Extracts of killedPenicillium chrysogenum Induce resistance against Fusarium wilt of melon     

Hezhong Dong  Yigal Cohen 《Phytoparasitica》2001,29(5):421-430

Dry fungal biomass ofPenicillium chrysogenum (dry mycelium), a waste product of the pharmaceutical industry, was extracted with water and applied to the roots of melon plants before or after inoculation withFusarium oxysporum f.sp.melonis (Font). Seedlings (4–6 days after emergence) treated with either acidic dry mycelium extract (DME) or neutralized dry mycelium extract (NDME) were protected against challenge infection withFom. A single drench with 2–5% DME applied 12–72 h before inoculation provided significant control of the disease compared with water-drenched, challenged seedlings. No protection was seen in plants treated 0–6 h before inoculation or 0–48 h after inoculation. Neither DME nor NDME (0.5–5%) had any effect on fungal growthin vitro, which implied that disease controlin vivo was mediated by induced resistance. The resistance induced by DME protected melon plants not only against race 1,2, but also against the three other races of the pathogen, indicating a race-non-specific resistance againstFom. Both DME and NDME significantly increased peroxidase activity and free L-proline content in seedlings 12 h and 48 h after soil drench, respectively. Resistance to Fusarium wilt was significantly associated with elevated levels of peroxidase activity but not with free L-proline content. Thus, peroxidase might be involved in the defense mechanisms activated by DME or NDME. http://www.phytoparasitica.org posting Aug. 31, 2001.  相似文献   

小麦白粉病菌闭囊壳萌发及其对三唑酮敏感基线的建立   总被引：9，自引：0，他引：9  

袁善奎  马严明  周明国 《植物保护》2001,27(1):1-3

在没有甾醇脱甲基抑制剂 (DMI)类药剂用药历史的湖北利川山区麦田采集小麦白粉病菌闭囊壳 ,带回室内萌发 ,从每样本单孢子堆中分离得到61个野生菌株。采用叶段法测得每个菌株的EC₅₀,建立起小麦白粉病菌对三唑酮的相对敏感基线EC₅₀=(0.1090±0.0048)μg/ml。  相似文献   

林间释放平腹小蜂防治银杏大蚕蛾研究   总被引：4，自引：1，他引：4  

吴猛树  杜友兵等 《昆虫天敌》2001,23(1):26-29

笔者于1999－2000年在城口银杏大蚕蛾发生区释放用其卵繁育的平腹小蜂防治银杏大蚕蛾，结果表明：放蜂区虫卵寄生率明显提高，其校正寄生率为69.30%，是一种可利用的天敌昆虫。可在银杏大蚕蛾发生区内推广应用。  相似文献   

抗性品种与天敌对褐稻虱种群的协同调节作用   总被引：5，自引：0，他引：5  

高春先  贝亚维  顾秀慧 《植物保护学报》1992,19(4):317-322

褐稻虱(Nilaparvuta lugens)是我国水稻的主要害虫。以往的粳稻品种,感褐稻虱;近几年来一系列抗褐稻虱品种如秀水620、秀水664已经育成,1990年已种植150万亩。种植抗性品种可少用或不用杀虫剂,能大量保存天敌,抗性品种与天敌的协同作用,对控制褐稻虱种群,改善防治策略,具有现实意义。该文报道了田间和实验室观察调查多种天敌的数量和捕食或寄生效果,估计了在不同抗感品种上褐稻虱种群趋势指数1值,并分析了粳稻抗性品种与蜘蛛类抑制褐稻虱的协同作用。  相似文献   

氟乐灵处理后棉苗对枯萎病菌的抗侵入及抗扩展特性     

宋凤鸣  郑重 《植物病理学报》1995,25(4):335-340

 以1μg/g土的氟乐灵播前土壤处理,棉花出苗后移栽到无氟乐灵的土壤中并接种棉花枯萎病菌(Fusarium axysporum f.sp.vasinfectum)。结果表明氟乐灵处理明显降低了棉苗枯萎病的株发病率和病情指数,提高了棉苗对枯萎病的抗病性。氟乐灵处理组棉苗根部和茎部枯萎病菌侵染率均低于对照组,特别是上部茎片段中处理组侵染率降低更为明显。氟乐灵处理组棉苗根部和茎部的菌量明显降低,而且处理组茎部菌量的增长明显滞后于对照。以上结果表明,病菌对氟乐灵处理棉苗根部的侵入和病菌在棉苗体内的纵向扩展及增殖受到了阻抑,因而氟乐灵处理后棉苗对枯萎病菌的抗性表现了抗侵入和抗扩展的特性。试验还证明,氟乐灵处理并接种病菌的棉苗茎部组织中类萜烯醛的含量明显提高;并产生一种能抑制病菌大型分生孢子萌发的真菌毒性物质。这些抑菌物质的产生和积累可能与抗扩展特性有关。  相似文献   

