马铃薯防御酶系活性与其抗晚疫病的关系

应用比较生理学方法,以6个对晚疫病抗性不同的马铃薯品种为材料,研究无病原菌浸染及病原菌浸染后抗、感病品种的马铃薯叶片中防御酶系活性的变化与其抗晚疫病的关系。结果表明:无病原菌浸染及病原菌浸染后,抗病品种比感病品种有较高的PPO、POD和-β1,3-葡聚糖酶活性。因此认为PPO、POD和-β1,3-葡聚糖酶活性与马铃薯抗晚疫病有关。另外,接种后各指标测定结果均不同程度地高于无病原菌浸染时期,表明病原菌浸染后诱导马铃薯体内与抗晚疫病有关的防御酶活性升高。本研究从防御酶活性变化方面阐明马铃薯抗病的生理基础,为马铃薯抗病生理选种提供理论依据。     

Effects of Mulch and Potato Hilling on Development of Foliar Blight (<Emphasis Type="Italic">Phytophthora infestans</Emphasis>) and the Control of Tuber Blight Infection

Foliar and tuber blight caused by Phytophthora infestans accounts for significant losses in potatoes in field and storage. Nevertheless, limited research has been published on the effects of cultural practices on late blight control. Field experiments were conducted in two years on Howard gravely loam soil in New York State to evaluate the effectiveness of mulching using oat straw and hilling in preventing tuber blight infection for cvs Allegany and Katahdin. Potato hilling and mulching had little effect on foliar blight development. The cultivar affected the disease development in the foliage, with cv. Allegany showing lower foliar late blight than cv. Katahdin. Tuber blight incidence averaged 25% for cv. Allegany and 3% for cv. Katahdin in hilled plots, while in the mulched plots the incidence of tuber blight averaged 33% for cv. Allegany and 10% for cv. Katahdin. The straw hay mulch was ineffective in tuber blight control. Tubers set at a soil depth of more than 7 cm had lower tuber blight incidence than shallow tubers set at a depth of less than 7 cm. In both years, hilling provided partial protection of tubers but its effectiveness was limited in the presence of favourable conditions for late blight development. Even though large hills had proportionally a lower tuber blight incidence than medium-sized hills, the difference between the different hill sizes was not significant. These studies suggest that the use of cultivars with foliage resistance to late blight in combination with cultural practices may partially reduce the incidence of tuber blight. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation for endorsement by Cornell University or the US Department of Agriculture.     

不同培养条件对循化线辣椒疫霉菌产孢量的影响

[目的]探讨不同培养条件对循化线辣椒疫霉病产孢量的影响。[方法]针对光照时数、pH、培养基以及温度对循化线辣椒疫霉菌分离培养过程中产孢量的影响进行了研究。[结果]循化线辣椒疫霉菌在24 h/天光照、pH为7.0、马铃薯培养基（PSA）和30℃条件下产孢量最大,其中pH、基础培养基和温度对产孢量影响较大。[结论]为循化线辣椒在自然界发病条件方面的研究奠定了基础。     

马铃薯晚疫病菌抗药性研究现状

由于马铃薯晚疫病菌对常用杀菌剂产生抗药性,降低了化学防治晚疫病的效果,对马铃薯晚疫病的化学防治药剂及晚疫病菌抗药性的研究进展进行了综述,建议生产上应避免长期使用单一的杀菌剂,应与其它无交互抗性的药剂交替使用或混合使用,以避免或延缓抗药性的产生。     

6种杀菌剂对马铃薯晚疫病菌的室内毒力测定

采用菌落直径法测定了金雷多米尔、杀毒矾、克露、克霜氰、大生M-45和进富6种杀菌剂对马铃薯晚疫病菌的毒力。结果表明供试的6种杀菌剂对马铃薯晚疫病菌丝生长都有较好的抑制作用,克露对晚疫病菌毒力最强,其EC50值为0.16μg·mL-1,毒力最差的是大生,其EC50值为2.89μg·mL-1,其余4种药剂按毒力大小依次为克霜氰、金雷多米尔、进富和杀毒矾,其EC50值分别为0.24μg.mL-1、0.28μg·mL-1、0.43μg·mL-1和1.17μg·mL-1。根据室内毒力测定结果及药剂特性,供试的6种杀菌剂在生产上可视病害的发生情况交替使用,以避免或延缓抗药性的产生。     

