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1.
以叶色倒置小麦为材料,通过对叶色倒置小麦中倒置茎和正置茎上一些重要的形态、生理和产量等指标的测定及比较.进一步研究小麦叶片非顺序衰老的生物学特性,探讨其理论意义和实践价值.结果表明,倒置茎上旗叶先于倒二叶衰老,与此相呼应,在结实后期旗叶的绿叶面积比<倒二叶绿叶面积比,旗叶叶绿素含量<倒二叶叶绿素含量,伴随这种生理变化下... 相似文献
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将大麦白粉菌(Erysiphe graminis f.sp.hordei)的毒性和无毒性分离菌接接种顺序接种于具有不同抗性基因的大麦品种。不亲和反应所诱导的抗性能降低毒性分离菌的侵染,相反亲和反应诱导的感病性其程度足以增加无毒性分离菌侵染抗性寄主的能力。互作的净效应与单由某一种毒性分离菌接种相比能减少分生孢子的产生最。分离菌之间的每一个互作取决于所采用的寄主品种、病原分离菌和接种次序。先接种无毒性分离菌再接种毒性分离菌常常最易观察到诱导抗性。若先按种毒性分离菌,诱导感病性常常更加明显。不过,在品种Wing上先接种无毒性分离菌,诱导感病性更加明显。在品种Hassan上,先接种毒性分离菌,虽常诱导感病性,但某些时候以先接种无毒性分离菌时诱导更强的感病性。在后一种情况下,尽管无毒性分离菌所致侵染相对较少,但所产生的孢子大多数是由无毒性分离菌形成的。某些事证表明,无毒性分离菌可获得侵染不亲和性寄主的能力。如果没有毒性分离菌的存在,经过几个世代以后这种作用就会消失。 相似文献
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胡杨和灰叶胡杨锈菌夏孢子形态和侵染结构观察 总被引：1，自引：0，他引：1
借助直接观察、显微和超微结构观测等手段,对胡杨和灰叶胡杨锈病显症叶片、锈菌夏孢子的形态、孢子萌发和侵染结构进行了观测。结果表明,胡杨和灰叶胡杨的锈菌夏孢子堆、夏孢子形态结构相似;夏孢子堆散生于叶片正反两面,近半球形或半椭球形,呈橙黄色或金黄色;夏孢子散落分布于叶片正反两面,圆形或卵圆形,透明、橙黄色,厚壁,单胞,表面密生刺瘤;胡杨和灰叶胡杨锈菌夏孢子的长轴和短轴长度、刺瘤高度及刺瘤间距四项指标均无显著性差异;夏孢子萌发产生芽管后形成菌丝,通过叶表气孔直接侵染叶片,以菌丝的形式在叶片组织内扩展。 相似文献
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烟叶采收过程中 ,应注意 5个方面的问题 :一是采收时间。采收工作宜选在早上和上午进行 ,以便识别烟叶的成熟度。旱天采露水烟 ,以利烟叶保湿变黄 ;烟叶成熟后若遇阵雨可立即采收 ,以防返青。若出现返青烟 ,应等其重新落黄后再采收。二是对后发晚熟或贪青晚熟的烟叶 ,应根据其叶龄、叶片弯曲程度适时采收。三是下部叶片采收标准宜低 ,中上部叶片采收标准宜高 ,顶部 3～ 5片烟叶应在充分成熟后一次采收。四是采收时要注意不要采收没有成熟的叶片 ,同时也不要让烟叶过度成熟。此外 ,烟叶采收后不要暴晒和挤压 ,以保证鲜烟叶的质量。五是注意采… 相似文献
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网蝽(Urentiuo hystricellus Richt)对茄子有时产生严重危害。若虫和成虫吮吸植株汁液,使叶片黄萎,降低植株全糖和蛋白质含量。一些普通杀虫剂防治网蝽的效力已经作过实验室试验和小规模田间试验。本文提供拟菊酯类和几种有发展前途的新杀虫 相似文献
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从荷兰进口的百合鳞茎和木屑介质土(保湿材料)中分离到一种滑刃线虫,通过用荷方的百合保湿材料和种球作盆栽生长观察,以及用分离到的该种线虫再回接到盆栽植株上作试验,结果发现:这种滑刃线虫在木屑介质土中能长期生存。生长繁殖4个多月后其线虫群体数量基本不变。该线虫没有自然侵害百合植株。将这种线虫人为接种到百合的花蕾和嫩头上,产生了危害症状,接种在百合叶片上,不能产生危害症状。 相似文献
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ZJUF0986活性代谢产物对稻瘟病菌致病性的影响 总被引：2，自引：1，他引：1
通过菌丝生长速率法和悬滴法测定ZJUF0986活性代谢产物对稻瘟病菌菌丝生长、孢子萌发和附着胞形成的影响。结果表明,ZJUF0986活性代谢产物对稻瘟病菌菌丝生长的有效中浓度EC50为18.55mg/L,与对照药剂三环唑的EC50(17.30mg/L)相比无显著性差异。活性代谢产物不仅影响孢子萌发,也显著降低附着胞的形成。浓度为10mg/L的活性代谢物可完全抑制孢子萌发及附着胞的形成;浓度为1.25mg/L时则明显延缓孢子萌发及附着胞的形成,处理48h后的孢子萌发率和附着胞形成率分别为62.17%和38.46%。以浓度为1.25mg/L活性代谢产物处理的稻瘟病菌孢子悬浮液接种离体大麦叶片,病原菌孢子在大麦叶片表面能部分萌发形成附着胞,但侵染栓形成延迟,致病性明显降低。 相似文献
