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1.
In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components.  相似文献   

2.
The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electricheated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48h of cutting, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1% level (rNC89=-0.8962**, rYY85=-0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89=-0.8495*, rYY8*=-0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1% level (rNC89=0.9649**, rYY85=0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, -AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.  相似文献   

3.
To select the cementing and coating materials of slow/controlled-release fertilizer, the natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites through the methods of organic material intercalation, semiemulsification, and cut at high velocity techniques. Besides, two kinds of nano-subnanocomposites were tested in this study using several instruments, including the scanning electron microscope （SEM）, the X-ray diffraction （XRD）, the infrared ray spectrum （IR）, and the laser granularity. The main results were as follows： 1） The organic material was intercalated in the layers of kaoline clays, and the natural kaoline exfoliated into nanometer-sized layers. The organic agent and clays formed nanocomposites through hydrogen bond combination. 2） The SEM pictures of polystyrenestarch nano-subnanocomposites showed that many pores and rugas were present on the surface of film at sizes ranging from 10 to 20 nm. These nano-subnanocomposites were used as the cementing and coating materials of slow/controlledrelease fertilizer.  相似文献   

4.
针对目前我国烤烟专业化分级散叶收购的普遍实施。探讨了烤烟专分散收的优势，总结分析了专分散收过程中存在的问题，并针对这些问题提出了建议。以期为今后散叶收购工作的进一步推广提供实践经验。  相似文献   

5.
Pumpkin is a kind of crop which is often infected by viruses, in the past biology, serum and nucleic acid hybridization methods were mainly used on the study of pumpkin virus disease in China[1-2]. A lot of new PCR technologies have developed on base of P…  相似文献   

6.
An ester activation method was employed to couple enrofloxacin(ENFX) to the carrierproteins BSA and OVA. The conjugates ENFX-BSA and ENFX-OVA were identified with an UVspectrophotometer and amino acid automation analysis instrument, and resulted in conjugateswith 48 ENFX molecules per carrier molecule(BSA). Splenocytes from mice immunized withENFX-BSA were fused with SP2/0 myeloma cells and hybridomas secreting antibodies againstenrofloxacin were selected and cloned. Two stable monoclonal antibodies, 2C5, 5D5 of thesubclass IgG2a, were isolated. Using antibody 5D5, an indirect competitive inhibitionenzyme-linked immunosorbent assay (Ci-ELISA) was developed for the quantitative detectionof enrofloxacin and its metabolites. The IC50 of the standard curve was 21.67 ng mL^(-1) andthe limit of detection for enrofloxacin was 0.13 ng mL^(-1). This method was sensitive and hada linear range from 0.13 to I0 000ngmL^(-1) (r=-0.9782). Monoclonal antibody 5D5 exhibitedhigh relative affinity to enrofloxacin, and the cross-reactivities with ciprofloxacin,marbofloxacin, sarafloxacin and danorfloxacin were 110.8, 27.40, 71.05 and 37.41%,respectively. Three non-fluoroquinolones of cefadroxil, chloramphenicol, sulfadimethoxinewere tested and there was no cross-reaction between them.  相似文献   

7.
The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase- producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with twofold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta- lactamases （ESBLs）, The results revealed that most of 43 clinically isolated strains could produce beta-lactamase and 3 strains of shigella isolated from chicken samples produced ESBLs. All of 30 lactamase-producing strains isolated and only one of 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamaseproducing isolates decreased 10-40 and 10-20 times respectively, when it was conbined with sulbactam at ration of 1：2 and 1：4. All clinical isolates were susceptible to third-generation cephalosporins. The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased 2-4 times when they were conbined with sulbactam.  相似文献   

8.
To further utilize bioactive substance such as bovine colostrum sIgA and IgG,sIgA and IgG were isolated and purified simultaneously by salting out,ultrafiltration and gel chromatography,etc.The analysis of results were showed quantitatively by non-hydrogenized SDS-PAGE,and quanlities of sIgA and IgG were respectively detected by Western Blot.The results showed that the purity and yield of bovine colostrum sIgA were 85.3%and 42.8%,respectively,while the purity and yield of bovine colostrum IgG were respectively 97.2%and 64.4%.This preparative method provides theoretical and experimental foundation for sIgA industrial production.  相似文献   

