To investigate the effects of different vegetable growing regions and planting modes on soil quality,soils in high,medium and low altitude areas of Guizhou were respectively sampled under different vegetable efficient...To investigate the effects of different vegetable growing regions and planting modes on soil quality,soils in high,medium and low altitude areas of Guizhou were respectively sampled under different vegetable efficient planting modes,and the variations of soil microbial flora and enzyme activities were analyzed. The soil microbial count and total bacteria of the vegetable efficient cultivation mode were significantly higher than that of the control （traditional planting mode） in each planting area,and the microbial diversity index was also improved to varying de- grees.The soil phosphatase,catalase and urease activities of the vegetable efficient planting mode were higher than that of the control.The soil catalase and urease activities were higher than that of the control by 1.37-1.44 and 1.51-2.80 times. Application of vegetable efficient planting mode in different regions will help to im- prove the soil quality in a given period.展开更多
Corn is an important crop type in Henan, and its yield directly affects the income increase of farmers and agricultural development. In recent years, advanced technologies such as precision sowing and mechanized harve...Corn is an important crop type in Henan, and its yield directly affects the income increase of farmers and agricultural development. In recent years, advanced technologies such as precision sowing and mechanized harvesting have been widely used in the management of corn planting, which has significantly improved the efficiency of corn planting and promoted the expansion of corn yield. However, some people cant accurately grasp the management points of each growth period of corn, and there are still many problems in water and fertilizer management and pest control, which hinder the improvement of corn yield and quality. Faced with this situation, it is necessary to further study and popularize the efficient planting techniques of corn, help cultivators to fully grasp the management points of each growth period of corn, and promote the smooth realization of the goal of high yield and high quality of corn.展开更多
Split fertilization strategy is popularly adopted in rice to synchronize soil nitrogen(N) supply and crop N demand. Attention has been paid more on mid-season topdressing N, but limited on basal N. A clearer understan...Split fertilization strategy is popularly adopted in rice to synchronize soil nitrogen(N) supply and crop N demand. Attention has been paid more on mid-season topdressing N, but limited on basal N. A clearer understanding of the basal N fate under split fertilization is crucial for determining rational basal N split ratio to improve the yield and reduce the loss to environment. A two-year field experiment with two N rates of 150 and 300 kg Nha^(-1), two split ratios of basal N, 40% and 25%, and two rice varieties,Wuyunjing 23(japonica) and Y-liangyou 2(super hybrid indica), was conducted. Labelled ^(15) N urea was supplied in micro-plots as basal fertilizer to determine the plant uptake, translocation, soil residual, and loss of basal N fertilizer. The results showed that basal N absorbed by rice was only 1.6%–11.5% before tillering fertilization(8–10 d after transplanting), 6.5%–21.4% from tillering fertilization to panicle fertilization, and little(0.1%–4.4%) after panicle fertilization. The recovery efficiency of basal N for the entire rice growth stage was low and ranged from 18.7% to 24.8%, not significantly affected by cultivars or N treatments. Soil residual basal N accounted for 10.3%–36.4% and decreased with increasing total N rate and basal N ratio, regardless of variety and year. 43.8%–70.4% of basal N was lost into the environment based on the N balance. Basal N loss was significantly linearly positive related with the basal N rate and obviously enhanced by the increasing basal N ratio for both varieties in both 2012 and 2013. The N use efficiency and yield was significantly improved when decreasing the basal N ratio from 40% to 25%. The results indicated that the basal N ratio should be reduced, especially with limited N inputs, to improve the yield and reduce the N loss to the environment.展开更多
Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9...Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.展开更多
In this paper,we describe briefly an efficientculture procedure for micro-propagation of riceregeneration plants.The procedure consists ofthe following steps: 1.Preparation of materials Calli wereinduced from mature ...In this paper,we describe briefly an efficientculture procedure for micro-propagation of riceregeneration plants.The procedure consists ofthe following steps: 1.Preparation of materials Calli wereinduced from mature seeds of an indica rice lineG67 by culturing the husked and disinfectedseeds on agar medium,consisting of Nbasalelements,3％ sucrose,1000mg/L proline,and 32mg/L 2,4-D.After one month＇s in- duction culture and 3 wk subculture,compactand nodular calli were picked out and trans- ferred into liquid medium for suspension cul-tures.The liquid medium contained the same展开更多
