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Brassinosteroids (BRs) are a class of steroid hormones with great potential for use in crop improvement. De-repression is usually one of the key events in hormone signaling. However, how the stability of GSK2, the central negative regulator of BR signaling in rice (Oryza sativa), is regulated by BRs remains elusive. Here, we identify the U-box ubiquitin ligase TUD1 as a GSK2-interacting protein by yeast two-hybrid screening. We show that TUD1 is able to directly interact with GSK2 and ubiquitinate the protein. Phenotypes of the tud1 mutant are highly similar to those of plants with constitutively activated GSK2. Consistent with this finding, GSK2 protein accumulates in the tud1 mutant compared with the wild type. In addition, inhibition of BR synthesis promotes GSK2 accumulation and suppresses TUD1 stability. By contrast, BRs can induce GSK2 degradation but promote TUD1 accumulation. Furthermore, the GSK2 degradation process is largely impaired in tud1 in response to BR. In conclusion, our study demonstrates the role of TUD1 in BR-induced GSK2 degradation, thereby advancing our understanding of a critical step in the BR signaling pathway of rice.

Natural capital is a limited and irreplaceable factor for human welfare and sustainability. Natural capital includes natural capital flow and natural capital stock. When natural capital flow cannot meet the needs of regional development, it begins to consume natural capital stock. Therefore, the assessment of the current utilization status of natural capital flows and stocks is not only the basis for regional ecological construction evaluation but also an important indicator of the effectiveness of regional sustainable development strategies. This study uses the three-dimensional ecological footprint model to systematically and comprehensively evaluate the utilization status of natural capital flows and stocks in Hainan Province from 2005 to 2016. The driving factors behind changes in the natural capital stock are revealed using a partial least squares method. Our results indicate the following. (1) The per capita ecological footprint of Hainan Province is increasing at an annual rate of 3.87%, and the per capita ecological deficit is increasing at an annual rate of 5.85%. The ecological footprints are mainly composed of cropland and forest land and the account composition is dominated by the biological and energy accounts; (2) The growth of water body natural capital flow promotes the total natural capital flow consumption of Hainan Province from 2005 to 2016 with an annual average of 0.41%. The natural capital flow consumption is mainly in the north, northeast and southwestern cities and counties, and the growth rate of natural capital flow consumption is greatest in the central mountainous region; (3) The consumption of total natural capital stock is growing at an average annual rate of 4.49%, from a value of 2.97 times the sustainable resource consumption of Hainan Province in 2005, increasing to a factor of 4.81 times in 2016. The natural capital stock consumption is mainly in the north and northeast in terms of quantity and growth rate; (4) The secondary industries, the year-end resident population, the total energy consumption and the total investment in fixed assets are the natural capital stock consumption of Hainan Province. These findings can provide a scientific reference for the formulation of Hainan’s economic development and environmental protection policies to promote the coordinated and sustainable development of social, economic and environmental aspects of Hainan Province.

Due to the ecological and health hazards of volatile organic compounds (VOCs), the removal of industrial VOCs has become an important issue of increasing concern. In this work, we synthesized easy-processing ZIF-8/agarose composite porous carbon aerogels and investigated their toluene adsorption performance. Results indicated that carbon aerogels had large specific surface area, uniform microporous structure and high nitrogen content. The toluene adsorption capacity of carbon aerogel was 511.2 mg/g under RH50%, which was higher than that of commercial adsorbents and other MOFs with the same specific surface area. The adsorption mechanism of carbon aerogels was further studied via DFT method and was determined as pore-filling effect, π-π interaction and electron donor/acceptor interaction. In addition, carbon aerogels also showed high efficiency and recyclability which kept 70% adsorption capacity at ambient humidity and successfully regenerated after three cycles without obvious loss of adsorption capacity. Therefore, the high adsorption capacity and recyclability facilitate the synthesized aerogels become a promising adsorbent in VOCs adsorption field.

