高效液相色谱法测定齿毛芝中的碱基

采用250SS4.6-ODSZ-8/5色谱柱,体积分数20%的甲醇为流动相,紫外260nm检测,尿嘧啶,尿苷,腺嘌呤腺苷的保留时间分别为2.23min,2.97min,4.13min和6.74min,检测齿毛芝中碱基的摩尔比依次为1`.24:0.41:2.29:2.05.     

高压电压互感器的可靠性数据统计分析

本文根据高压电压互感器现场运行的调查材料,用概率统计的方法求出其寿命函数,并估计其平均故障率,为高压电压互感器的可靠性管理提供依据和参考。     

加热光纤法同步测定土壤水热参数误差分析

土壤水热参数是研究土壤水热传输的基本物理参数。当前热脉冲探针法（HPP）可同步测定土壤水热参数,但该方法仅限于在点尺度下测定。与其具有相同理论基础的加热光纤法（SPHP-DTS）,可将测定尺度增大至田间千米尺度,但其测定精度尚未得到有效验证。为了探知SPHP-DTS法的误差,本研究进行了SPHP-DTS法与HPP法测定土壤水热参数的对比试验。结果表明,以HPP为标准,加热光纤法测定热导率的精度RMSE为0.13 W?m-1?℃-1。SPHP-DTS法测定的热导率显著高于HPP法,主要原因在于加热光纤时产生的温度效应。通过热导率法测定土壤含水率时,在热导率测定误差的影响下,SPHP-DTS法的测定精度明显低于HPP法。SPHP-DTS法测定土壤水热参数的其他误差来源包括光纤与土壤之间多个界面的接触热阻、光纤的温度敏感性、噪音干扰以及温度梯度驱动下的水分迁移。本研究可为SPHP-DTS法提升土壤水热参数测定精度提供理论参考。     

Comparison of the effects of salicylic acid and ethephon with virus-induced hypersensitivity and acquired resistance in tobacco

The induction of a hypersensitive reaction in Samsun NN tobacco by tobacco mosaic virus (TMV) at 20°C leads to the development of both localized and systemic acquired resistance, and is associated with the appearance of pathogenesis-related proteins (PR's) and large increases in peroxidase activity and ethylene production. Salicylic acid (SA) induced a similar resistance in treated plant parts and occasionally also in untreated upper leaves of plants of which three lower leaves had been injected. SA also induced the same four PR's, but these were confined to the treated leaves. Thus, the connection between the presence of PR's and the reduction of TMV multiplication and spread may not be direct.In contrast to TMV, SA did not stimulate ethylene production and hardly increased peroxidase activity. Induction of acquired resistance and PR's by SA developed equally well at 20°C and at 32°C. However, pricking leaves with needles moistened with the ethylene-releasing compound ethephon mimicked TMV infection in inducing acquired resistance and PR's in both treated and untreated leaves at 20°C, but not at 32°C. Ethephon increased peroxidase activity at both temperatures, but only at 20°C dit it induce changes in both the anodic and the cathodic isoenzymes that were similar to those induced as a result of TMV infection. SA induced PR's and reduced TMV multiplication in Samsun tobacco, and inhibited virus spread in Samsun NN at 32°C.These observation indicate that neither the induction of PR's, nor the development of acquired resistance is temperature-sensitive. On the other hand, the effects of ethephon are temperature-sensitive in the same way as the hypersensitive response to TMV. It can thus be hypothesized that ethylene, produced naturally during the hypersensitive reaction of tobacco to TMV, leads to the temperature-sensitive synthesis or release of a presumably benzoic acid-type compound that functions as the natural inducer of PR's and acquired resistance. Although vanillic acid has been shown to accumulate in hypersensitively reacting tobacco leaves, it produced none of the effects of SA, and thus cannot be the natural inducer.Samenvatting Inductie van een overgevoeligheidsreactie in Samsun NN-tabak door tabaksmozaïekvirus (TMV) bij 20°C leidt tot de ontwikkeling van een verworven resistentie die zowel lokaal als systemisch werkzaam is, en gaat samen met het verschijnen van pathogenesis-related proteins (PR's) en sterke toename in de activitieit van peroxidase en de produktie van ethyleen. Salicylzuur (SA) induceerde een vergelijkbare resistentie in behandelde plantedelen en af en toe ook in niet behandelde bovenbladeren van planten waarvan drie onderbladeren waren ingespoten. SA induceerde ook dezelfde vier PR's, maar deze waren beperkt tot de behandelde bladeren. Er bestaat dus geen directe samenhang tussen de aanwezigheid van PR's en de remming van de vermeerdering en uitbreiding van TMV in de plant.In tegenstelling tot TMV stimuleerde SA de ethyleenproduktie niet en verhoogde het de peroxidaseactiviteit nauwelijks. Inductie van verworven resistentie en PR's door SA trad even goed op bij 32°C als bij 20°C. Net als infectie met TMV leidde aanprikken van bladeren met naalden die gedoopt waren in een oplossing van ethefon — waaruit in het blad ethyleen vrijkomt — echter tot inductie van verworven resistentie en PR's in zowel behandelde als onbehandelde bladeren bij 20°C, maar niet bij 32°C. Ethefon verhoogde de peroxidaseactiviteit bij beide temperaturen, maar alleen bij 20°C induceerde het veranderingen in zowel de anodische als de kathodische isoënzymen die vergelijkbaar waren met die welke geïnduceerd werden als gevolg van infectie met TMV. SA induceerde PR's en verminderde de vermenigvuldiging van TMV in Samsun tabak, en remde de uitbreiding van het virus in Samsun NN bij 32°C.Deze waarnemingen tonen dat noch de inductie van PR's, noch de ontwikkeling van verworven resistentie een temperatuurgevoelig proces is. Daarentegen zijn de effecten van ethefon op dezelfde wijze temperatuurgevoelig als de overgevoeligheidsreactie op TMV. Men kan daarom veronderstellen dat ethyleen, dat op natuurlijke wijze geproduceerd wordt tijdens de overgevoeligheidsreactie van tabak op TMV, aanleiding geeft tot een temperatuurgevoelig proces, namelijk de synthese of het vrijkomen van een verbinding, vermoedelijk een benzoëzuurderivaat, dat fungeert als de natuurlijke inductor van PR's en verworven resistentie. Hoewel is aangetoond dat vanillinezuur zich ophoopt in overgevoelig reagerende tabaksbladeren, veroorzaakte deze verbinding geen enkel van de effecten van SA. Vanillinezuur kan dus niet de natuurlijke inductor zijn.     

