[Objective] This study was conducted to provide certain theoretical reference for the comprehensive evaluation and breeding of new fresh waxy corn vari- eties. [Method] With 5 good fresh waxy corn varieties as experim...[Objective] This study was conducted to provide certain theoretical reference for the comprehensive evaluation and breeding of new fresh waxy corn vari- eties. [Method] With 5 good fresh waxy corn varieties as experimental materials, correlation analysis and principal component anatysis were performed on 13 agronomic traits, i.e., plant height, ear position, ear weight, ear diameter, axis diameter, ear length, bald tip length, ear row number, number of grains per row, 100-kernel weight, fresh ear yield, tassel length, and tassel branch number. [Result] The principal component analysis performed to the 13 agronomic traits showed that the first three principal components, i.e., the fresh ear yield factors, the tassel factors and the bald top factors, had an accumulative contribution rate over 87.2767%, and could basically represent the genetic information represented by the 13 traits. The first principal component is the main index for the selection and evaluation of good corn varieties which should have large ear, large ear diameter but small axis diameter, i.e., longer grains, larger number of grains per ear, higher, 100-grain weight and higher plant height. As to the second principal component, the plants of fresh corn varieties are best to have longer tassel and not too many branches, and under the premise of ensuring enough pollen for the female spike, the varieties with fewer tassel branches shoud be selected as far as possible. From the point of the third principal component, bald tip length affects the marketing quality of fresh corn, and during fariety evaluation and breeding, the bald top length should be control at the Iowest standard. [Conclusion] The fresh ear yield of corn is in close positive correlation with ear weight, 100-grain weight, ear diameter, number of grains per row and ear length, and plant height also affects fresh ear yield.展开更多
This study analyzed the tartary buckwheat recorded in the books Catalogue of Crop Germplasm Resources in Shanxi Province and Catalogue of Chinese Buckwheat Germplasm Resources by Excel 2003 and DPS 7.5 from the aspect...This study analyzed the tartary buckwheat recorded in the books Catalogue of Crop Germplasm Resources in Shanxi Province and Catalogue of Chinese Buckwheat Germplasm Resources by Excel 2003 and DPS 7.5 from the aspects of distribution areas,main agronomic traits and nutritional components,so as to lay a foundation for the selection of excellent buckwheat germplasm resources and improvement of buckwheat varieties.The results showed that different buckwheat varieties vary in plant height,node number of the main stem,grain weight per plant,grain weight per plant and kilo-grain weight.Compared with the national average values,buckwheat in Shanxi is higher in protein and fat,but lower in vitamin E and vitamin PP;it is rich in Ca,Mg,Cu,P,Se,Fe,Mn and Zn;and it contains 18 amino acids with the content of glutamic acid being the highest and the content of tryptophane being the lowest.After analyzing and classifying the tartary buckwheat germplasm resources recorded in Catalogue of Grop Germplasm Resources in Shanxi Province and Catalogue of Chinese Buckwheat Germplasm Resources,breeders could breed new varieties with high yield and quality and strong stress resistance by crossbreeding with these germplasm resources.展开更多
Objective] This study was conducted to investigate the main factors affect-ing the lodging resistance of plateau japonica rice. [Method] Twenty agronomic traits related to lodging resistance of plateau japonica rice w...Objective] This study was conducted to investigate the main factors affect-ing the lodging resistance of plateau japonica rice. [Method] Twenty agronomic traits related to lodging resistance of plateau japonica rice were analyzed by principal component analysis and correlation analysis among 26 varieties/lines of plateau japonica rice. [Result] The lodging resistance of the 26 varieties/lines had great dif-ference among different agronomic traits. Plant height, and wal thickness of the 4th, 3rd and 2nd internodes under the panicle had the most important influence on lodging resistance, while the diameter of the 3rd, 2nd, 4th, 1st nodes under the panicle, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st internode under the panicle had less influence. The other nine agronomic traits of rice culm did not affect or indirectly affected lodging resistance through above-mentioned agro-nomic traits. Lodging resistance had significant correlations with plant height, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st, 2nd, 3rd and 4th internodes under the panicle and diameter of the 1st, 2nd, 3rd and 4th node sunder the panicle, had insignificant correlations with panicle length, panicle weight, length of the 1st and 2nd internodes under the panicle, diameter of the 1st, 2nd, 3rd and 4th internodes under the panicle, diameter of the 5th node under the panicle. [Conclu-sion] More attention should be paid to the main factors affecting lodging resistance in breeding to improve lodging resistance of plateau japonica rice.展开更多
