开沟式植苗机构钵体低损接苗机理与试验研究

针对导苗管式植苗机构存在因机构高度较大发生钵苗破损严重的问题,建立植苗机构在底部平面碰撞和楔形侧面护钵两种接苗方式下蔬菜钵苗钵体与植苗机构碰撞接触的力学模型,计算得出两种接苗方式下钵体所受到的最大碰撞力分别为29.27 N和7.66 N。应用离散元软件EDEM进行两种接苗方式下钵体与植苗机构碰撞接触的仿真分析,两种接苗方式的仿真分析与理论计算所得到的钵体最大碰撞力基本一致,验证钵体与机构碰撞接触力学模型的可靠性和分析结果的正确性。开展蔬菜钵苗在两种接苗方式下的跌落碰撞试验,楔形侧面护钵接苗方式的钵体破损率为0.77%,明显低于底部平面碰撞接苗方式的1.69%。研究表明:采用楔形侧面护钵接苗方式,蔬菜钵苗钵体所受到的碰撞力小,有利于降低钵体损伤率、提高钵苗植苗质量,可为开沟式植苗机构的设计提供理论和试验依据。

果树休眠芽接苗温室摧苗定植方法

果树休眠芽接苗温室催苗定植是我们近年来试验的一种快速培育果树苗的新方法.其法是在春季露地苗圃播种、8月份芽接、接后不剪砧,入冬前起苗假植越冬.第二年早春在室内用电温床催根,20余天后,再移栽入温室营养袋内,生长两个月于晚霜过后在果园定植.我们采用的果苗、有苹果500株,桃树250株.定植时高度已达0.8—1.0m、主茎粗度已达1.2—1.6cm.我们定植了苹果200株,桃树30株作栽植观察,达到了全栽全活.到秋季,新梢长度达60cm以上,已达到整形的要求,桃树已形成了饱满的花芽,来年挂果有保证.而常用的果树快速育苗,即所谓的“三当苗”是常年在保护地当年播种当年芽接当年出圃;因要夏季剪砧、营养物质损耗很大,育成的苗子很难达到定植的规格要求,主要表现在枝干幼嫩不充实,高度粗度不够格,根系很弱,定植后当年很难萌发出健壮的新梢,也就达不到整形的要求,这样育苗的时间虽然缩短了,而果树进入结果期的时间却延长了.生产中是得不偿失的,因此近年来。

甜瓜靠接苗接穗断根要彻底

山东省夏津县近几年大力发展设施蔬菜生产,早春大棚甜瓜种植规模不断扩大。为了进一步增加种植效益,该县蔬菜技术人员指导菜农采用多膜覆盖和嫁接育苗技术,引入早熟、抗病、丰产的甜瓜新品种,提早育苗,提早定植,提早上市,促进了农民大幅度增收。不久前,夏津县苏留庄镇小石堂村一位甜瓜种植户来电向笔者咨询,说他种的早春大棚甜瓜苗大部分都萎蔫死亡了,不知咋回事。

不同品种美国山核桃芽苗砧嫁接成活率及生长过程分析

以‘斯图尔特’、‘卡多’、‘契科特’和‘德西拉布’4个美国山核桃品种休眠枝为接穗,进行芽苗砧嫁接试验,比较不同品种美国山核桃芽砧嫁接苗接芽萌发动态、成活率及新梢生长量的差异。结果表明:嫁接后第15,20,25天,各品种接穗芽砧嫁接苗萌发生长差异显著;嫁接时间、接穗品种对美国山核桃芽苗砧接成活率存在显著影响;不同品种美国山核桃芽苗砧接嫁接苗新梢生长差异显著。

浅谈针叶树种嫁接育苗技术

本文从砧木与接穗的选择、接穗的采集与贮藏、嫁接以及嫁接后的接苗管理4个方面阐述了针叶树种嫁接育苗技术,为嫁接实践工作者提供参考。

桑树袋接子苗建园技术

用袋接子苗建桑园,不仅可以解决目前各地桑苗不足的问题,还可达到桑园当年丰产的目的,可谓一举两得。——培育子苗。先在背风向阳处准备好苗床。床宽1～1.5米,深20～25厘米。

油茶芽苗砧接圃地培育技术研究

从加速油茶良种繁育速度和提高圃地利用率出发，探讨了油茶芽苗砧接一年生苗上山造林圃地培育技术。通过采用ABT生根粉处理，圃地管理和容器移栽等方法，解决了一年生嫁接苗根系不发达以及造林成活率低的问题，达到了试验设计的目的。

