With the completion of crop genome sequencing, a large number of genes' functions affecting important agronomic traits of crops are waiting to be discovered. Due to the lack of genetic transformation methods, the research on gene function of most crops is progressing slowly. Virus-induced gene silencing (VIGS) technology does not rely on genetic transformation. Through virus vector inoculation, efficient silencing of targeted genes can be achieved in contemporary plants. VIGS technology is increasingly used in reverse genetics for analysis of gene functions and metabolic pathways in different crops due to its fast onset time, high silencing efficiency, low operating cost, high-throughput and wide application of plants. This article introduced the technical principles and development process of VIGS, systematically summarized the application of VIGS in different crop research, and then summarized and discussed the limitations of existing VIGS applications and several key factors affecting its silence efficiency, and finally the application in future plant biology research was prospected, which would provide reference for its further application and development.
As an important genetic engineering technique, genome editing has received widespread attention since its emergence. Just a few decades, genome editing has been developed rapidly. From the initial application of zinc finger endonuclease (ZFN) to the proficient utilization of transcription activitor-like effector nuclease(TALEN), followed by the discovery of clustered regularly interspaced short palindromic repeats (CRISPR), genome editing has continuously promoted the development and advancement of life science during the process of updating and improving itself. This review described the development genome editing along with the composition and mechanism of the CRISPR/Cas9 systems, and then, introduced its application in poultry functional genes and preparation on economically valuable gene model, and discussed the shortcomings of the current CRISPR/Cas9 technology in poultry, aiming to provide reference for the breeding related researches on poultry.
Rice is one of the major food crops in China, high yield and grain quality has always been the major goal of rice breeding. The improvement of breeding technology is conducive to enhance breeding efficiency. With the rapid development of plant biotechnology, rice breeding technologies have been also gradually improved. This review summarized several widely used breeding techniques in rice, including molecular marker assisted breeding, transgenic breeding, gene editing-based breeding and molecular design breeding, and discussed the development trend of these breeding techniques, which would provide reference for rice seed industry.
Ostrinia furnacalis (Asian corn borer) and weeds seriously affect maize growth, development and production in China. Transgenic stacking maizes with insect and herbicide resistance traits have become the main trend of transgenic maize breeding. cry1Ab, cry1F and cp4epsps were introduced into maize Hi-II mediated by Agrobacteria. After backcrossing with maize inbred line Zheng 58 and then self-pollination, one transgenic line named BFL4-1 was obtained. Through whole genome sequencing and flanking sequence analysis, there was one insertion in BFL4-1 and the insertion fragment was located in the intergenic region of chromosome 3. In BFL4-1 plants, cry1Ab, cry1F and cp4epsps were detected in different tissues on transcription and protein levels. Field experiments revealed that the BFL4-1 transgenic plants were highly resistant to Asian corn borer and more tolerant to glyphosate. There were no significant differences between BFL4-1 and the control (Zheng 58) on agronomic traits. Above results showed that BFL4-1 line could be served as a new maize transgenic line with stacked traits showing high resistance to insect and glyphosate.
To study the function of GhPKE1 in cotton, the structural characteristics of DNA sequence, physicochemical properties, hydrophobicity and secondary structure of GhPKE1, a heavy metal domain gene, were analyzed using bioinformatics method. And the virus-induced gene silencing (VIGS) carrier was constructed to infect cotton. The results showed that the length of GhPKE1 gene sequence was 1 048 bp, and its coden protein relative molecular weight was 27.54 kD, the isoelectric point was 9.3 and the instability coefficient was 35.56. After treated with Na2SO4 and CdCl2, the relative expression levels of GhPKE1 in silencing plant were significant lower than those in CK, and the resistances of silencing plant were significant decreased comparing with CK. The above results indicated that GhPKE1 gene played an important role in the response of cotton to stress, which laid a foundation for further research on the stress resistance mechanism of cotton.