新疆石河子地区沙漠增温效应对绿洲农业影响的研究

由于沙漠 ,绿洲 ,空气的比热等热性能不同 ,形成沙漠夏季温度明显高于绿洲 ,进而对绿洲地区增温 ,称沙漠增温效应。石河子地区 1 0 0 km范围内沙漠对绿洲的增温平均 1 .76℃ ( 1～ 2℃ ) ;根据绿洲距沙漠的远近与气温间存在的线性关系 ,回归方程为 :y=2 7.5 2 97- 0 .0 335 x。 r=- 0 .881 3*。沙漠增温效应对绿洲农业有多方面作用 ,形成夏季富照高温、秋季大日较差以及促成棉花在夏季的“冷害”等 ,深刻地影响绿洲特色农业、栽培技术及人们生活     

Leaf, floret and seed infection of wheat by Pyrenophora semeniperda

Infection processes of Pyrenophora semeniperda on seedling and adult wheat leaves and wheat ears were investigated. Almost 100% germination of conidia occurred on seedling leaves, compared with 20–30% on adult leaves. Appressoria formed over the anticlinal epidermal cell walls and haloes always accompanied infection. Sometimes papillae formed within the leaves as a resistance mechanism. Infection hyphae ramified through the intercellular spaces of the mesophyll resulting in cellular disruption. The infection processes on floral tissues were similar to those observed on leaves; however, no infection occurred on anther, stigmatic or stylar tissues. Infection of ovarian tissue occurred both with and without appressoria formation. Hyphae grew mainly in the epidermal layers and appeared unable to breach the integumental layer as no growth was observed in endosperm or embryo tissues. The optimum dew period temperature for conidial germination was 23·6°C, compared with 19·9°C for lesion development, 20·4°C for the production of infection structures on seedling leaves and 23·7°C for floret infection. Leaf disease development occurred in a logistic manner in response to dew period, with maximum infection observed after 21 h compared with > 48 h in seeds. An initial dark phase during the dew period was necessary for infection and temperature after the dew period had an effect, with significantly more numerous and larger lesions being formed at 15°C compared with 30°C. Seedling leaves were found to be more susceptible than older leaves, under both field and controlled environment conditions. Infection of wheat seeds following inoculation of ears, or after harvest burial of inoculated disease-free seeds, was demonstrated. In the latter, 3-week-old seedlings were slightly stunted, whereas older plants were unaffected. The apparent unimportance of this plant pathogen as a cause of leaf disease in relation to its poor adaptation to dew periods and dew period temperature is discussed, along with the importance of its seed borne characteristics.     

山羊高床舍饲配套饲养技术探讨

山羊高床舍饲技术通过修建标准化山羊圈舍，实现山羊饲养过程中对山羊个体的有效控制和辅助，降低饲养劳动量和劳动强度；通过带动种草养羊、养羊与沼气结合，在实现山羊饲养的同时，促进了退耕还草、封山育林等生态建设项目的实施。     

根际生命共同体：协调资源、环境和粮食安全的学术思路与交叉创新

植物营养学研究近年来在植物养分高效分子机理、植物-微生物互作、根际互作与微生态调控、农田养分管理等研究领域取得了一系列原创性进展。然而,当前如何协调粮食安全、资源高效和环境可持续性仍面临巨大挑战。针对这一重大问题,本文提出"根际生命共同体(Rhizobiont)"学术思路,围绕"根际互作与养分高效"这一重大科学命题,构建"植物-根系-根际-菌丝际-土体及其微生物"根际生命共同体理论体系,突破植物-微生物、微生物-微生物关键界面互作机制,阐明根际生命共同体结构、功能及其在养分活化、吸收与利用中的作用机制,建立共同体多界面互作增效的生物学调控新途径,开辟植物-土壤-微生物交叉创新领域,根际生命共同体理论创新有助于破解粮食安全、资源高效、环境保护多目标协同的难题,支撑我国农业绿色发展。文章指出了根际生命共同体与养分高效研究的重点方向与内容,尤其是深入揭示和调控植物第二基因组——微生物组的作用正成为农业科学的研究前沿。     

番茄/茄子嫁接对其根际土壤生物学性状及细菌群落结构的影响

以茄子作为砧木,番茄为接穗进行嫁接,并以番茄自根植株和茄子自根植株作为对照,基于传统及现代高通量测序技术分析根际土壤的生物学性状及细菌群落结构特征,旨在揭示嫁接植株抗性增强的机制。结果表明:番茄/茄子嫁接植株根际土壤中可培养细菌、放线菌数量,微生物生物量、酶活性和细菌丰富度、多样性指数均显著高于茄子和番茄自根植株;另一方面,norank_cAcidobacteria、硝化螺菌属(Nitrospira)、芽孢杆菌属(Bacillus)、norank_fGemmatimonadaceae、norank_oGaiellales、norank_fXanthobacteraceae、norank_oSC-I-84、norank_fAnaerolineaceae、norank_fNitrosomonadace...