The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (G...The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (GC-NPD); to select an appropriate solvent system; to conduct a comparison of sonication and shaking extractions; and to select an appropriate procedure for extracting organophosphorus pesticides from soils. Procedure I consisted of n-hexane or petroleum ether together with acetone used as solvents, while Procedure contained several solvents including acetone, methanol, dichloromethane, and n-hexane or petroleum ether. Experimental results indicated that a mixture of petroleum ether/acetone (2:1, v/v) could be used in place of n-hexane/acetone (2:1, v/v) as it was a less expensive solvent system. In addition, shaking under a water bath at 20 °C was more effective than sonication. Also, Procedure I was more effective, safer, and more timesaving than Procedure Procedure I was applied to three soil types of different organic matter content, with recoveries of the OPPs from the yellow-brown soils, which had a higher organic matter content, being lower than those from the yellow and red soils.展开更多
Objective:The aim of our study was to estimate the cost of colorectal cancer screening and to provide evidence for the cost control of colorectal cancer screening among general population in rural area of China.Method...Objective:The aim of our study was to estimate the cost of colorectal cancer screening and to provide evidence for the cost control of colorectal cancer screening among general population in rural area of China.Methods:We determined the net cost for colorectal cancer mass-screening in Jiashan County,and evaluated the cost-benefit and cost effectiveness.Results:The compliance rate of primary screening and intensive screening were 84.6% and 78.7%,respectively.In primary screening,the average cost for each individual was 27.2 yuan,and the average cost for identifying one high-risk individual was 180.5 yuan.The mean cost to diagnose one colorectal cancer patient was 42963.3 yuan.As for identification of adenoma,the average cost for each case was 4384.0 yuan.Based on the calculation,the average cost of reducing one colorectal cancer patient was 12768 yuan by conducting the mass-screening protocol.Conclusion:It was beneficial to do the cost-benefit analysis of colorectal cancer screening in area of high incidence.Based on the results of cost-benefit analysis,more efforts should be made to reduce the cost and to improve the efficiency of the colorectal cancer screening.展开更多
Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents ...Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).展开更多
The objectives of this study were to demonstrate ethno-scientific elicitation techniques in retrieving indigenous knowledge at village-level, and to document the indigenous soil classification systems of different eth...The objectives of this study were to demonstrate ethno-scientific elicitation techniques in retrieving indigenous knowledge at village-level, and to document the indigenous soil classification systems of different ethnic groups in Luang Prabang province in the Lao PDR. The study area comprised three villages – Nambo, Huaymaha and Thapo, in the Phonxay district of Luang Prabang province. Three ethnic groups were covered by the study – Hmong, Khmu and Lao Loum. All three ethnic groups used soil color as main criteria for soil classification. However, even within the same ethnic group, sometimes different villages have differences in the way they classify soils; this was apparent for the Hmong ethnic group in the villages of Huaymaha and Nambo. A significant difference of the Lao Loum ethnic group from the other two, was the emphasis used in classifying soil types according to their water holding capabilities. In contrast, the Khmu and Hmong classified many soil types in relation to their rock content (‘with rock’ or ‘pure rock’ sometimesbeing used). The results of the study suggest that the ethnic groups classify the soils in relation to their potential for different types of agricultural production.展开更多
F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main ch...F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main changing period of agronomic traits. Compared with the comparative heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (97.92%), internode length (100%) and stem girth (58.33%) were larger, these of total nitrogen (83.33%), protein (79.17%), nicotine (79.17%) and potassium (95.83%) in upper leaves were larger, these of total sugar (64.58%), total nitrogen (68.75%), protein (72.92%) and nicotine (64.58%) in middle leaves were larger, and in lower leaves, except that the proportion of chlorine was smaller (12.50%), the proportions of other chemical components all exceeded 40%. Compared with average heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (54.17%), leaf width (43.75%), stem girth (43.75%) and internode length (72.92%) were larger, these of total sugar (47.92%) and reducing sugar (54.17%) in upper leaves were larger, these of all the chemical components in middle leaves exceeded 30%, and these of all the chemical components in lower leaves were in the range of 27.08%-41.67%. Compared with heterobeltiosis, among the proportions of combinations showing positive comparative heterosis at the significant level, that of the internode length (60.42%) was larger, these of chemical components in upper leaves were in the range of 8.33%-29.17%, these of chemical components in middle leaves were in the range of 20.83%-39.58%, and these of chemical components in lower leaves were in the range of 16.67%-35.42%. It was indicated that rational effective control of water and fertilizer in this sensitive period could significantly enhance heterosis.展开更多