Understanding the variation characteristics and related determining factors of water requirements under climate change is crucial for crop production and agricultural water resource utilization. Therefore, in this study, the crop coefficient method and water balance model were employed to estimate the crop water requirement (CWR) and irrigation water requirement (IR) of winter wheat in the middle reaches of the Yarlung Zangbo River (YZR) and its two tributaries from 1981 to 2015. The impacts of different meteorological factors on the CWR and IR variations were explored using sensitivity and contribution analyses, and their determining factors were identified. The results showed that effective precipitation increased at a rate of 0.98 mm/year from 1981 to 2015. Meanwhile, the CWR and IR decreased significantly at −2.27 mm/year and −3.26 mm/year, respectively, with annual mean values of 620 mm and 499 mm, respectively. The CWR exhibited relatively high sensitivities to sunshine duration and wind speed, indicating that these factors were more likely to cause changes in the CWR, of which wind speed was the determining factor of the CWR variation because of its high sensitivity and substantial reduction. While increased temperature caused an increase in the CWR, its influence was relatively limited and was offset by the impact caused by other factors. Meanwhile, the determining factor of the IR variation was the CWR (contribution rate of 83.11%), and the contribution of effective precipitation was only 16.89%. Nevertheless, spatial differences existed in the CWR and IR variations and corresponding determining factors. As it is necessary to understand the impacts of climate change on water requirements for effective agricultural water resource utilization, the results of this study will provide valuable information for mitigating the impacts of climate change and improving agricultural water management in the YZR and its two tributaries.

Health risk of disinfection by-products (DBPs) makes the removal of trihalomethanes (THMs) precursors a great concern in water treatment. This study investigated the THMs precursors removal by coagulation with four coagulants, namely TiCl 4 , polymerized titanium chloride (PTC), Al 2 (SO 4 ) 3 , polymerized aluminum chloride (PAC), in silver nanoparticle-humic acid (AgNPs-HA) water treatment. Flocs formed during coagulation process were characterized using a laser diffraction particle-sizing device, and the residual dissolved organic matter (DOM) in coagulated water was characterized using three-dimensional Excitation and emission matrix (3DEEM) fluorescence spectroscopy. Results showed the reduction of THMs by a large margin through coagulation by the four coagulants, and CHCl 3 and CHBrCl 2 were observed as main species. Compared with conventional Al 2 (SO 4 ) 3 and PAC, TiC 4 and PTC achieved efficient AgNPs removal and were superior in terms of DOM removal with improved floc characteristics in terms of floc growth rate and floc size. Analysis of 3DEEM results suggested the fluorescent substance removal ability of TiCl 4 > PTC > Al 2 (SO 4 ) 3 > PAC, and the predominant fulvic acid-like DOM was removed to the largest extent through coagulation. Besides, anatase structured TiO 2 with efficient photocatalytic performance was finally recovered from TiCl 4 and PTC coagulated sludge. The atomic percentage of Ag-doped TiO 2 was TiO 1.82 Cl 0.25 Na 0.29 Ag 0.14 .

Climate change affects regional agricultural development, but a quantitative assessment of large-scale impacts remains difficult. Northwest China has experienced considerable climate change during the last 40 years, and this study uses GIS technology to evaluate the impacts of that change on the agricultural water balance. Results show that over the last 40 years the climate has transitioned from a warm-dry to a warm-wet pattern in the northwestern area of Northwest China, while exhibiting a pattern of increasing aridity in other parts of the region since the 1980s. Through analysis of the spatio-temporal distribution of agricultural water balance using water cycle models that include climatic, crop and cropland layers, we found that the climate warming in the northwestern area of the region has led to a notable reduction in the agricultural water deficit. This reduction, however, still cannot significantly alleviate the water deficit. Finally, we argue that to make agricultural development sustainable in this area, both hard and soft approaches are needed to bring about efficient use of the limited water resources.

China's grain-for-green policy of converting steep cultivated land to forest and grassland is one of the most important initiatives to develop its western inland regions. Using a multi-objective programming model, this study assessed the impacts of this policy in the upper reaches of the Yangtze River and the upper and middle reaches of the Yellow River. In addition to the strategic planning of converting cultivated land to forest and grassland and its associated impacts, three other scenarios were simulated. Results showed that impacts on grain supply at the national level were in the range of 2–3%. These results suggest that the proposed policy might not have a major impact on China's future grain supply and the world grain market. At the local level, however, impacts could be significant.