种子接种法测定紫花苜蓿不同品种对三叶草核盘菌的抗性

本试验采用种子接种法就10个紫花苜蓿(Medicago sativa L.)品种对三叶草核盘菌(Sclerotinia trifoliorum)的抗性进行了研究,根据接种后的种子萌发率、幼苗生长及幼苗干重三项指标的综合测定分析,供试品种中,游客和赛特受三叶草核盘菌影响最大,为高感品种;WL525和WL324受三叶草核盘菌影响最小,为高抗品种,其它6个品种介于两者之间,为中性材料。种子接种法便利、快捷,可以反映紫花苜蓿不同品种对三叶草核盘菌的抗性。

禾草-内生真菌人工接种技术研究进展

内生真菌侵染禾草既可提高宿主植物在群落中的竞争力,又可引起家畜中毒,因其特殊的双重特性而受到国内外学术界的广泛关注。由于禾草内生真菌具有宿主特异性使其资源的利用开发受到限制。随着分子生物学和基因组学的发展与应用,越来越多优良的内生真菌被发现,禾草组织培养再生体系也已逐步建立,对禾草内生真菌人工接种技术的传统方法有一定程度的改进。筛选具有优良特性的内生真菌菌株,通过人工接种的方法建立既对家畜无毒又能提高宿主品质及抗性的共生体是当前和今后研究的方向与热点。对现有的禾草内生真菌人工接种技术进行了综述,发现目前主要的接种方法有:无菌苗接种法、注射接种法、愈伤组织接种法、种子接种法和成株接种法。其中无菌苗接种法技术趋于成熟而应用广泛,但该方法与注射接种法均对植物有所伤害,增加了幼苗死亡率;愈伤组织接种法潜在成功率较高,但目前成熟的组织培养再生体系建立不完全而应用较少;种子切口接种法是新的接种方法的尝试,该方法操作简便,但目前并无成功接入的范例;种子浸菌接种法对植物组织造成的物理伤害小,幼苗存活率高,能够有效提高接种成功率。通过对现有人工接种技术的研究与探讨,以期借鉴开发其他微生物人工接种方法,同时探索新的接种成功率更高、相容性更好的接种手段,拓展内生真菌在禾草的共生范围,获得更多具有优良性状的共生体。

瓜类作物CGMMV-VIGS体系的优化研究

本研究旨在提高黄瓜绿斑驳花叶病毒(cucumber green mottle mosaic virus,CGMMV)介导的基因沉默(VIGS)在瓜类作物中应用效率。以黄瓜、甜瓜和西瓜优良种质为实验材料,采用不同的CGMMV病毒载体接种方式、并设置不同的培养温度和相对湿度,以测试基因沉默的有效性。结果表明,真空渗透和种子吸胀的接种方式能够在瓜类作物中产生最高的基因沉默率(FGS)。在22℃和25℃的培养环境下,黄瓜、甜瓜和西瓜PDS沉默有效性(EGSL)较高。黄瓜、甜瓜和西瓜生长1个月后,EGSL达到100%,显著高于30℃的培养环境下EGSL。生长3个月后,甜瓜和西瓜在22℃培养环境下EGSL分别为89.7%和95%;在25℃培养环境下EGSL分别为85.6%和86.1%,均显著性高于30℃下EGSL。在相对湿度为30%和50%环境下,黄瓜的EGSL分别为70%和72%,甜瓜的EGSL分别为76%和73%,显著高于相对湿度为80%的培养环境下EGSL。西瓜在相对湿度为30%的培养环境下的EGSL为69%,显著高于相对湿度为50%时的EGSL(38%)和相对湿度在80%时的EGSL(33%)。综上所述,通过优化了瓜类作物的CGMMV-VIGS的技术体系中接种方式和培养环境参数,提高了基因沉默率和有效性,并且能够快速获得整个植株基因沉默的种质资源,为作物优质和抗逆基因功能的研究提供有效途径。

不同品种紫花苜蓿种子对菌核病菌的耐受性研究

为了尽可能的降低和避免因苜蓿菌核病给生产者造成的巨大经济损失,本试验采用种子接种法,以赛迪7、WL525、WL903、游客、三得利、超音速、维多利亚、猎人河种子8个品种紫花苜蓿种子为材料,研究了不同品种紫花苜蓿种子对菌核病菌的耐受性。结果显示:在接种2h、4h、6h后,维多利亚相对腐烂率分别在第8d、第7d、第7d达到0.900,表现感病;赛迪7的相对腐烂率分别在第10d,第10d,第9d达到0.900,表现抗病;从第4d到第9d,接种4h时,品种间差异性最显著,最适于抗病品种的筛选。

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.

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.

Controlling the lateral and vertical dimensions of Bi2Se3 nanoplates via seeded growth

Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi2Se3 nanoplates slightly increased from N7.5 nm （seeds） to -9.5 nm while the edge length grew up from ~160 nm （seeds） to N12 ~tm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to -35 nm and -6 b^m after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi2Se3 thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi2Se3 nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.