9.
Laboratory studies were conducted to evaluate the risk of Phytophthora capsici developing resistance to two morphlines, dimethomorph and flumorph. Metalaxyl, the well-known high risk of resistance fungicides, was used as reference fungicide. Resistant mutants for the three fungicides were isolated by treating mycelium with ultraviolet radiation. Metalaxyl-resistant mutants were obtained with high frequency and exhibited high level of resistance with factors more than 100 folds, while mutation frequency for dimethomorph-resistance was relatively low and the resistance factors ranged from 3.0 to 13.9 folds. Most dimethomorph-resistant mutants decreased in hyphal growth rate and the spoulation ability, which have a large impact upon the epidemic development of dimethomorph-resistant populations. These results suggested that the risk of resistant pathogen population was much lower for dimethomorph than for metalaxyl. Both the frequency of developing resistance and level of resistance （resistance factors = 1.8-14.6） to dimethomorph were similar to those of its structure analogue flumorh. Moreover, the cross-resistance were found between them, which suggested the risks of developing resistance to dimethomorph and flumorph in the pathogen were very closely related. As P. capsici can potentially develop resistance to dimethomorph and flumorph, and oomycetes usually have the high risk to develop resistance to fungicides, appropriate management against resistance development should be taken.  相似文献   

10.
1　Introduction　　Sodium alginate and chitosan are the oceanic natural resources and high molecular com-pound which can promote the plant growth,and protect various plants from harmful organ-isms or prevent plant disease caused by harmful organisms( Makuuch,1 998and Hadwiger,etal. 1 983) .The two materials were used as coating materials,plant promoters,foliar sprayingin soil and so on( Mitchell,1 96 2 ;Brown,982 ;Cuero,1 991 ,Osuji,1 992 ) .Because the two ma-terials are degradable in soil …  相似文献   

11.
Safe strain identification and species recognition is an important issue for Trichoderma and Hypocrea, because members of the genus are economically important producers of industrial enzymes and antibiotics, have application as biocontrol agents against plant pathogens, whereas some have become known as opportunistic pathogens of immunocompromised mammals and humans. However, classical approaches based on the use of morphological and phenetic characters have been difficult to apply, due to…  相似文献   

12.
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13.
中国已成为继美国之后的全球第二大能源消费国,能源问题已成为制约一个国家经济发展的首要因素之一。目前,中国在解决能源问题方面,所采取的措施尚不能从根本上解决这一问题。提出能源农业的概念,系统阐述了能源农业的特点以及中国在发展能源农业方面所要采取的能源作物的筛选、培育、标准化栽培管理制度的建设、加工设备和加工工艺、能源转化设备转化效率和转化机制以及区域发展规划制定等一系列的基础及基础应用研究措施。  相似文献   

14.
ＴｈｅＥｆｅｃｔｏｆＨｉｇｈＴｅｍｐｅｒａｔｕｒｅａｎｄＣｌｅｎｂ－ｕｔｅｒｏｌｏｎＰｅｒｆｏｒｍａｎｃｅａｎｄＣａｒｃａｓｓＣｏｍｐｏｓｉｔｉｏｎｏｆＢｒｏｉｌｅｒｓＬｉＸｕｅ，ＬｉＹｕｚｈｉ，ＷａｎｇＱｉｎｇｈａｏ，ＭｅｎｇＸｉａｎｇｆｅｎｇ，Ｓ...  相似文献   

15.
Seed coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant.Sodium alginate and chitosan are high-molecular compound of two different kind,have the characteristic of promoting the crop growth,Using sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics.The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.5g.kg^-1.  相似文献   

16.
Effects of controlled-release fertilizers (CRFs) (C-AS, polyolefin coated ammonium sulfate, 50-day-type; Dd-LP, polyolefin coated urea with dicyandiamide, 40-day-type; C-ANP, polyolefin coated ammonium nitrate phosphate, 40-day-type; and C-DAP, polyolefin coated diammonium acid phosphate, 40-day-type), ammonium sulphate and no fertilizer control, and their application methods (spot, band, surface and mixed) on germination and seedling development of sweet corn (Zeamays L.var. saccharata Sturt.) and dent corn (Zea mays L.var. indentata Sturt.) were investigated in a greenhouse. Under co-situs application (band and spot) of CRFs, there were no obvious differences in the germination speed and rate for both dent corn and sweet corn relative to control. Mortality rates of sweet corn seedlings under co-situs application were high in experiment 1, but were very low in experiment 2, because the environmental conditions were different in the two experiments. That is, under lower temperature and weaker sunlight, young seedlings easily die due to high soil nutrient concentration and slow growth speed of corn. Shoot weight of both dent and sweet corn did not greatly decrease in experiment 1. In experiment 2, there were no significant differences in shoot and root weight of both corns between cositus and surface or mixed application methods. However, with spot and band application of ammonium sulfate, shoot and root weight were significantly reduced. Soil EC and pH were considerably affected by co-situs application, especially at the fertilizer application site. For both dent and sweet corn, EC in the 0-3 cm soil was significantly higher under co-situs application and surface application than that under mixed application, whereas in the 3-6 cm soil depth the situation was reversed. Compared with control, mixed application of CRFs decreased soil pH slightly (0-3 cm depth) or greatly (3-6 cm depth).  相似文献   