The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from t...The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from the land utilization perspective, involving changes in grain production per unit area, multi-cropping index, and adjustment of agricultural structure. Compared with the record values, different research methodologies are used to analyze the po- tential of above three components. The results indicate that grain production potential of 65.68×109kg was unexploited in 2006, in which 45.8×109kg came from the restructuring in agriculture. So we can infer that the reduction of grain production in China could be primarily attributed to agricultural restructuring in recent years. So the productive poten- tial can be fully restored by increasing agricultural investment, or recovering agricultural structure in favorable condi- tions. So we can say that China’s current condition of food security is good.展开更多
Human activity and urbanization result in urban-rural environmental gradients. Understanding effect of the gradients on soil properties is necessary for management of the soils around urban areas. In this study, soil ...Human activity and urbanization result in urban-rural environmental gradients. Understanding effect of the gradients on soil properties is necessary for management of the soils around urban areas. In this study, soil quality of some vegetable fields was characterized along an urban-rural gradient in Shaoxing County, Zhejiang Province. Fifteen soil physical and chemical properties were evaluated by using principal component analysis.Results showed that there was a great variation in the soil quality along the gradient. From rural to urban zones, soil organic matter, water-stable aggregates, cation exchangeable capacity (CEC), total N and P, and available K increased, whereas soil pH value decreased. In addition, Pb, Cu, Ni, Co, Zn and Cr in the soils tended to be accumulated toward the urban zone. Sequential chemical extraction showed that mobility of all the heavy metals in the soils tended to increase from the rural to the urban zones. The variation of soil properties accounted for by the first principal component was significantly explained by the difference in application rates of municipal wastes.展开更多
This paper reports a generation and composition analysis of household solid waste in Mexico, using as a reference the characterization study performed in two communities, one urban and one rural. Data obtained are fun...This paper reports a generation and composition analysis of household solid waste in Mexico, using as a reference the characterization study performed in two communities, one urban and one rural. Data obtained are fundamental parameters for the planning of urban solid waste management systems in Mexico, complying this way with the established policy in the National Program for Waste Management and Prevention 2009-2012. The study was carried out during five days and two main parameters were assessed: (1) the daily generation rate per person and (2) the waste composition. The per capita waste generation was 0.958 kg for the urban community and 0.631 kg for the rural. The results showed that the mean composition of waste from both locations was statistically similar (a = 0.05). In both locations the most important contribution was the fraction of food waste. In both locations more than 60% of the waste is potentially recyclable. The results of this study will be used by the municipal waste authorities in order to establish an integrated waste management plan.展开更多
The study, conducted in the Canton Erd6-Pala Chad, aims to i) list the different cultural practices, ii) study their impact on the vegetation and iii) determine the methods of co-management of these cultural practi...The study, conducted in the Canton Erd6-Pala Chad, aims to i) list the different cultural practices, ii) study their impact on the vegetation and iii) determine the methods of co-management of these cultural practices. The surveys were realized on 50 households in the village and phytosociological plants in corn, millet, cotton and peanuts cultures. The data analysis by statgraphic and Excel and Principal Component Analysis (PCA) showed that maize production (1,200 kg/ha) ranked first at the expense of cotton (640 kg/ha). They negatively affect climate change (temperature increase (26%), rain drop (20%), land reclamation (18%) and flooding (12%)). Surveys of vegetation on three acres cotton fields (76.17%), millet (81.06%), corn (80.32%) and groundnut (83.56%) showed that there is no significant difference (P = 0.05) on the specific contribution of wood of different types of farming practices. Adventists species herbacious like Thelepogon elegans (27.84%), Hyptis spicigera (19.31%), Teramnus labialis (15.86%) have most important contributions in specific cultures. Methods of crop treatments have a destructive impact on the environment and the loss of biodiversity and the invasion of crops by adventists. Co-management, crop rotation, association of cultures, community forest management, agroforestry and training farmers in the use of inputs will reduce the potential risks of farming practices.展开更多
Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soy...Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soybean (Glycine max L. Merill) growing area located in Northeast China, was evaluated using soil quality index (SQI) methods. Each SQI was computed using a minimum data set (MDS) selected using principal components analysis (PCA) as a data reduction technique. Eight MDS indicators were selected from 20 physical and chemical soil measurements. The MDS accounted for 74.9% of the total variance in the total data set (TDS). The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods. The results showed that SQI values correlated well with soybean yield (r = 0.658**) when indicators in MDS were weighted by the regression coefficient computed for each yield and index. Stepwise regression between yield and principal components (PCs) indicated that available boron (AvB), available phosphorus (AvP), available potassium (AvK), available iron (AvFe) and texture were the main factors limiting soybean yield. The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.展开更多
Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.T...Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.These characteristics enable them to have a range of biological activities and promising pharmaceutical and agricultural applications.Here,we present a practical strategy for the chemical synthesis of cyclotides through the intramolecular ligation of fully unprotected peptide O-esters.This strategy involves the mild Fmoc solid-phase peptide synthesis of the peptide O-ester backbone,the head-to-tail cyclization of the cyclotide backbone by native chemical ligation,and the oxidative refolding to yield the natural knot protein.The simplicity and high efficiency of the strategy can be employed in the synthesis of artificial cyclotides for pharmaceutical applications.展开更多
文摘[Objective] This study was conducted to provide certain theoretical reference for the comprehensive evaluation and breeding of new fresh waxy corn vari- eties. [Method] With 5 good fresh waxy corn varieties as experimental materials, correlation analysis and principal component anatysis were performed on 13 agronomic traits, i.e., plant height, ear position, ear weight, ear diameter, axis diameter, ear length, bald tip length, ear row number, number of grains per row, 100-kernel weight, fresh ear yield, tassel length, and tassel branch number. [Result] The principal component analysis performed to the 13 agronomic traits showed that the first three principal components, i.e., the fresh ear yield factors, the tassel factors and the bald top factors, had an accumulative contribution rate over 87.2767%, and could basically represent the genetic information represented by the 13 traits. The first principal component is the main index for the selection and evaluation of good corn varieties which should have large ear, large ear diameter but small axis diameter, i.e., longer grains, larger number of grains per ear, higher, 100-grain weight and higher plant height. As to the second principal component, the plants of fresh corn varieties are best to have longer tassel and not too many branches, and under the premise of ensuring enough pollen for the female spike, the varieties with fewer tassel branches shoud be selected as far as possible. From the point of the third principal component, bald tip length affects the marketing quality of fresh corn, and during fariety evaluation and breeding, the bald top length should be control at the Iowest standard. [Conclusion] The fresh ear yield of corn is in close positive correlation with ear weight, 100-grain weight, ear diameter, number of grains per row and ear length, and plant height also affects fresh ear yield.
文摘This study analyzed the tartary buckwheat recorded in the books Catalogue of Crop Germplasm Resources in Shanxi Province and Catalogue of Chinese Buckwheat Germplasm Resources by Excel 2003 and DPS 7.5 from the aspects of distribution areas,main agronomic traits and nutritional components,so as to lay a foundation for the selection of excellent buckwheat germplasm resources and improvement of buckwheat varieties.The results showed that different buckwheat varieties vary in plant height,node number of the main stem,grain weight per plant,grain weight per plant and kilo-grain weight.Compared with the national average values,buckwheat in Shanxi is higher in protein and fat,but lower in vitamin E and vitamin PP;it is rich in Ca,Mg,Cu,P,Se,Fe,Mn and Zn;and it contains 18 amino acids with the content of glutamic acid being the highest and the content of tryptophane being the lowest.After analyzing and classifying the tartary buckwheat germplasm resources recorded in Catalogue of Grop Germplasm Resources in Shanxi Province and Catalogue of Chinese Buckwheat Germplasm Resources,breeders could breed new varieties with high yield and quality and strong stress resistance by crossbreeding with these germplasm resources.