Soybean interacts with rhizobia in the soil to fix the atmospheric nitrogen. The symbiotic nitrogen fixation process is complex and a series of genes are induced during nodule development. The carotenoid cleavage dioxygenases (CCDs) regulates anabolic metabolism of various plant hormones, pigments and aromatic compounds. In order to investigate the function of CCDs in biological nitrogen fixation, this study cloned GmCCD8 from soybean cultivar ZH15 to analyze its expression pattern and biological function. GmCCD8 was localized in cytoplasm. The expression pattern of GmCCD8 in soybean nodules were analyzed by qRT-PCR and histochemical GUS staining in transgenic soybean hairy roots and its expression increased during nodule development picked at 28th day. By analyzing composite transgenic soybean root nodules, GmCCD8 was found to affecte nodule fresh weight and nitrogenase activity. Ultrastructure of GmCCD8 RNAi nodules showed that the formation of vesicle, bacteroids and poly?β?hydroxybutyrate (PHB) in the root nodule was significantly reduced. The above results indicated that GmCCD8 was involved in soybean nodule development and nitrogen fixation, which provided functional genes for molecular breeding with efficient nitrogen fixation ability in soybean.
In order to explore the shrinkage phenomenon of wine grape at turning-color period in Hexi corridor, taking Vitisvinifera L. cv. Syrah as material, the effects of shading nets (different shading rates of 40%, 60% and 80%) on fruit shrinkage, fruit coloring and fruit surrounding environment during changed-color period were analyzed. The results showed that the shading net decreased the daily maximum temperature and the daily diurnal temperature of the microenvironment around the fruit, and increased the daily average humidity, and the solar radiation energy tended to be stable. After different shading treatments, the berry weight, cluster weight, longitudinal and horizontal diameter of fruit significantly increased, the fruit shrinkage significantly improved, and the yield increased more than one fold; the content of soluble solid, titratable acid, total phenol and tannin were decreased. The fruit quality index of 40% and 60% shading rate treatments did not evidently decrease, and the soluble sugar content between treatments had no significant difference. The L* and C* of each treatment were significantly lower than that of the control, and there was no significant difference in a* between the 40% and 60% shading treatments, while a* of 80% shading treatment was significantly lower than the control. The b* and CIRG of each treatment were higher than those of the control, the CIRG were more than 6, and the fruit was blue black. To sum up, shading treatment with shading rate of 40%~60% could effectively improve the fruit shrinkage during the turning-color period of ‘Syrah’. Those results provided guiding significance for improving the shrinkage phenomenon and improving the quality of wine grape.
In order to explore the response mechanism of Platycodongrandiflorum to drought stress and the effects of exogenous salicylic acid (SA) on drought resistance, the seedling of Platycodongrandiflorum was dealt with different concentrations of SA under different concentrations of PFG. The contents of chlorophyll (Chl), malondialdehyde (MDA), soluble sugar (SS), soluble protein (SP), proline (Pro) and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) were determined. And the relative expression levels of chlorophyllide a oxygenase (CAO) and chlorophyll synthase (CHLG), peroxidase (POD) genes related to Chlorophyll synthesis and pyrroline-5-carboxylate reductase gene (P5CR) related to proline biosynthesis were analyzed by the real-time fluorescence quantitative PCR. The results showed that exogenous salicylic acid in proper concentration could increase contents of Chl, SS, SP and Pro, improve activities of SOD, POD and CAT, reduce MDA content. And the relative expression levels of CAO, CHLG, POD and P5CR genes in leaves were consistent with the results of contents. In conclusion, exogenous salicylic acid could effectively improve drought resistance of Platycodongrandiflorus by increasing the contents of SS, SP, Pro and the activities of SOD, POD, CAT, which laid a foundation for dissecting the response mechanism of Platycodongrandiflorum to drought stress.