橡胶树大筒苗培育方法Ⅱ——砧木材料的筛选

为了培育出可缩短非生产期、减少抚管用工的橡胶树大筒苗,在小筒苗育苗技术的基础上探索大筒苗胚苗材料的类型和规格问题。以籽接苗和芽接桩为胚苗,按不同的砧木直径设12个处理,采用中空锥形筒为育苗容器,分析了各处理大筒苗的株高、茎粗、叶篷数等生长参数和出圃率、定植成活率等出圃参数,并用隶属函数法对不同处理的育苗效果进行大筒苗砧木材料的综合评价和筛选。结果表明,芽接桩砧木直径(1.0~1.1 cm)较小的T 2和T 3大筒苗生长势较弱,出圃率较低,约为65%;1.2~1.7 cm的T 4~T 9大筒苗株高均在2 m以上,叶蓬数近7蓬叶,出圃率80%以上;1.8~2.0 cm的T 10~T 12大筒苗茎粗均在1.8 cm以上,但出圃率低于75%。各处理的大田定植成活率均在92%以上。若需要培育至6~8蓬叶、株高2 m以上、出圃率80%以上的大筒苗,芽接桩的砧木直径需在1.2 cm以上,适宜范围为1.5~1.7 cm,不宜超过1.8 cm。综合考虑各处理的育苗效果,以砧木直径1.6 cm左右的芽接桩T 8作为胚苗的大筒苗生长良好,株高2.2 m以上、茎粗1.8 cm以上,叶蓬数近8蓬叶,出圃率高达92%,定植成活率达95%,是培育橡胶树大筒苗的适宜砧木直径。若同时考虑省时省力又节约育苗成本,籽接苗T 1也适合作橡胶树大筒苗的砧木材料。

Vaccination in three different ways against vibriosis of Seriola dumerili caused by Vibrio hollisae

Bacterin was prepared by formalin-inactivating the virulent strain of Vibrio hollisae isolated from diseased Seriola dumerili （amberjack） suffering from vibriosis. Healthy S. dumeriIi were vaccinated by respective procedures of intramuscular injection, immersion, and orally administration. Results of the three different vaccinations were compared. Blood was drawn from the vaccinated fish every 7 days, and the antibody titers and lysozyme activities of the sera were determined. The antibody titer of injected fish was 1：40 at 7 d, and reached its peak of 1：320 at 28 d, while the fish vaccinated by immersion and orally administration exhibited weak antibody responses, the antibody titres of 〈1：10, 1：20, 1：160 were observed at 7 d, 14 d, 35 d respectively. Compared with the control, the vaccinated fish exhibited significantly higher lysozyme activities （P〈0.05）. Upon challenge with virulent strain, the relative percent survival （RPS） of injected, immersed and oral administrated fish were 75%, 45%, and 40% respectively, and the injected fish showed significantly higher RPS than immersed and oral administrated fish. The results suggested that vaccination of S. dumerili by the injection would be the best strategy to prevent the vibriosis in S. dumerili farm.

Study on Passive Immunity:time of Vaccination in Kids Born to Goats Vaccinated Against Peste des petits ruminants

In this study,the decay of maternal peste des petits ruminants virus(PPRV) antibodies in kids born to goats vaccinated with Asian lineage IV PPR vaccine and the efficacy of passive immunity against PPRV was assessed to determine the appropriate period for vaccination in kids.Serum samples collected from kids born to vaccinated,unvaccinated and infected goats at different time intervals were tested by PPR competitive ELISA and serum neutralization test(SNT).Maternal antibodies in kids were detectable up to 6 months with a decline trend from the third month onwards and receded below the protective level by the fourth month.The kid with an SN titre of 1:8 at the time of immunization showed significant PPRV specific antibody response(percentage inhibition of 76;SN titers >1:16),when tested on 21 day post-vaccination and was completely protected from infection upon virulent PPRV challenge.Similarly,the kid with 1:8 SN titers was completely protected from PPR infection on active challenge.Therefore,PPR vaccination is recommended in kids,aged 4 months and born to immunized or exposed goats.This could be a suitable period to avoid window of susceptibility in kids to PPRV and the effort to eliminate PPR infection from susceptible populations.