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非洲特有的水稻黄斑驳病毒病(RYMV)于1966年在肯尼亚维多利亚湖的沃顿勒(Otonglo)首次报导。随后又在塞拉利昂、象牙海岸,尼日利亚,利比亚和坦桑尼亚、桑给巴尔相继报导。发病的典型症状是叶片黄化变色,产生黄色斑驳以及植株矮化。该病由一种直径约为25-30mm的等径病毒引起。易为汁液接种传播,也易为几种叶甲传播。国际热带农业研究所(IITA)和西非 相似文献
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以小麦顺序衰老(正置茎)和非顺序衰老(倒置茎)茎为材料,比较研究了自然天气和干旱条件下小麦正置茎和倒置茎叶片绿叶面积、光合速率、蔗糖磷酸转运酶活性以及地上器官同化物积累和转运特性,旨为进一步研究小麦叶片非顺序衰老的生理生化机制提供思路和理论指导。试验表明:无论是自然天气条件还是干旱条件,温麦19、豫麦19和兰考矮早8倒置茎倒二叶的绿叶面积、光合速率和叶片干重均明显高于旗叶,表现出旗叶早于倒二叶衰老的特征;倒置茎花后同化物转运量、转运率和对籽粒的贡献率、穗重以及叶片蔗糖磷酸合成酶活性均明显高于正置茎。表明小麦叶片的非顺序衰老与花后同化物的快速转运有关,这种衰老方式对小麦籽粒的后期充实是有利的,并且对干旱条件有较强的适应能力。 相似文献
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烟草不同发育阶段对赤星病的抗性表现与综合防治技术 总被引：4，自引：0，他引：4
人工接种结果表明，随着烟叶自下而上逐渐成熟、衰老，抗病性下降。不同抗性类型的品种，其绿色叶片对病害均表现免疫或近免疫，近成熟叶片高抗，成熟衰老叶片表现为感病，与品种田间抗病性结果一致。田间结果表明，采用增施钾肥、适时打顶和下部叶片近成熟期摘除1～3片底脚叶等措施，提高烟草品种抗病性、配合有效的农药品种综合防治烟草赤星病，在重病区布局抗病品种能有效地推迟病害的发生时期，减慢病情的发展速度，且能减少农药施用量和施用次数，减少环境污染。 相似文献
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观赏百合叶枯病症状类型与病原菌鉴定 总被引：3，自引：0，他引：3
引起甘肃省百合叶枯病的主要致病菌为椭圆葡萄孢[Botrytis elliptica(Berk.)Cooker],分离率为70.5%;其次是灰葡萄孢(Botrytis cinerea Peers),分离率为23.0%。该病原菌在不同品种百合叶片上造成的症状有4种类型。不同症状类型病斑分离的病原菌种类不同,其中紫缘黄褐斑型、褐色环纹型和黄缘褐斑型主要致病菌为椭圆葡萄孢,平均分离率为82.5%;叶缘干枯型的主要致病菌为灰葡萄孢,分离率达93.7%。温度为15℃时,易产生菌核;菌核萌发最适温度为15~20℃。 相似文献
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ABSTRACT Spore germination fluid of Alternaria panax, the causal agent of Alternaria blight of American ginseng (Panax quinquefolius), collected from water droplets or aqueous ginseng leaf extracts produced visible water-soaked lesions on wounded, detached leaflets after incubation for 48 h. Maximum development of brown, necrotic spots occurred 4 to 5 days after inoculation on attached and detached ginseng leaflets. Of 15 plant species tested, only American ginseng was susceptible to applications of spore inoculum or spore germination fluid. The phytotoxic activity of the spore germination