In order to reveal the adaptive mechanism of Pueraria lobate seedlings to low phosphorus stress, taking 3 different provenances of P.lobata from Australia, and Hunan and Jiangsu in China as experimental materials, and 3 different KH2PO4 treatments were set at a concentration of 0.5 (normal phosphorus), 0.05 (low phosphorus) and 0.005 (very low phosphorus) mmol·L-1. The growth and physiological response of P.lobata seedlings from 3 different provenances under different phosphorus treatments were measured. The results showed that the root indexes such as root length, root surface area and root diameter of three different provenances of P. lobata increased significantly under 0.05 mmol·L-1 treatment, leaf area, leaf perimeter and other leaf indexes also showed an upward trend (P<0.05), P. lobata had certain resistance to low phosphorus. Under 0.005 mmol·L-1 phosphorus treatment, the root morphological indexes of P. lobata from Hunan and Jiangsu were obviously suppressed, but the leaf morphological indexes of P. lobata from Hunan showed an increasing trend. The contents of proline, soluble sugar, malondialdehyde and activities of antioxidant enzymes (SOD, POD, CAT) in roots and leaves of P. lobata from 3 different provenances increased significantly under low and very low phosphorus treatments (P<0.05), but the content of soluble protein decreased. In summary, the P. lobata from Australian had strong tolerance of low phosphorus and had a high value for planting and promotion.
In order to study codon usage pattern of the genome of Wolfiporiacocos and its influencing factors, based on the nuclear and mitochondrial genome of W. cocos, the codon usage bias was studied using CodonW, Mega X and EMBOSS software. According to neutrality plot, parity rule 2 plot, ENC-GC3s plot and correspondence analysis, the influencing factors of codon bias of W. cocos were evaluated. The average GC content of nuclear genes of W. cocos was 57.28%, and G/C was preferred as the third nucleotide of codon. The analysis of influencing factors showed that the codon bias of nuclear genes of W. cocos were mainly affected by selection, while the mitochondrial genes were affected by mutation and selection effect. The RSCU values of synonymous codons in nuclear genes varied widely. Both of the high frequency codon and the optimal codons of the nuclear genes ended with G/C. The codon bias of nuclear gene was high, and the evolution process was strongly affected by environment and host selection in W. cocos. Compared with yeast, the codon usage pattern of Escherichiacoli was closer to W. cocos, so E. coli might be more suitable for heterologous expression of W. cocos. Above results could provide theoretical basis for the molecular evolution and transgenic research of heterologous genes.
The performance and reliability of tractor directly affect agricultural production efficiency. In view of the low accuracy of the loading control and measurement, single function and inconvenience of the current tractor loading test bench, this paper designed a dynamic loading bench for tractor. The bench not only completed multiple loading tests including PTO power, traction power and lifting capacity based on the national standard of tractor test, but also realized the dynamic loading test of load spectrum, which provided a test platform for the comprehensive detection of tractor performance parameters. In order to verify the dynamic characteristics of the loading platform, taking the tractor PTO loading test as an example, based on the NI-FPGA modular, the static step loading, sinusoidal follow loading and dynamic load spectrum loading tests of the loading bench were carried out. In the load spectrum loading test, the load spectrum prepared in the rotary tillage of TS404 was used as the input signal. The results showed that the maximum delay time was 0.8 s, the maximum overshoot was 9.81%, and the maximum error was 4.78%. The correlation coefficient of load spectrum was 0.997 0, and the goodness of fit was 18.94 N·m. All the results showed that the response time, control accuracy and system overshoot of the PTO loading bench could meet the actual loading needs, which provided the basis and reference for tractor performance and reliability test.
Taking Gulang Zhenfa photovoltaic field in Gansu Province as an example, this paper compared and analyzed the differences and variation characteristics of air temperature, wind speed and solar radiation inside and outside the photovoltaic power plant. The results showed that: ① desert photovoltaics could transform solar radiation, effectively regulate the thermal balance of desert surface, and reduce the power source (i.e. surface thermal) of sandstorm; ② sandstorm mainly occured in spring in Hexi corridor, so desert photovoltaic could effectively reduce the temperature of 10 m in spring; ③ desert photovoltaic was mainly through the conversion of solar radiation to reduce the temperature of the sand surface and its own sand barrier effect, and to improve plant growth conditions in three ways to prevent and control desertification and reduce dust storms.