基金Supported by Program for the Breeding and Industrial Development of Conventional Rice Varieties(2010BB013)Training Plan of Technological Innovation Talents of Yunnan Province(2010CI075)~~
文摘Objective] This study was conducted to investigate the main factors affect-ing the lodging resistance of plateau japonica rice. [Method] Twenty agronomic traits related to lodging resistance of plateau japonica rice were analyzed by principal component analysis and correlation analysis among 26 varieties/lines of plateau japonica rice. [Result] The lodging resistance of the 26 varieties/lines had great dif-ference among different agronomic traits. Plant height, and wal thickness of the 4th, 3rd and 2nd internodes under the panicle had the most important influence on lodging resistance, while the diameter of the 3rd, 2nd, 4th, 1st nodes under the panicle, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st internode under the panicle had less influence. The other nine agronomic traits of rice culm did not affect or indirectly affected lodging resistance through above-mentioned agro-nomic traits. Lodging resistance had significant correlations with plant height, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st, 2nd, 3rd and 4th internodes under the panicle and diameter of the 1st, 2nd, 3rd and 4th node sunder the panicle, had insignificant correlations with panicle length, panicle weight, length of the 1st and 2nd internodes under the panicle, diameter of the 1st, 2nd, 3rd and 4th internodes under the panicle, diameter of the 5th node under the panicle. [Conclu-sion] More attention should be paid to the main factors affecting lodging resistance in breeding to improve lodging resistance of plateau japonica rice.
基金1Project supported by the Outstanding Youth Fund of the National Natural Science Foundation of China (No. 40325001),the National Key Basic Research Support Foundation of China (Nos. 2002CB415203 and 2002CB410805) and the Knowl-edge Innovation Program of
文摘The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (GC-NPD); to select an appropriate solvent system; to conduct a comparison of sonication and shaking extractions; and to select an appropriate procedure for extracting organophosphorus pesticides from soils. Procedure I consisted of n-hexane or petroleum ether together with acetone used as solvents, while Procedure contained several solvents including acetone, methanol, dichloromethane, and n-hexane or petroleum ether. Experimental results indicated that a mixture of petroleum ether/acetone (2:1, v/v) could be used in place of n-hexane/acetone (2:1, v/v) as it was a less expensive solvent system. In addition, shaking under a water bath at 20 °C was more effective than sonication. Also, Procedure I was more effective, safer, and more timesaving than Procedure Procedure I was applied to three soil types of different organic matter content, with recoveries of the OPPs from the yellow-brown soils, which had a higher organic matter content, being lower than those from the yellow and red soils.
文摘Objective:The aim of our study was to estimate the cost of colorectal cancer screening and to provide evidence for the cost control of colorectal cancer screening among general population in rural area of China.Methods:We determined the net cost for colorectal cancer mass-screening in Jiashan County,and evaluated the cost-benefit and cost effectiveness.Results:The compliance rate of primary screening and intensive screening were 84.6% and 78.7%,respectively.In primary screening,the average cost for each individual was 27.2 yuan,and the average cost for identifying one high-risk individual was 180.5 yuan.The mean cost to diagnose one colorectal cancer patient was 42963.3 yuan.As for identification of adenoma,the average cost for each case was 4384.0 yuan.Based on the calculation,the average cost of reducing one colorectal cancer patient was 12768 yuan by conducting the mass-screening protocol.Conclusion:It was beneficial to do the cost-benefit analysis of colorectal cancer screening in area of high incidence.Based on the results of cost-benefit analysis,more efforts should be made to reduce the cost and to improve the efficiency of the colorectal cancer screening.