An effective vaccine against colon cancer in mice:Use of recombinant adenovirus interleukin-12 transduced dendritic cells

AIM： To investigate the effect of a vaccine with recombinant adenovirus interleukin-12 （AdVIL-12） transduced dendritic cells （DCs） against colon cancer in mice. METHODS： DCs and AdVIL-12 were incubated together at different time intervals and at different doses. Supernatant was collected and tested for IL-12 by enzyme-linked immunosorbent assay （ELISA）. In order to determine whether tumor cell lysate-pulsed （TP） AdVIL-12/DCs enhance therapeutic potential in the established tumor model, CT26 colon tumor cells were implanted subcutaneously （s.c.） in the midflank of naive BALB/c mice. Tumor-bearing mice were injected with a vaccination of CT26 TP AdVIL-12/DCs on d 3 and 10. As a protective colon tumor model, naive BALB/c mice were immunized s.c. in their abdomens with CT26 TP AdVIL-12/DCs twice at seven day intervals. After the immunization on d 7, the mice were challenged with a lethal dose of CT26 tumor cells and survival times were evaluated. Subsequently, cytotoxic T lymphocyte （CTL） activity and interferon gamma （IFNy） secretion was evaluated in the immunized mice, and assayed CTL ex vivo. RESULTS： Murine DCs were retrovirally transduced with AdVIL-12 efficiency, and the AdVIL-12 transduced DCs secreted a high level of IL-12 （AdVIL-12/DCs, 615.27 ± 42.3 pg/mL vs DCs, 46.32 ± 7.29 pg/mL, P 〈 0.05）. Vaccination with CT26 TP AdVIL-12/DCs could enhance anti-tumor immunity against CT26 colon tumor in murine therapeutic models （tumor volume on d 19：CT26 TP AdVIL-12/DCs 107 ± 42 mm^3 vs CT26 TP DCs 383± 65 mm^3, P 〈 0.05） and protective models. Moreover, the CT26 TP AdVIL-12/DC vaccination enhances tumor-specific CTL activity, producing high levels of IFN7 in immunized mice. Ex vivo primed T cells with AdVIL-12/DCs were able to induce more effective CTL activity than in primed T cells with CT26 TP/DCs （E：T = 100：1, 69.49% ± 6.11% specific lysis vs 37.44% ＋ 4.32% specific lysis, P 〈 0.05）.CONCLUSION： Vaccination with recombinant AdVIL-12 transduced DC pulsed tumor cell lysate enhance antitumor immunity specific to colon cancer in mice.

Immune response to an indigenously developed r-Hepatitis B vaccine in mixed population: Study of an accelerated vaccination schedule

AIM: To establish the safety and efficacy of an indigenously developed r-hepatitis B vaccine using an accelerated schedule and to highlight the social awareness and commitment in preventing the spreading of hepatitis B virus infection. METHODS: The study was a multicentric, double blind, randomized (3:1) study using three doses of vaccine immunization schedule (20μg for those above 10 years old and 10 μg for those below 10 years old) on d 0, 30 and 60. One hundred and sixty-six subjects were enrolled (87 males and 76 females aged 5-35 years). The main outcome measure was assessment of immunogenicity and safety. RESULTS: A 100% seroconversion response was observed on the 30th d after the 1st injection in both the experimental groups. The sero-protection data reported a 41.2-65.6% response on the 30th d after the 1st injection and reached 100% on the 60th d. Descriptive statistical analysis showed a geometric mean titer value of 13.77 mIU/mL in the test (BEVAC) group and 10.95 mlU/mL in the commercial control (ENGERIX-B) group on the 30th d after the 1st injection. The response on the 60th d showed a geometric mean titre value (GMT) of 519.84 mlU/mL in the BEVAC group and 475.46 mlU/mL in the ENGERIX-B group. On the 90th d, the antibody titer response was observed to be 2627.58 mlU/mL in the BEVAC group and 2272.72 mlU/mL in the ENGERIX-B group. Two subjects in each group experienced pains at injection site after the first vaccination. A total of six subjects in both groups experienced a solicited adverse reaction, which included pains, swelling and redness at the injection site, three subjects in the group-B had a pain at the injection site after the third dose. No other serious adverse events occurred and no dose-related local or general symptoms were observed during the study. CONCLUSION: The vaccine is safe, efficacious and immunogenic in comparison with the well documented ENGERIX-B.