Toxic fungi is easy to contaminate food and produce mycotoxins, especially in the growth and processing of cereal, among which aflatoxin is more harmful to human body, seriously endangering the health of consumers. Efficient food safety detection technology is important means to protect consumers from aflatoxin poisoning. This paper introduced the research progress of aflatoxin detection in food at home and abroad in recent years. The application and existing problems of high performance liquid chromatography(HPLC), liquid chromatography-mass spectrometry(LC-MS), enzyme-linked immunosorbent assay(ELISA), time-resolved fluorescence immunoassay(TRFIA), gold immune chromatography assay(GICT), surface enhanced Raman spectroscopy (SERS) and electrochemical sensor(ES) in the detection of aflatoxin in food were analyzed, so as to provide reference for related research.
In order to understand the relationship between different Macadamia germplasms and the amino acid composition of nuts, and screen germplasm resources of Macadamia variety suitable for functional amino acid beverage processing, 10 varieties of excellent macadamia germplasm were selected as materials, and the compositions and contents of amino acids of different Macadamia germplasms were analyzed. The quality characteristics of different Macadamia germplasms were evaluated by hierarchical cluster analysis (HCA), orthogonal partial further squares discrimination analysis (OPLS-DA)and other multivariate statistical analysis methods. The results showed that there were a complete range of amino acids in Macadamia nuts, and there were significant differences in contents of Glu, Arg and Met among different Macadamia germplasm. 10 Macadamia germplasms were classified into 2 groups by HCA, and the class Ⅱ including 6 Macadamia germplasms with better quality. OPLS-DA indicated the model was accurate and reliable, and characteristic amino acid fractions with significant differences between the 2 classes were found, which proved that the six Macadamia germplasms of Class Ⅱ had better overall amino acid quality with high contents of Glu and Arg. They could be used as germplasm resources for selecting and breeding Macadamia varieties suitable for functional amino acid beverage processing, which provided theoretical support for the effective breeding of Macadamia varieties and the high value utilization of Macadamia amino acid quality.
The degrading land caused by wind erosion and the subsequent desertification of farmland in Nnorthern China have been one of the severe eco-environmental problems, which mainly resulted by the long explosion of farmland during winter and spring seasons. The cultivation of winter rapeseed, winter wheat and the wheat stubble after harvest could effectively improve this issue, whose land coverage rates in winter were varied from 70% to 95%. The wind erosion modulus of winter rapeseed, winter wheat and wheat stubble were 22.3, 23.3 and 83.5 kg·hm-2·h-1,respectively, which were 4.10%, 4.28% and 15.36% of the control (spring seeded land, 543.6 kg·hm-2·h-1), respectively. This study summarized the research progress of winter cover crops and high-efficiency environmental protection planting technology of annual coverage in China. The application and dissemination of winter cover crops could guarantee constant organic surface coverage for the farmland in Northern China throughout the year, and had achieved great success in preventing winter erosion of farmland, which was of great significance to improve the agricultural quality and the ecological environment in north China.