Conservation agriculture practices are a crucial factor in mitigating and controlling erosion by water.To address water erosion estimates,most environmental models use the USLE,RUSLE,and MUSLE models.Management practi...Conservation agriculture practices are a crucial factor in mitigating and controlling erosion by water.To address water erosion estimates,most environmental models use the USLE,RUSLE,and MUSLE models.Management practices that affect soil erosion by modifying the flow pattern,such as contour farming,strip farming,or terracing,are represented within these models as a support practice(P)factor.However,due to the difficulty in accurately mapping the P-factor,many studies choose to ignore it,using only the default value P-factor 1 which represents the absence of sowing at the level or cultivation in strips.This study proposes a methodology that evaluates the current P-factor based on the angle between the crop row orientation and the elevation contour lines.The method was tested in four areas under soybean crop fields in southern Brazil,totaling 25 km^(2).The reason for choosing four areas is to select different characteristics of rural properties and topographic conditions.The ideal values of the P-factor are expected to be between 0.5 and 0.6;however,in our case,a P-factor greater than 0.8 was obtained in 60%of the area,indicating the low occurrence of contour farming reduces erosion rates.The results show that policymakers could potentially use this methodology(angle between the crop rows and contour lines)to run soil-erosion risk scenarios for a broader application of contour farming.This allows the P-factor to be quantified via a thematic map instead of assigning uniform P-factor values.With a detailed study of the P-factor on the slopes,there is a better understanding of where to target support practices to reduce erosion.展开更多
With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)wa...With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.展开更多
PREPARATION of HMW DNA (Megabase-size) is the basis for construction of genomic library with large DNA inserts such as bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC), and for long-range ph...PREPARATION of HMW DNA (Megabase-size) is the basis for construction of genomic library with large DNA inserts such as bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC), and for long-range physical mapping. It can also be used for the macro-study of repeat sequences. Since HMW DNA during preparation is inclined to be sheared physically and digested by internal nucleases, it is very difficult to prepare the HMW DNA. Initially, plant HMW DNA was prepared by embedding protoplasts in the low melting-point (LMP) agarose; however, it had several disadvantages: (ⅰ) Culture of protoplasts was time-consuming, costly and tedious. ( ⅱ ) It was only used successfully for limited展开更多
Since the discovery that nucleases of the bacterial CRISPR(clustered regularly interspaced palindromic repeat)-associated(Cas) system can be used as easily programmable tools for genome engineering,their application m...Since the discovery that nucleases of the bacterial CRISPR(clustered regularly interspaced palindromic repeat)-associated(Cas) system can be used as easily programmable tools for genome engineering,their application massively transformed different areas of plant biology. In this review, we assess the current state of their use for crop breeding to incorporate attractive new agronomical traits into specific cultivars of various crop plants. This can be achieved by the use of Cas9/12 nucleases for double-strand break induction,resulting in mutations by non-homologous recombinatr e-tion. Strategies for performing such experiments à from Rthe design of guide RNA to the use of different transformation technologies à are evaluated. Furtherweive-more, we sum up recent developments regarding the use of nuclease-deficient Cas9/12 proteins, as DNAbinding moieties for targeting different kinds of enzyme activities to specific sites within the genome. Progress in base deamination, transcriptional induction and transcriptional repression, as well as in imaging in plants, is also discussed. As different Cas9/12 enzymes are at hand, the simultaneous application of various enzyme activities, to multiple genomic sites, is now in reach to redirect plant metabolism in a multifunctional manner and pave the way for a new level of plant synthetic biology.展开更多
Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease...Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA(sgRNA)incorporating a target sequence(Li et al.,2019).A Cas9/sgRNA complex recognizes its target site in the genome,resulting in a mutation at that site.展开更多
Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit. The ...Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit. The effects of temperature and solvent concentration on yield, particle size distribution and purity were studied. The purity was higher, while the yield and particle size were lower and smaller, respectively, at higher temperature and solvent concentration. The solvent crystallization process efficiency was rated at 66-69% when carried out with 70-80% isopropyl alcohol at 20℃.展开更多
基金Supported by Key Project from National Spark Plan,China(2012GA820001)Special Project of Guizhou Provincial Science and Technology,China[Qiankehe Special Project(2011)6001)]+1 种基金"321"Efficient Planting Technique Integration and Demonstration of Vegetable from Technology Ombudsman,China[(2013)6061-1)]Guizhou Vegetable Industry Technique System Construction Program,China(GZCYTX2011-0101)~~
文摘To investigate the effects of different vegetable growing regions and planting modes on soil quality,soils in high,medium and low altitude areas of Guizhou were respectively sampled under different vegetable efficient planting modes,and the variations of soil microbial flora and enzyme activities were analyzed. The soil microbial count and total bacteria of the vegetable efficient cultivation mode were significantly higher than that of the control （traditional planting mode） in each planting area,and the microbial diversity index was also improved to varying de- grees.The soil phosphatase,catalase and urease activities of the vegetable efficient planting mode were higher than that of the control.The soil catalase and urease activities were higher than that of the control by 1.37-1.44 and 1.51-2.80 times. Application of vegetable efficient planting mode in different regions will help to im- prove the soil quality in a given period.