烟草疫霉侵染后剑麻H.11648叶片细胞超微结构和防御酶活性研究

斑马纹病是剑麻的主要病害之一,本研究以剑麻斑马纹病高感品种H.11648为材料,分别在接种烟草疫霉0、24、36、48、72 h取样,用电镜观察H.11648叶片细胞超微结构变化,同时分析过氧化氢酶(CAT)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)等防御酶活性变化情况。结果表明：H.11648在接种24 h,可见大量休止孢,叶绿体结构被破坏,植物组织开始降解,随着时间延长,附着孢出现,吸器形成,植物组织解体更严重,接种72 h,可见大量菌丝。在整个接种过程中,CAT、PAL和PPO活性显著增强,72 h达到最高,分别为501.44、25.73、1 742.67 U/(g.min)。SOD和APX活性显著下降,72 h达到最低,分别为2 888.62 U/g和841.96 μmol/(g.min)。POD活性先下降72 h又上升,但均显著低于接种前POD活性。本研究从细胞学和生理水平为探讨剑麻与烟草疫霉互作关系提供了理论基础。     

嗜线虫致病杆菌代谢物拮抗大豆疫霉

测定嗜线虫致病杆菌（Xenorhabdus nematophilus）发酵液对大豆疫霉（Phytophthora sojae）菌丝生长、孢子囊形成及萌发的影响，采用种子和土壤处理的方法研究了发酵液对幼苗发病率的作用。结果表明：发酵液对大豆疫霉（Phytophthora sojae）菌丝生长有较强的抑制作用，50ml/L发酵液能完全抑制菌丝的生长，6ml/L发酵液的抑制率仍达68.86%；发酵液能强烈抑制大豆疫霉的孢子囊形成，10ml/L-100ml/L的发酵液处理孢子囊8天后的抑制率分别达97.04%和99.19%，5ml/L发酵液仍达到82.74%的抑制率；发酵液对孢子囊的萌发有一定抑制作用，处理后48小时，6ml/L-100ml/L发酵液的抑制率达72.94%－88.56%；发酵液浸种结果表明，发酵液浓度为25ml/L-50ml/L对大豆种子萌发均没有显著影响。用浓度为50ml/L的发酵液处理种子，播种后9天，病株减退率可达79.8%，但12天调查，病株减退率仅达34.4％。发酵液处理带菌土壤能有效减轻大豆幼苗的发病率，50ml/L发酵液处理的病株减退率为76.3%，化学农药甲霜灵处理的病株减退率为84.0%。     

Stability of late blight resistance in population B potato clones

Summary Increased virulence associated with fungicide resistance and variablePhytophthora infestans populations has been recorded in many potato growing regions with enormous economic effects. The current emphasis on disease management in East Africa includes the use of potato varieties with durable resistance to late blight. Seven promising clones from Population B with quantitative resistance (no R-genes), two advanced clones from Population A (with Rgenes) and three control varieties were grown for three cropping seasons in order to determine their reaction and stability of late blight resistance. Late blight occurrence was detected in all cropping seasons. The analysis of variance of disease data (AUDPC) for genotypes, locations x seasons was highly significant (P<0.001) indicating the differential response of the geno-types and the need for stability analysis. The Additive Main Effects and Multiplicative Interaction (AMMI) statistical model, showed that the most stable genotypes were 392127.256, 381471.18, 387121.4 (resistant) and 391049.255 (susceptible to late blight). Within environments, the ranking of genotypes was not consistent. The variety Kabale was ranked as the most susceptible genotype while clone 381471.18 and Rutuku were ranked the most resistant. Selective deployment of resistant and stable varieties is critical in minimizing economic loss and damage attributed to late blight in low input farming systems.     

甘肃马铃薯晚疫病病菌交配型及对甲霜灵的敏感性

检测了2007—2009年在甘肃省采集分离的马铃薯晚疫病菌的交配型及其对甲霜灵的敏感性。79株晚疫病菌进行交配型检测结果表明,69株为A1交配型,4株为A2交配型,6株为自育型;117株马铃薯晚疫病菌对甲霜灵敏感性检测结果为:60.68%的菌株对甲霜灵表现高抗,11.97%表现中抗,27.35%表现敏感。     

三种橡胶树乙烯利刺激剂对柑桔褐腐疫霉的毒力测定

通过含毒介质和橡胶叶片接种的试验方法,测定三种不同载体的乙烯利涂剂(含2％乙烯利)对柑桔褐腐疫霉的抑菌率,结果表明三种乙烯利涂剂均有不同程度的抑菌能力,其中抗病增胶灵抑菌能力最高,效能稳定,持效期长;而以淀粉和甲基纤维素为载体的涂剂抑菌能力较低,效能不稳定,持效期短。