In order to evaluate the risk of the spring frost damage to different wheat varieties in southern region of Shanxi under different accumulated temperature before winter and define the suitable sowing date and variety of adapting the change of current climate, two-factor splitting zone test including sowing date and variety was used to analyze the risk of wheat spring freezing injury. The test were arranged in two different climatic years from 2017 to 2018 (frost occurrence) and 2018 to 2019 (no frost), and 3 different ecological types of wheat varieties(Jimai 22, Zhoumai 18 and Xinong 529) were sowed at different date in Yanhu district of Yuncheng. The results showed that the accumulated temperature before winter (sowing date) had significant effect on wheat jointing and the risk of wheat spring freezing injury, the higher accumulated temperature before winter (the earlier sowing date) advanced the wheat jointing stage and increased the risk of freezing damage in spring. And variety with strong spring quality had higher risk to freeze damage. The average risk of frost damage in late March and early April were the highest when the accumulated temperature (≥0 ℃) before winter was 616.3 ℃, and were lowest when the accumulated temperature before winter was 390.1 ℃. In the year of frost occurrence, with the decrease of accumulated temperature before winter, the degree of freezing of wheat ear was reduced, the process of ear development was delayed, the relative membrane permeability was decreased, the content of MDA was decreased, and the activity of antioxidant enzymes were enhanced. The yield was consistent with the degree of freezing damage and the trend of evaluation of freezing damage. In no frost year, the yield showed a decreasing trend with the decrease of accumulated temperature before winter. However, the accumulated temperature before winter was moderately reduced, which had a little effect on the yield. Under the climate warming situation, the wheat yield could be more stable when the accumulated temperature (≥0 ℃) before winter was about 250~390 ℃, and the risk of freezing injury should be lower. Reducing the accumulated temperature before winter should be an effective way for wheat in environment of climate change.
In order to study the effects of Fenlong tillage on photosynthetic physiological characteristics and yield of sweet sorghum, 4 tillage methods, including conventional tillage (CK)?, Fenlong tillage to 30 (FL30) and 50 (FL50) cm depth, deep tilling to 40 cm depth (DT40), were set up in Helan Mountain farm, Yinchuan City, Ningxia Province, with ‘BJ0603’ as material. Agronomic traits, yield and photosynthetic physiological characteristics of sweet sorghum were measured and analyzed. The results showed that, compared with CK and DT40 treatments, the number of stem nodes, dry matter content, sugar content and grain yield of sweet sorghum significantly increased by Fenlong tillage (FL30 and FL50). The correlation analysis showed that the biological yield and grain yield were positively correlated with plant height, stem node number, dry matter content and sugar content. The photosynthetic physiological indexes of sweet sorghum cultivated with Fenlong tillage (FL30, FL50) were better than CK treatment during the whole growth stage, and better than DT40 treatment at flowering and maturity stages. Principal component analysis showed that the comprehensive values of FL50, FL30, DT40 and CK treatments were 0.20, 0.11, -0.03 and -0.14, respectively, which indicated Fenlong tillage was helpful to improve the photosynthetic physiological characteristics of sweet sorghum.
To study the synthesis method of a new water-soluble ammonium polyphosphate-rare earth slow-release fertilizer and its application effect on vegetables, the polymerization method was used to synthesize ammonium polyphosphate with low polymerization degree. By controlling the polymerization temperature and the ratio of raw materials, the polymerization degree, water solubility, nutrient content and pH of ammonium polyphosphate under different conditions were determined. On this basis, by controlling the dissolution method and dissolution temperature, the chelation of the rare earth metal lanthanum and cerium by the ammonium polyphosphate solution was explored. The fertilizer efficiencies of prepared ammonium polyphosphate and ammonium polyphosphate rare earth fertilizers were tested in field. The results showed that the average polymerization degree, contents of phosphorus pentoxide and nitrogen, and the water solubility of ammonium polyphosphate were 3.01, 48.07%, 26.38% and 1.92 g·mL?1, respectively, according to the procedure with 1∶1.5 of 85% phosphoric acid to urea, reaction time 20 min and reaction temperature 140 ℃. When ammonium polyphosphate aqueous solution was dissolved by ultrasonic at 50 ℃, the contents of chelated rare earth metal lanthanum and cerium reached to 541.0 and 757.4 mg·kg?1, respectively. Fertilizer efficiency experiments in field showed that ammonium polyphosphate and ammonium polyphosphate rare earth fertilizers had significant effects on promoting the growths of Chinese cabbage, eggplant and tomato, which provided new fertilizer varieties for realizing “reduction and efficiency increase” fertilizer goal.