17.
An experiment was conducted to study the effects of different Chinese herbs on lactation in the rat. Seventy-two Sprague Dawley female rats at gestation day 18 were assigned to 9 groups randomly, with 8 rats each. Control rats were offered basal diets until the end of the weaning period. Rats in the other 8 groups were administered diets supplemented with 1% Medulla tetrapanacis (MT), Astragalus membranacens(AM), Vaccaria segetalis(VS), Leonurus heterophyllus sweet (LHS), Radix rehmanniae preparata (RRP), Squama manitis (SM), Schisandra chinensis (SC), Ligustrum lucidum (LL), respectively. After parturition, the litter size was culled to 8 pups per dam. Pup weight and milk yield were significantly higher in the VS, LHS, AM and SM groups than these in the control group during middle and late lactation (P<0.05 or P<0.01). The weight and feed intake were not different in the dams fed either diet.  相似文献   

18.
This research was to clone, express, and analyze the structure and function of major molecules of porcine interleukin family. Genes of porcine interleukin family were cloned by RT-PCR from stimulated porcine PBMC by LPS and PHA, and then expressed in E. coli, and the structure and function of these molecules were predicted by ExPASY. The results showed that genes of IL-4, IL-6, and IL-18 were successfully cloned and expressed. Furthermore, the expression products of recombinant IL-4 and IL-6 both have multiple biological activities. By analyzing these genes with the NCBI/GenBank data, the homologies of the nucleotide acid sequence are 99.25, 99.21, and 100%, respectively, and have great species differences when compared with other animal species. The results of the prediction showed that all these molecules contain several phosphorylation, glycosylation, protein kinase, and signal transduction bonding sites in secondary structure, and all are compact globularity protein in space configuration. These characteristics of structure are the basis for their multiple biological functions. The genes, structure and function of key molecular of porcine interleukin family were successfully cloned, expressed, and analyzed in this paper.  相似文献   

19.
In order to investigate the prompt conformations of swine major histocompatibility complex (MHC), a swine MHC-II protein complex (SLA-II) was reconstructed in vitro. DRA and DRB were cloned from a crossbred commercial pig (Changbai-Dalan). Subcloned extracellular parts of DRA and DRB were linked together by a linker containing rich glycine/serine (G4S)3, and the whole length of two genes, named DRA-linker-DRB, was amplified by splicing overlap extension PCR (SOE PCR). DRA-linker-DRB was inserted into pMAL-p2X prokaryotic system and expressed. The expressed fusion protein MBP-DRA-(G4S)3-DRB was identified by Western-blot, purified and cleaved to obtain the protein of interest DRA-(G4S)3-DRB. The secondary structure of this protein was determined in circular dichroism (CD) apparatus. The results indicated that the subsequent protein MBP-DRA-(G4S)3-DRB was soluble and its molecule weight was 83.4 ku in consistent with the Western-blot. Cleaved by Factor Xa, the protein of interest was separated with a molecular weight of 40.9 ku. The CD spectrum demonstrated that the protein displayed a favorable α-Helix structure, and the contents of α-Helix, β-sheet, turn, and random coil were 80 aa, 121 aa, 101 aa and 80 aa respectively. The identical ratios of α-Helix, β-sheet, turn, and random coil between MBP-DRA-(G4S)3-DRB and DRA-(G4S)3-DRB were 95%, 96.7%, 91.1% and 93.0%, respectively. The results also suggested that the reconstructed SLA-II complex presented an ideal conformation and can be used for studying its structure and function in vitro. __________ Translated from Journal of China Agricultural University, 2006, 11(3): 21–26 [译自: 中国农业大学学报]  相似文献   

20.
在分析水果和蔬菜品质评估和控制的常规方法的基础上 ,分析研究了水果蔬菜的无损品质检测的新技术和方法 ,主要的技术有碰撞试验法、音频和声波振动法、X射线法、核磁共振法、图像分析法及激光技术等 研究了采用这些方法进行水果和蔬菜多种品质指标的无损检测新方法 ,为水果蔬菜的快速无损检测提供了方法和依据  相似文献   

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