基金Supported by the National High Technology Research and Development Program of China (2007AA03Z456)the National Natural Science Foundation of China (20776119, 21076169 and 31000019)+5 种基金the Xi’an Research and Development Program(NC08005, YF07078)the Scientific Research Program of Shaanxi Provincial Department of Education,China(08JK452,08JK453,JG08181,2010JC21,2010JS107,2010JS108, 2010JK876 and 2010JS109)Shaanxi Provincial Scientific Technology Research and Development Program (2007K06-03, 2010JQ2012, SJ08B03)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20096101120023, 20096101110014)NWU Graduate Innovation and Creativity Funds (08YSY17)Shaanxi Key Subject Program, China
文摘Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).
文摘The objectives of this study were to demonstrate ethno-scientific elicitation techniques in retrieving indigenous knowledge at village-level, and to document the indigenous soil classification systems of different ethnic groups in Luang Prabang province in the Lao PDR. The study area comprised three villages – Nambo, Huaymaha and Thapo, in the Phonxay district of Luang Prabang province. Three ethnic groups were covered by the study – Hmong, Khmu and Lao Loum. All three ethnic groups used soil color as main criteria for soil classification. However, even within the same ethnic group, sometimes different villages have differences in the way they classify soils; this was apparent for the Hmong ethnic group in the villages of Huaymaha and Nambo. A significant difference of the Lao Loum ethnic group from the other two, was the emphasis used in classifying soil types according to their water holding capabilities. In contrast, the Khmu and Hmong classified many soil types in relation to their rock content (‘with rock’ or ‘pure rock’ sometimesbeing used). The results of the study suggest that the ethnic groups classify the soils in relation to their potential for different types of agricultural production.
基金Supported by Key Project of China Tobacco Corporation in 2014(110201402003)~~
文摘F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main changing period of agronomic traits. Compared with the comparative heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (97.92%), internode length (100%) and stem girth (58.33%) were larger, these of total nitrogen (83.33%), protein (79.17%), nicotine (79.17%) and potassium (95.83%) in upper leaves were larger, these of total sugar (64.58%), total nitrogen (68.75%), protein (72.92%) and nicotine (64.58%) in middle leaves were larger, and in lower leaves, except that the proportion of chlorine was smaller (12.50%), the proportions of other chemical components all exceeded 40%. Compared with average heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (54.17%), leaf width (43.75%), stem girth (43.75%) and internode length (72.92%) were larger, these of total sugar (47.92%) and reducing sugar (54.17%) in upper leaves were larger, these of all the chemical components in middle leaves exceeded 30%, and these of all the chemical components in lower leaves were in the range of 27.08%-41.67%. Compared with heterobeltiosis, among the proportions of combinations showing positive comparative heterosis at the significant level, that of the internode length (60.42%) was larger, these of chemical components in upper leaves were in the range of 8.33%-29.17%, these of chemical components in middle leaves were in the range of 20.83%-39.58%, and these of chemical components in lower leaves were in the range of 16.67%-35.42%. It was indicated that rational effective control of water and fertilizer in this sensitive period could significantly enhance heterosis.
基金Under the auspices of National Key Technologies R&D Program of China (No. 2006BAB15B02)National Natural Science Foundation of China (No. 40671009)
文摘The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from the land utilization perspective, involving changes in grain production per unit area, multi-cropping index, and adjustment of agricultural structure. Compared with the record values, different research methodologies are used to analyze the po- tential of above three components. The results indicate that grain production potential of 65.68×109kg was unexploited in 2006, in which 45.8×109kg came from the restructuring in agriculture. So we can infer that the reduction of grain production in China could be primarily attributed to agricultural restructuring in recent years. So the productive poten- tial can be fully restored by increasing agricultural investment, or recovering agricultural structure in favorable condi- tions. So we can say that China’s current condition of food security is good.
基金Project supported by the National Key Basic Research Support Foundation (NKBRSF) of China (No. 1999011809).