The experiment with randomized block design was carried out to explore the influence of bio-organic fertilizer on flue-cured tobacco photosynthetic characteristic and rhizosphere soil microorganism, and research the effects of different application ratios of bio-organic fertilizer on photosynthetic parameters of flue-cured tobacco, quantities and diversities of microorganism in soil, and carbon utilization. Results showed that the application of bio-organic fertilizer made the photosynthetic characteristics of flue-cured tobacco, such as the SPAD values, net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration significantly increased, the treatment of 70% chemical fertilizer and 4 500 kg·hm-2 bio-organic fertilizer had the best effect. Appropriate application of bio-organic fertilizer could not only increase the number of bacteria, fungi and actinomycetes, but also improve the indexes of Shannon, Simpson and McIntosh, but the effect of excessive application was not significant. The results of principal component analysis showed that the soil microbial community had different metabolic characteristics of 6 type of carbon sources, such as carbohydrate, amino acids, polyphenolic amines, carboxylic acids, etc., which were most beneficial to the metabolism of carbohydrates and polymers. To sum up, the application of bio-organic fertilizer could significantly improve the photosynthetic and metabolic efficiency of flue-cured tobacco, enhance the carbon metabolism characteristics, and promote the formation of microbial quantities and community diversities. The treatment combining 70% chemical fertilizer and 4 500 kg·hm-2 of bio-organic fertilizer was optimal.
In order to explore the effects of stump on soil physical and chemical properties of protein mulberry forest and the best mulberry seedlings suitable for planting in the study area, the soils of protein mulberry forests with tree age of 2 years from 3 regions, including Tongliao in Inner Mongolia, Harbin in Heilongjiang and Xi’an in Shaanxi, were as research objects. Soil pH, mechanical composition, and the contents of available nutrients and organic matter were determined under 4 treatments including under the plant stump, under the plant-uneven stump, between the rows stump and between the rows-uneven stump. The correlation between soil particle composition and soil nutrients were analyzed. The results showed that the pH of soil was decreased and the content of silt was increased after stump. There were significant positive correlations between the content of very fine sand and the content of alkali-hydrolyzed nitrogen, organic matter and available potassium in the soil. The order of comprehensive evaluation of soil physical and chemical properties was Xi’an understory soil (0.463)>Tongliao understory soil (0.274)>Harbin understory soil (0.260). So the protein mulberry forest from Xi’an was suitable for planting in study area.
In order to investigate the distribution of the yellowfin tuna (Thunnusalbacares) fishing grounds in the tropical Central and Western Pacific Ocean, the isothermal distribution of subsurface temperatures in the yellowfin tuna fishing grounds was evaluated. The depths of 17 and 8 ℃ isotherm from the sea surface temperature (SST) (Δ8 ℃) were plotted on spatial overlay maps using data collected on a monthly basis from Argo buoys and monthly CPUE data (catch per unit effort) from Thunnusalbacares long-lines supplied by the Western and Central Pacific Fisheries Commission (WCPFC). In addition, the differences in depth between the 17 /Δ8 ℃ isolines and the lower boundary of the thermocline were computed to determine the relationship between Thunnusalbacares vertical distribution and thermocline depth. The overlay maps suggested that the distribution of Δ8 ℃ isothermal depth showed obviously seasonal variation, roughly in the zonal striped distribution on the annual mode. The spatial distribution of the Δ8 ℃ isothermal depth was deep in winter and shallow in summer. The catches per unite of effort (CPUE) were highest in areas where the 17 ℃ isothermal depth ranged from 180 to 279 m with the average depth 228 m. If the depth of 17 ℃ isothermal was greater than 300 m or shallower than 150 m, the CPUE tended to be lower. Similarly, the highest CPUEs were observed in areas where the Δ8 ℃ isothermal depth ranged from 120 to 239 m with the average depth 186 m. The horizontal distribution of high hook rates was concentrated in the area between 5°S and 10°N. The vertical distribution of Thunnusalbacares in the Central and Western Pacific Ocean was affected by the 17 and Δ8 ℃ isothermal depth, and the foraging depth of Thunnusalbacares was affected by the low boundary temperature and depth of the thermocline. At last the optimum ranges of subsurface factors were computed by the frequency analysis and the empirical cumulative distribution function. The optimum ranges for 17 and Δ8 ℃ isothermal depths were 160~300 m and 160~240 m, respectively. The optimum ranges of depth difference were 0~70 m for 17 ℃ isothermal depths and 30~109 m for Δ8 ℃ isothermal depths. The results were confirmed by using the Kolmogorov-Smirnov test. The distribution interval and vertical depth range for the central fishing ground of Thunnusalbacares were documented, and the results provided a reference for improving the efficiency of long-line fleet and resource management.