Therapeutic effect of autologous dendritic cell vaccine on patients with chronic hepatitis B: A clinical study

AIM: To investigate the therapeutic effect of autologous HBsAg-loaded dendritic cells (DCs) on patients with chronic hepatitis B. METHODS: Monocytes were isolated from fresh peripheral blood of 19 chronic HBV-infected patients by Ficoil-Hypaque density gradient centrifugation and cultured by plastic-adherence methods. DCs were induced and proliferated in the culture medium with recombinant human granulocyte-macrophage-colony- stimulating factor (rhGM-CSF) and human interleukin-4 (rhIL-4). DCs pulsed with HBsAg for twelve hours were injected into patients subcutaneously twice at intervals of two weeks. Two patients received 100 mg oral lamivudine daily for 12 mo at the same time. HBV-DNA and viral markers in sera of patients were tested every two months. RESULTS: By the end of 2003, 11 of 19 (57.9%) patients had a clinical response to DC-treatment. HBeAg of 10 (52.6%) patients became negative, and the copies of HBV-DNA decreased 101.77±2.39 averagely (t = 3.13, P<0.01). Two cases co-treated with DCs and lamivudine had a complete clinical response. There were no significant differences in the efficient rate between the cases with ALT level lower than 2xULN and those with ALT level higher than 2xULN before treatment (X2 = 0.0026). CONCLUSION: Autologous DC-vaccine induced in vitro can effectively suppress HBV replication, reduce the virus load in sera, eliminate HBeAg and promote HBeAg/anti-HBe transformation. Not only the patients with high serum ALT levels but also those with normal ALT levels can respond to DC vaccine treatment, and the treatment combining DCs with lamivudine can eliminate viruses more effectively.

A VIBRIO ANGUILLARUM STRAIN ASSOCIATED WITH SKIN ULCER ON CULTURED FLOUNDER, PARALICHTHYS OLIVACEUS

The characteristics of a bacterium strain M3, isolated from cultured flounder Paralichthys olivaceus with remarkable external sign of skin ulcer during an epizootic outbreak, indicated that the bacterium belonged to the species Vibrio anguillarum . Challenge by I.M. (intramuscular injection), bath, and oral administration with M3 showed that it was highly pathogenic for Paralichthys olivacues . The LD 50 dose was 5.144×10 3 CFU/ per fish infection by I.M. injection. Recovered inoculated bacteria from the surviving fish revealed that the asymptomatic carriers could be a latent contagious source. Study of the effect of bacterial culture CFS (cell free supernatant) showed that the exotoxins produced by M3 play an important role in its pathogenicity for flounder. The resistance of M3 to 36 out of 41 antibiotics indicated that the bacterial disease outbreak was mainly attributable to the frequent and excessive use of antimicrobial agents; and that vaccination would be an effective precaution against bacterial disease.

Oral vaccination of mice against rodent malaria with recombinant Lactococcus lactis expressing MSP-1_(19)

AIM： To construct the recombinant Lactococcus/actis as oral delivery vaccination against malaria. METHODS： The C-terminal 19-ku fragments of MSP1 （MSP-119） of Plasmodium yoelii265-BY was expressed in L. lactis and the recombinant L. lact/s was administered orally to BALB/c and C57BL/6 mice. After seven interval vaccinations within 4 wk, the mice were challenged with P. yoelii 265-BY parasites of erythroo/tic stage. The protective efficacy of recombinant L. lactiswas evaluated. RESULTS： The peak parasitemias in average for the experiment groups of BALB/c and C57BL/6 mice were 0.8± 0.4% and 20.8±26.5%, respectively, and those of their control groups were 12.0±0.8% and 60.8±9.6%, respectively. None of the BALB/c mice in both experimental group and control group died during the experiment. However, all the C57BL/6 mice in the control group died within 23 d and all the vaccinated mice survived well. CONCLUSION： The results imply the potential of recombinant L. lactis as oral delivery vaccination against malaria.

Improvement of the efficacy of influenza vaccination (H5N1) in chicken by using extract of Cochinchina momordica seed (ECMS)

Seeds of a Chinese traditional medicine plant, Cochinchina momordica were used in the present study for the improvement of influenza vaccine （HSN 1） in chicken. Crude extraction from Cochinchina momordica seed （ECMS） was obtained by ethanol extraction method. In experiment No. 1, two weeks old chickens were immunized with influenza vaccine （HSN1） alone or combined with ECMS （5, 10, 20, 40 and 80 μg/dose）. Serum IgG antibody levels （by ELISA） as well as effects on dally weight gain were measured on 0, 7, 14 and 28th day after immunization. Results revealed that all ECMS groups numerically increased the antibody levels while 10 and 20 μg/dose groups significantly （P〈0.05） enhanced total IgG antibody on day 28, when compared with control. Average daily weight gain was also significantly higher in 20 μg/dose ECMS group. Adjuvant effect was also confirmed in experiment No. 2 when chickens were immunized with 20 μg/dose ECMS and antibody titer was measured through hemagglutination inhibition （HI）. It is concluded that ECMS has potential to improve the immune responses and deserve further study as an adjuvant.