameter space and the charge neutrality condition of jet can be satisfied when interpreting the hard-TeV spectra of BL Lacs without introducing a super-Eddington jet power. Results. We find that in a sample of hard-TeV BL Lacs collected by Xue et al. (2019a), only the hard-TeV spectrum of 1ES 0229+200 could be explained by gamma-ray from pi-0 decay produced in the pp interactions, but at the cost of setting a small radius of the radiation region that comparable to the Schwarzschild radius of the central black hole. Combining with previous studies of other one-zone models, we suggest that the hard-TeV spectra of BL Lacs cannot be explained by any one-zone models without introducing extreme parameters, and should originate from the multiple radiation regions.
Soil salinization poses a global threat to terrestrial ecosystems. Soil microorganisms, crucial for maintaining ecosystem services, are sensitive to changes in soil structure and properties, particularly salinity. In this study, contrasting dynamics within the rhizosphere and bulk soil were focused on exploring the effects of heightened salinity on soil microbial communities, evaluating the influences shaping their composition in saline environments. This study observed a general decrease in bacterial alpha diversity with increasing salinity, along with shifts in community structure in terms of taxa relative abundance. The size and stability of bacterial co-occurrence networks declined under salt stress, indicating functional and resilience losses. An increased proportion of heterogeneous selection in bacterial community assembly suggested salinity’s critical role in shaping bacterial communities. Stochasticity dominated fungal community assembly, suggesting their relatively lower sensitivity to soil salinity. However, bipartite network analysis revealed that fungi played a more significant role than bacteria in intensified microbial interactions in the rhizosphere under salinity stress compared to the bulk soil. Therefore, microbial cross-domain interactions might play a key role in bacterial resilience under salt stress in the rhizosphere.
Plants have evolved complex molecular, cellular, and physiological mechanisms to respond to environmental stressors. Genetic manipulationhas represented an important potential method for improving water deficit tolerance in crops. Aldehyde dehydrogenases are involved in cellular responses to oxidative stress to protect against a variety of environmental stressors. The Syntrichia caninervis Mitt. ALDH21 gene plays a role in plant responses to abiotic stresses, and overexpression of this gene in tobacco ( Nicoiana tabacum L.) and cotton ( Gossypium hirsutum L.) decreases their sensitivity that improves tolerance to drought and salt stresses. To test the possibility that transgenic cotton constitutively expressing ScALDH21 may be suitable for cultivating under water deficit conditions, phenotype, physiological response, and yield of transgenic ScALDH21 cotton were measured in managed treatment plots and under field conditions. Overexpression of ScALDH21 in cotton resulted in higher net photosynthetic rate, less cellular damage, more cellular protective compounds, and enhanced growth compared with nontransgenic (NT) cotton under drought stress in managed treatment plots. Yield of transgenic cottons under deficit irrigation condition was increased above that for NT plants measured under full irrigation conditions. Under field conditions, transgenic cotton yield increased ∼10.0% under full irrigation and ∼18.0% under deficit irrigation conditions compared with NT. Fiber quality of transgenic cotton lines was also improved compared with NT under both full and deficit irrigation. These results suggest that transgenic ScALDH21 cotton is a viable candidate material for improving crop yields in water‐limited agricultural production systems.
The decline in agricultural productivity because of soil salinization has become a global problem in recent years. Biofertilizers show great potential for soil improvement as a sustainable strategy; however, their effectiveness in improving saline soils and enhancing plant growth under saline stress is poorly understood. We assessed the effectiveness of biofertilizers in improving saline soils and enhancing crop growth under saline stress and investigated the related potential mechanisms. Changes in soil physicochemical properties, plant physiological parameters, and soil microbial communities were analyzed using pot experiments. The results showed that biofertilizer application reduced total soluble salts in the soil by 30.8% and increased Brassica rapa L. biomass by 8.4 times. Biofertilizer application increased soil organic matter, total nitrogen, and available phosphorus by 56.1%, 57.0%, and 290%, respectively. Simultaneously, superoxide dismutase, catalase, chlorophyll a, chlorophyll b, total soluble sugar, and proline levels also increased by 89.5%, 140%, 110%, 190%, and 130%, respectively. Biofertilizers increased the abundance of Bacillus and Planococcus and decreased the abundance of Mortierella and Aspergillus, which could potentially be the underlying reason for the promotion of plant growth. Overall, the results of this study demonstrate the efficacy of biofertilizers in improving saline soils and that the application of biofertilizer could greatly promote agricultural production.
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