小麦白粉病菌越夏,越冬和春季菌源毒性结构比较     

王锡锋  张忠山 《植物病理学报》1995,25(4):301-305

 分析了1992年和1993年不同时期采集的小麦白粉病菌越夏、越冬和春季菌源共238个菌株的生理小种、毒性基因结构和对9个推广品种的毒力频率。结果表明三种菌源在生理小种和毒性基因组成及出现频率是相似的,对9个推广品种的毒力频率均较高。这样在白粉病菌毒性和品种抗病性研究中,可以采集应用越夏和越冬菌株标样,避免了夏季高温季节保存菌株的工作;而且从毒性结构方面进一步证实白粉病菌主要以分生孢子在夏季侵染高海拔地区的自生麦苗而越夏,再逐渐扩展至秋播麦苗越冬后导致春季大田发病,病菌的子囊孢子在平原地区侵染循环上作用不大。  相似文献   

Different effects of NaCl on activities of transglutaminases from marine and freshwater shellfish muscles     

Hisanori Nozawa  Takashi Mori  Nobuo Seki 《Fisheries Science》2001,67(2):383-385

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New potyvirus isolated from <Emphasis Type="Italic">Cryptotaenia japonica</Emphasis>     

Kentaro Okuno  Tomoko Hama  Minoru Takeshita  Naruto Furuya  Yoichi Takanami 《Journal of General Plant Pathology》2003,69(2):138-142

 A potyvirus, for which the name Japanese hornwort mosaic virus (JHMV) is proposed, was isolated from Japanese hornwort plants (Cryptotaenia japonica) with mosaic disease symptoms. The virus was used to inoculate mechanically 34 plants belonging to 33 species of 10 families. Of these species seven from two families were infected. Faint chlorotic spots appeared on the inoculated leaves of Chenopodium quinoa and C. amaranticolor, but no systemic infection occurred in these plants. JHMV systemically infected only Umbelliferae plants; they did not infect 26 other species in eight families. JHMV was transmitted in a nonpersistent manner by aphids (Myzus persicae). The virus was a flexuous rod-shaped particle about 750 nm in length. Sequencing the nucleotides in the 3′ terminal region of JHMV revealed that the coat protein contains 280 amino acids with a molecular mass of 32.2 kDa. The nucleotide sequence of the coat protein of JHMV had the highest similarity with that of Zantedeschia mosaic virus (83.3%) compared to those of other potyviruses (57.0%–64.9%). An antiserum against JHMV reacted strongly with JHMV and weakly with Potato virus Y. These results indicate that JHMV is a new potyvirus. Received: September 9, 2002 / Accepted: November 7, 2002 RID="*" ID="*" The nucleotide sequence determined in this work appears in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB081518  相似文献   

Induced resistance in cotton seedlings against fusarium wilt by dried biomass of<Emphasis Type="Italic">Penicillium chrysogenum</Emphasis> and its water extract     

Hezhong?Dong  Yigal?CohenEmail author 《Phytoparasitica》2002,30(1):77-87

Dry mycelium (DM) of killedPenicillium chrysogenum and its water extract (DME) were used to induce resistance in cotton plants againstFusarium oxysporum f.sp.vasinfectum (Fov). Results showed that the efficacy of either DM or DME in controlling the disease depends on both the concentration and the mode of application. DM amended to the soil at 0.25–2% (w/w) provided 32–75% protection againstFov. Soil drench with 2–5% DME (w/v) and pre-sowing seed soakage with 5–10% DME provided 51–77% and 28–35% protection against the wilt disease, respectively, whereas no protection was obtained with foliar sprays of 1–10% DME. DM and its water extract had no direct antifungal activity on growth ofFov in vitro, suggesting that disease control with DM or DME resulted from the induction of natural defense mechanisms in the cotton plants. Soil drench with 5% DME was as effective as 2% DM powder in inducing resistance againstFov, implying that the resistance-inducing substances were mostly water-soluble. Four cotton cultivars with various genetic resistance levels againstFov were tested at the seedling stage: two resistant ‘Pima’ cultivars and two susceptible ‘Acala’ cultivars. The level of protection achieved in the two susceptible cultivars with DME was equal to, or higher than, that of the two resistant cultivars treated with water. Innate and induced peroxidase activity in cotyledons or hypocotyls and roots coincided with the level of genetic resistance and DME-induced resistance, respectively. Based on our results, an integrated control strategy ofFov with both genetic resistance and induced resistance is suggested.  相似文献   

辽东半岛结缕草无性系种群构件生物量相关模型及形成规律   总被引：5，自引：2，他引：5  

张学勇  杨允菲  张殿顺  张绵 《草原与草坪》2006,(3):23-26

按生物构件的理论,分析了辽东半岛结缕草无性系种群叶片、叶鞘、分株、匍匐茎各构件生物量以及总生物量间的相关模型和构件生物量的分配、形成规律,探讨了其不同生物量基于种群大小(密度)的形成规律。结果表明,辽东半岛结缕草无性系种群的总生物量及各构件生物量均随着种群密度的增大而以线性函数增加,各构件生物量与总生物量以及各构件生物量间亦均以线性函数增加,生物量增加比率均表现为:分株>匍匐茎,叶鞘>叶片,总生物量增量的27.2%分配给叶片,29.2%分配给叶鞘,43.6%分配给匍匐茎,叶片,叶鞘和匍匐茎构件生物量的积累是按1∶1.1∶1.6比例形成。  相似文献