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Objective: To isolate and purify the polysaccharides from Lycium barbarum and study its in vitro antioxidant activity and in vivo anti-aging effect. Methods: Crude polysaccharides from Lycium barbarum were obtained by water extraction and alcohol precipitation, and then LBP was isolated and purified from crude polysaccharides by Sevage reagent and DEAE-52 cellulose ion exchange resin. By measuring the scavenging ability of LBP to DPPH free radical, hydroxyl radical and ABTS+ free radical, and Fe3+ reduction, the antioxidant ability of LBP in vitro was evaluated. The aging mouse model was established by D-galactose. After administration, the body weights and organ indexes of mice in each group were compared. The levels of MDA, SOD, GSH-Px and CAT in serum, liver and brain were measured. The protein expression of Nrf-2 and HO-1 in liver tissue was detected by Western blotting. Results: The content of LBP after isolation and purification was 86.64%±2.34%. The IC50 values of scavenging ability of LBP to DPPH free radical, hydroxyl radical and ABTS+ free radical were 0.2081±0.0182, 0.7132±0.0220 and 0.3646±0.0138 mg/mL, respectively. Compared with the model group, the body weights and organ indexes of the mice in positive and high dose of LBP groups were significantly increased (P<0.05 or P<0.01). The levels of SOD, CAT and GSH-Px in serum, liver and brain of mice in positive and high dose of LBP groups were significantly increased, and the level of MDA was significantly decreased (P<0.01). The expression level of Nrf-2 protein in liver tissue increased significantly except for in the low dose of LBP group (P<0.05), and the expression level of HO-1 protein increased significantly in all groups (P<0.05 or P<0.01). Conclusion: LBP from Lycium barbarum has strong antioxidant ability and certain anti-aging effect, and its mechanism may be related to Nrf-2/HO-1 signal pathway. [ABSTRACT FROM AUTHOR]

It is of great significance to systematically analyze the characteristics of the regional grain supply and demand balance, reveal the influence mechanism of crop sustainable development, and put forward effective countermeasures to achieve the goal of food security. This paper aims at addressing the unique geographical characteristics of Northwest China and the current lack of research on its food security. This paper systematically analyzes the temporal and spatial variation characteristics of the regional grain production, consumption and food security level. The main factors affecting regional food security are examined, and we put forward effective suggestions to promote regional sustainable production. The results show that the average annual growth rate of grain production in Northwest China from 2000 to 2021 was 3.4%, and the years of increased grain production accounted for 77.3%. The main reason for the increase in grain production was the increase in yield per unit area (average annual growth of 2.8%), of which the rice yield was the largest, up to 7.3 t/ha. Maize and wheat accounted for 60.7% and 23.4% of the total grain production in the region, respectively. From the perspective of the regional structure, Inner Mongolia contributed the most to the grain production in the region, accounting for 33.5% of the total output. Xinjiang, Shanxi, Shaanxi, Gansu, Ningxia and Qinghai contributed 17.1%, 15.4%, 15.2%, 13.0%, 4.5% and 1.3%, respectively, to grain production. From the perspective of the dietary structure, the grain consumption pattern in Northwest China has gradually changed from raw grains to animal products, which has undoubtedly increased the regional demand for grain. At present, since the increase in output is greater than the demand for food, the food self-sufficiency rate in the region has increased from 0.81 to 1.28. Since the grain yield per unit area in Xinjiang and Ningxia has a relative advantage over other provinces, to achieve regional food security for a long time, moderately increasing the grain planting area in these two provinces will help to promote regional food security. In addition, as the grains produced in the region are mainly wheat and corn, the yield level of wheat and corn in Xinjiang and Qinghai has a comparative advantage within Northwest China. Therefore, moderately increasing the planting area of wheat and corn in Xinjiang and Qinghai is of great significance in ensuring regional food security. The research results can provide theoretical support for the realization of regional food security and provide a reference for other regions in the world, to better serve global food security. [ABSTRACT FROM AUTHOR]

Climacium dendroides is a rare bryophyte resource with important medicinal value, which is mainly concentrated in the southwest and northeast China. In recent years, we found in the wild investigation that the population of C. dendroides had shrunk. In our study, based on high-resolution environmental variables and geographical occurrence records, the Maximum Entropy Model (MaxEnt) combined with ArcGIS was used to predict the spatial-temporal distributional pattern of C. dendroides in China under the current and future scenarios. Simulation results revealed that the total suitable area decreases by more than a third (–36.02%) in future scenarios. Further, the distributional centers moved to the northwest. Annual precipitation, max temperature of warmest month, and annual mean air temperature were the key environmental factors affecting the distribution of C. dendroides. Global warming coupled with the adverse effects of anthropogenic activities might accelerate the disappearance of suitable habitats for C. dendroides. Overall, our research provides useful indications for protecting the diversity of medical bryophytes and for their conservation. Supplemental data for this article is available online at http://dx.doi.org/10.1080/11263504.2021.1906348 [ABSTRACT FROM AUTHOR]

Knowledge of the characteristics of N2O emissions and the influential mechanism is of great significance to mitigate greenhouse gas emissions in semi-arid areas. In the present study, a three-year water-control study was conducted; three simulated rainfall amounts (heavy, normal, and light rainfall = 275, 200, and 125 mm, respectively), two wheat (Triticum aestivum L.) planting modes (RF (ridge–furrow mulching system) and TF (traditional flat planting)) and four supplementary irrigation amounts (150, 75, 37.5, and 0 mm) were set up. The effects of different cultivation methods and irrigation amounts on soil N2O emissions, the soil water content, available nitrogen content, and denitrifying enzyme activity were investigated to clarify the N2O emission mechanism in winter wheat fields (Triticum aestivum L.). The results obtained after three years showed that compared with TF, the N2O emissions under RF decreased by 21.62–30.72% (p < 0.001), whereas the soil water content increased by 6.26–8.82%, the available nitrogen content decreased by 1.71–16.24%, and the denitrifying enzyme activities increased by 0.2–24.16% under heavy rainfall conditions. Under conditions with normal and light rainfall, the N2O emission fluxes under RF increased by 3.66–12.46% and 6.08–15.57% (p > 0.05), while the soil water contents increased by 6.13–11.49% and 8.05–13.88%, the soil available nitrogen contents decreased by 11.0–21.42% and 19.93–34.44%, and the denitrifying enzyme activities increased by 0.01–24.08% and 0.03–20.79% compared with TF. Principal component analysis showed that the main factors related to N2O emissions under RF were the soil moisture content and available nitrogen content; these factors combined explained 94.37% the variation of the N2O emissions. However, the main factors under TF were the soil moisture content and denitrifying enzyme activity; these factors combined explained 85.81%. In the heavy and normal rainfall years, compared with TF, using RF and 75 mm irrigation achieved the goal of reducing water usage as well as decreasing the N2O emissions (or N2O increase was not significant). In light rainfall years, RF with 150 mm irrigation obtained significant reductions in water usage compared with TF but it also increased the N2O emission flux. Under different rainfall years, the yield of RF increased by 2.89–50.44% compared with the TF system, and the increase in wheat grain yield increased with decreasing rainfall. [ABSTRACT FROM AUTHOR]