文摘Corn is an important crop type in Henan, and its yield directly affects the income increase of farmers and agricultural development. In recent years, advanced technologies such as precision sowing and mechanized harvesting have been widely used in the management of corn planting, which has significantly improved the efficiency of corn planting and promoted the expansion of corn yield. However, some people cant accurately grasp the management points of each growth period of corn, and there are still many problems in water and fertilizer management and pest control, which hinder the improvement of corn yield and quality. Faced with this situation, it is necessary to further study and popularize the efficient planting techniques of corn, help cultivators to fully grasp the management points of each growth period of corn, and promote the smooth realization of the goal of high yield and high quality of corn.
基金financially supported by the National Natural Science Foundation of China (No. 41171235)Jiangsu Agriculture Science and Technology Innovation Fund, China (No. CX(13)3040)the Special Fund for Environmental Research in the Public Interest, China (No. 201309035-7)
文摘Split fertilization strategy is popularly adopted in rice to synchronize soil nitrogen(N) supply and crop N demand. Attention has been paid more on mid-season topdressing N, but limited on basal N. A clearer understanding of the basal N fate under split fertilization is crucial for determining rational basal N split ratio to improve the yield and reduce the loss to environment. A two-year field experiment with two N rates of 150 and 300 kg Nha^(-1), two split ratios of basal N, 40% and 25%, and two rice varieties,Wuyunjing 23(japonica) and Y-liangyou 2(super hybrid indica), was conducted. Labelled ^(15) N urea was supplied in micro-plots as basal fertilizer to determine the plant uptake, translocation, soil residual, and loss of basal N fertilizer. The results showed that basal N absorbed by rice was only 1.6%–11.5% before tillering fertilization(8–10 d after transplanting), 6.5%–21.4% from tillering fertilization to panicle fertilization, and little(0.1%–4.4%) after panicle fertilization. The recovery efficiency of basal N for the entire rice growth stage was low and ranged from 18.7% to 24.8%, not significantly affected by cultivars or N treatments. Soil residual basal N accounted for 10.3%–36.4% and decreased with increasing total N rate and basal N ratio, regardless of variety and year. 43.8%–70.4% of basal N was lost into the environment based on the N balance. Basal N loss was significantly linearly positive related with the basal N rate and obviously enhanced by the increasing basal N ratio for both varieties in both 2012 and 2013. The N use efficiency and yield was significantly improved when decreasing the basal N ratio from 40% to 25%. The results indicated that the basal N ratio should be reduced, especially with limited N inputs, to improve the yield and reduce the N loss to the environment.
基金supported by the Beijing Scholars Program[BSP041]。
文摘Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.
文摘In this paper,we describe briefly an efficientculture procedure for micro-propagation of riceregeneration plants.The procedure consists ofthe following steps: 1.Preparation of materials Calli wereinduced from mature seeds of an indica rice lineG67 by culturing the husked and disinfectedseeds on agar medium,consisting of Nbasalelements,3％ sucrose,1000mg/L proline,and 32mg/L 2,4-D.After one month＇s in- duction culture and 3 wk subculture,compactand nodular calli were picked out and trans- ferred into liquid medium for suspension cul-tures.The liquid medium contained the same
基金This study was financed in part by the Coordenagao de Aper-feigoamento de Pessoal de Nivel Superior-Brasil(CAPES)-Finance Code 001,Federal University of Santa Maria(UFSM)and Conselho Nacional de Desenvolvimento Cientificóe Tecnologico-CNPq.
