This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23...This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23 and 75） were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design （BBD） to optimize the liquid fermentation conditions and obtain the maximum cell dry weight （CDW） yield. Opti-mal parameters were obtained under the following experimental condi-tions：temperature of 28＆#176;C, potato dextrose agar （PDA） liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I-IV, flavonoids or polysaccharides. Iso-lation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research.展开更多
Sending-end multi-terminal high-voltage direct current(MT-HVDC)systems are well-suited for large-scale renewable energy collection and transmission.However,the capacity planning for converter stations(CSs),which is di...Sending-end multi-terminal high-voltage direct current(MT-HVDC)systems are well-suited for large-scale renewable energy collection and transmission.However,the capacity planning for converter stations(CSs),which is directly correlated with their ability to convert renewable energy,remains a critical issue.In this paper,an optimal capacity planning method for CSs is proposed to maximize the converted energy(CE).The proposed method considers the uncertainties of photovoltaic(PV)generation and derives analytical formulas for stochastic CEs.The equal incremental rate(EIR)principle is employed to calculate the optimal capacity planning scheme,and then a general guideline for the capacity planning in stochastic scenarios is presented.Case studies are conducted to validate the effectiveness of the proposed method and the proposed guideline.The results demonstrate that the proposed method converts more renewable energy than the deterministic method.展开更多
Ratoon is the stub or root of a perennial plant that is commonly retained after harvest to produce a following crop.This paper presents a review of ratoon cotton in relation to a broader framework that has been examin...Ratoon is the stub or root of a perennial plant that is commonly retained after harvest to produce a following crop.This paper presents a review of ratoon cotton in relation to a broader framework that has been examining perennialization of agriculture for the benefit of ecology and economy.Cotton is botanically indeterminate,but has been treated as an annual after domestication,yet the habit of perenniality is retained and the plants begin to resprout after the first harvest.In some cropping systems,this tendency is exploited using the“ratooning”practice(i.e.growing one or more crops on the rootstock of the first).Ratooning has declined for various reasons such as an increase in the prevalence of pests and diseases and overwintering risk.However,ratooning has many benefits such as no annual tillage before sowing,a well-established root system,and high yield.The three methods of ratooning offer flexibility to balance the environmental and economic benefits in agriculture.The greatest environmental benefits arise from perennial ratoon cropping of semi-wild cotton,and the greatest economic benefit is obtained from biannually cropping modern annual cultivars.However,an optimum solution would be provided by perennial cropping annual cultivars.To realize both environmental and economic benefits,research is needed in the following main areas:preventing the buildup of pests and diseases,breeding the most suitable cotton cultivars for ratooning,and developing light and simplified cultivation(LSC)systems for ratoon cultivation.展开更多
基金supported by grants from the Key Program of Natural Science Foundation of State(Grant No.81274010)Heilongjiang province outstanding youth fund(Grant No.JC201101)Talent fund of Heilongjiang University of Chinese Medicine Talent Fund
文摘This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23 and 75） were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design （BBD） to optimize the liquid fermentation conditions and obtain the maximum cell dry weight （CDW） yield. Opti-mal parameters were obtained under the following experimental condi-tions：temperature of 28＆#176;C, potato dextrose agar （PDA） liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I-IV, flavonoids or polysaccharides. Iso-lation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research.
基金supported by National Natural Science Foundation of China(No.52077045)Shenzhen-Hong Kong-Macao Science and Technology Program(category C)(No.SGDX20220530111403026).
文摘Sending-end multi-terminal high-voltage direct current(MT-HVDC)systems are well-suited for large-scale renewable energy collection and transmission.However,the capacity planning for converter stations(CSs),which is directly correlated with their ability to convert renewable energy,remains a critical issue.In this paper,an optimal capacity planning method for CSs is proposed to maximize the converted energy(CE).The proposed method considers the uncertainties of photovoltaic(PV)generation and derives analytical formulas for stochastic CEs.The equal incremental rate(EIR)principle is employed to calculate the optimal capacity planning scheme,and then a general guideline for the capacity planning in stochastic scenarios is presented.Case studies are conducted to validate the effectiveness of the proposed method and the proposed guideline.The results demonstrate that the proposed method converts more renewable energy than the deterministic method.
基金This work was supported by the National Natural Science Foundation of China[31571600]National Key R&D Program of China[2016YFD0101413].
文摘Ratoon is the stub or root of a perennial plant that is commonly retained after harvest to produce a following crop.This paper presents a review of ratoon cotton in relation to a broader framework that has been examining perennialization of agriculture for the benefit of ecology and economy.Cotton is botanically indeterminate,but has been treated as an annual after domestication,yet the habit of perenniality is retained and the plants begin to resprout after the first harvest.In some cropping systems,this tendency is exploited using the“ratooning”practice(i.e.growing one or more crops on the rootstock of the first).Ratooning has declined for various reasons such as an increase in the prevalence of pests and diseases and overwintering risk.However,ratooning has many benefits such as no annual tillage before sowing,a well-established root system,and high yield.The three methods of ratooning offer flexibility to balance the environmental and economic benefits in agriculture.The greatest environmental benefits arise from perennial ratoon cropping of semi-wild cotton,and the greatest economic benefit is obtained from biannually cropping modern annual cultivars.However,an optimum solution would be provided by perennial cropping annual cultivars.To realize both environmental and economic benefits,research is needed in the following main areas:preventing the buildup of pests and diseases,breeding the most suitable cotton cultivars for ratooning,and developing light and simplified cultivation(LSC)systems for ratoon cultivation.