文摘Human activity and urbanization result in urban-rural environmental gradients. Understanding effect of the gradients on soil properties is necessary for management of the soils around urban areas. In this study, soil quality of some vegetable fields was characterized along an urban-rural gradient in Shaoxing County, Zhejiang Province. Fifteen soil physical and chemical properties were evaluated by using principal component analysis.Results showed that there was a great variation in the soil quality along the gradient. From rural to urban zones, soil organic matter, water-stable aggregates, cation exchangeable capacity (CEC), total N and P, and available K increased, whereas soil pH value decreased. In addition, Pb, Cu, Ni, Co, Zn and Cr in the soils tended to be accumulated toward the urban zone. Sequential chemical extraction showed that mobility of all the heavy metals in the soils tended to increase from the rural to the urban zones. The variation of soil properties accounted for by the first principal component was significantly explained by the difference in application rates of municipal wastes.
文摘This paper reports a generation and composition analysis of household solid waste in Mexico, using as a reference the characterization study performed in two communities, one urban and one rural. Data obtained are fundamental parameters for the planning of urban solid waste management systems in Mexico, complying this way with the established policy in the National Program for Waste Management and Prevention 2009-2012. The study was carried out during five days and two main parameters were assessed: (1) the daily generation rate per person and (2) the waste composition. The per capita waste generation was 0.958 kg for the urban community and 0.631 kg for the rural. The results showed that the mean composition of waste from both locations was statistically similar (a = 0.05). In both locations the most important contribution was the fraction of food waste. In both locations more than 60% of the waste is potentially recyclable. The results of this study will be used by the municipal waste authorities in order to establish an integrated waste management plan.
文摘The study, conducted in the Canton Erd6-Pala Chad, aims to i) list the different cultural practices, ii) study their impact on the vegetation and iii) determine the methods of co-management of these cultural practices. The surveys were realized on 50 households in the village and phytosociological plants in corn, millet, cotton and peanuts cultures. The data analysis by statgraphic and Excel and Principal Component Analysis (PCA) showed that maize production (1,200 kg/ha) ranked first at the expense of cotton (640 kg/ha). They negatively affect climate change (temperature increase (26%), rain drop (20%), land reclamation (18%) and flooding (12%)). Surveys of vegetation on three acres cotton fields (76.17%), millet (81.06%), corn (80.32%) and groundnut (83.56%) showed that there is no significant difference (P = 0.05) on the specific contribution of wood of different types of farming practices. Adventists species herbacious like Thelepogon elegans (27.84%), Hyptis spicigera (19.31%), Teramnus labialis (15.86%) have most important contributions in specific cultures. Methods of crop treatments have a destructive impact on the environment and the loss of biodiversity and the invasion of crops by adventists. Co-management, crop rotation, association of cultures, community forest management, agroforestry and training farmers in the use of inputs will reduce the potential risks of farming practices.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences(No.KSCX1-YW-09-02)the National Basic Research Program of China(No.2013CB127401)+1 种基金the National Natural Science Foundation of China(No.41271309)the International Plant Nutrition Institute (IPNI) China Program
文摘Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soybean (Glycine max L. Merill) growing area located in Northeast China, was evaluated using soil quality index (SQI) methods. Each SQI was computed using a minimum data set (MDS) selected using principal components analysis (PCA) as a data reduction technique. Eight MDS indicators were selected from 20 physical and chemical soil measurements. The MDS accounted for 74.9% of the total variance in the total data set (TDS). The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods. The results showed that SQI values correlated well with soybean yield (r = 0.658**) when indicators in MDS were weighted by the regression coefficient computed for each yield and index. Stepwise regression between yield and principal components (PCs) indicated that available boron (AvB), available phosphorus (AvP), available potassium (AvK), available iron (AvFe) and texture were the main factors limiting soybean yield. The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.
基金supported by the National Natural Science Foundation of China(20932006,91013007)the National Basic Research Program of China(973 Program)(2011CB965300)
文摘Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.These characteristics enable them to have a range of biological activities and promising pharmaceutical and agricultural applications.Here,we present a practical strategy for the chemical synthesis of cyclotides through the intramolecular ligation of fully unprotected peptide O-esters.This strategy involves the mild Fmoc solid-phase peptide synthesis of the peptide O-ester backbone,the head-to-tail cyclization of the cyclotide backbone by native chemical ligation,and the oxidative refolding to yield the natural knot protein.The simplicity and high efficiency of the strategy can be employed in the synthesis of artificial cyclotides for pharmaceutical applications.