文摘Conservation agriculture practices are a crucial factor in mitigating and controlling erosion by water.To address water erosion estimates,most environmental models use the USLE,RUSLE,and MUSLE models.Management practices that affect soil erosion by modifying the flow pattern,such as contour farming,strip farming,or terracing,are represented within these models as a support practice(P)factor.However,due to the difficulty in accurately mapping the P-factor,many studies choose to ignore it,using only the default value P-factor 1 which represents the absence of sowing at the level or cultivation in strips.This study proposes a methodology that evaluates the current P-factor based on the angle between the crop row orientation and the elevation contour lines.The method was tested in four areas under soybean crop fields in southern Brazil,totaling 25 km^(2).The reason for choosing four areas is to select different characteristics of rural properties and topographic conditions.The ideal values of the P-factor are expected to be between 0.5 and 0.6;however,in our case,a P-factor greater than 0.8 was obtained in 60%of the area,indicating the low occurrence of contour farming reduces erosion rates.The results show that policymakers could potentially use this methodology(angle between the crop rows and contour lines)to run soil-erosion risk scenarios for a broader application of contour farming.This allows the P-factor to be quantified via a thematic map instead of assigning uniform P-factor values.With a detailed study of the P-factor on the slopes,there is a better understanding of where to target support practices to reduce erosion.
基金This work was supported in part by the National Natural Science Foundation of China(collaborating with EPSRC of UK)(Nos.51361130152 and EP/L001039/1)the National Science and Technology Support Program of China(No.2013BAA01B03)Research on Reactive Power Control and Comprehensive Evaluation Technique of Large Scale Integration of Wind/Photovoltaic Power Generation(No.NY71-14-035).
文摘With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.
文摘PREPARATION of HMW DNA (Megabase-size) is the basis for construction of genomic library with large DNA inserts such as bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC), and for long-range physical mapping. It can also be used for the macro-study of repeat sequences. Since HMW DNA during preparation is inclined to be sheared physically and digested by internal nucleases, it is very difficult to prepare the HMW DNA. Initially, plant HMW DNA was prepared by embedding protoplasts in the low melting-point (LMP) agarose; however, it had several disadvantages: (ⅰ) Culture of protoplasts was time-consuming, costly and tedious. ( ⅱ ) It was only used successfully for limited
基金Funding of our cooperative research by the German Federal Ministry of Education and Research (FKZ 031B0192)
文摘Since the discovery that nucleases of the bacterial CRISPR(clustered regularly interspaced palindromic repeat)-associated(Cas) system can be used as easily programmable tools for genome engineering,their application massively transformed different areas of plant biology. In this review, we assess the current state of their use for crop breeding to incorporate attractive new agronomical traits into specific cultivars of various crop plants. This can be achieved by the use of Cas9/12 nucleases for double-strand break induction,resulting in mutations by non-homologous recombinatr e-tion. Strategies for performing such experiments à from Rthe design of guide RNA to the use of different transformation technologies à are evaluated. Furtherweive-more, we sum up recent developments regarding the use of nuclease-deficient Cas9/12 proteins, as DNAbinding moieties for targeting different kinds of enzyme activities to specific sites within the genome. Progress in base deamination, transcriptional induction and transcriptional repression, as well as in imaging in plants, is also discussed. As different Cas9/12 enzymes are at hand, the simultaneous application of various enzyme activities, to multiple genomic sites, is now in reach to redirect plant metabolism in a multifunctional manner and pave the way for a new level of plant synthetic biology.
基金grants from the National Natural Science Foundation of China (91435203 and 31991222)the Major Program of Guangdong Basic and Applied Basic Research (2019B030302006)。
文摘Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA(sgRNA)incorporating a target sequence(Li et al.,2019).A Cas9/sgRNA complex recognizes its target site in the genome,resulting in a mutation at that site.
文摘Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit. The effects of temperature and solvent concentration on yield, particle size distribution and purity were studied. The purity was higher, while the yield and particle size were lower and smaller, respectively, at higher temperature and solvent concentration. The solvent crystallization process efficiency was rated at 66-69% when carried out with 70-80% isopropyl alcohol at 20℃.