In order to evaluate the effects of planting densities and feeding frequencies on the growth and quality of crucian carp in the aquaponics system, an experimental aquaponics system (crucian carp+lettuce) based on substrate cultivation was set up in the greenhouse. The planting densities of lettuce were 28 (A1), 42 (A2) and 56 (A3) plants·m-2, the breeding densities of crucian carp were 8 (B1), 10 (B2) and 12(B3)kg·m-3 with the feeding frequency of 1 (C1), 2 (C2), 3(C3)meal·d-1. The growth and quality of crucian carp were determined for clarifying the optimal combination of planting density and feeding frequency under the aquaponics system. The results showed that the quality of water in each treatment was stable during the test period, and the growth indexes of crucian carp increased. The feeding density had significant effects on the weight gain rate, specific growth rate and feed coefficient of crucian carp, and A2B1C2 treatment was the best. The planting density and feeding frequency had significant effect on weight gain and protein efficiency, and A1B3C3 treatment was the highest with weight gain 303.56 g and protein efficiency 3.87, respectively. The water content of crucian carp was the highest when feeding frequency was 2 meal·d-1. There were no significant effects on fatness, crude protein, crude fat and other muscle components of crucian carp. In conclusion, the growth performance and quality of the crucian carp were optimal with planting density 42 plants·m-2, breeding density 8 kg·m-3 and feeding frequency 2 meal·d-1.
To develop a colloidal gold immunochromatographic test strip for on-site rapid detection of potato (Solanum tuberosum L.) virus X (PVX), virus Y (PVY) and virus S (PVS), three-fold (PVX-PVY-PVS) test strip was prepared by colloidal gold labeling and immunochromatography. Colloidal gold solution was prepared by trisodium citrate reduction method. Gold-labeled antibody, which was composed of gold atom and PVX, PVY and PVS antibody, was prepared by the combination of antibody and colloidal gold. The gold-labeled antibody was sprayed on the glass fiber by a three-dimensional film-spraying gold-spraying instrument, which was used as a gold-labeled pad. In the strip test,colloidal gold-labeled antibodies against PVX, PVY and PVS were sprayed on the glass fiber as the detection antibody, and rabbit anti-goat IgG at the control line, anti-PVX, anti-PVY and anti-PVS at the test line on the nitrocellulose membrane of the test strip were served as the capture antibody. The results showed that the three kinds of viruses (PVX, PVY and PVS) could be simultaneously detected within 5 min by the triple test strip .The detection was still feasible when the PVX samples was diluted by 104 (W/V),the PVY samples was diluted by 2×103 (W/V), the PVS samples was diluted by 103 (W/V), which was more sensitive to PVX detection. The triple test strip showed no cross effects to common 3 viruses (PLRV, PVA and PVM) samples. The results of triple test strip on potato leaves collected in the field were consist with DAS-ELISA. The triple test strip had the characteristics of simple operation and quick reaction, which should be suitable for field and port inspection especially.