fluid was destroyed by heat and treatment with proteinase A. The phytotoxic factor was retained by an ultrafiltration membrane with a 30-kDa molecular mass cut-off. Purification of the phytotoxic protein, named AP-toxin, was performed by anion exchange and gel filtration chromatography. Bioactive fractions eluted as a single peak. By comparison with protein standards, a molecular mass of 35 kDa was estimated for the native protein. The denatured protein toxin also had a mass of 35 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Production of the protein toxin was induced on American ginseng leaflets and water extracts of ginseng leaves but not on leaves of other nonhost plants and their water extracts. The results show that A. panax produces a host-specific, proteinaceous toxin during colonization and pathogenesis of ginseng leaves. 相似文献
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落叶松褐锈病[Triphragmiopsis laricinum(Chou) Tai],是由落叶松拟三孢锈菌引起的一种叶锈病。现已知在黑龙江、吉林、辽宁三省的落叶松人工林内,均有不同程度的发生。发病率一般70~80%,重病区可达90%以上。病原菌能为害各种落叶松,以苗期和落叶松人工幼林较为严重。 相似文献
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研究了二氢茉莉酸丙酯(PDJ)对烟草黑胫病的控制作用,结果表明:离体条件下,PDJ对烟草黑胫病Phytophthora parasitica Var. nicotianae的菌丝生长、孢子囊产生、游动孢子释放及萌发均无明显的抑制作用;PDJ处理后显著减轻了烟草幼苗黑胫病的病情,其最佳处理浓度为100 mg/L,最佳处理时间是接种前3 d,持效期在15 d以上;并且PDJ 100 mg/L处理烟苗下部第3片叶后,可使上部未处理叶片病情显著减轻。表明PDJ诱导了烟草幼苗对黑胫病的抗性。 相似文献
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European pear rust induced by the fungus Gymnosporangium sabinae (Dicks) G. causes yellow to bright orange leaf spots on leaves of pear trees. The aim of this study is to identify and quantify polyphenolic compounds found in pear leaf extracts. Identified were: ten hydroxycinnamates, eight flavonols, nine flavan-3-ols and three arbutin derivatives. Polymeric procyanidins were additionally determined by UPLC-FL. The total content of phenolics in the control healthy green leaf extract was 11,889.98 mg but in the infected leaves it reached 28,573.89 mg in the samples with yellow spots and 11,480.06 mg/100 g dry matter (dm) in the green part of leaves. The yellow spots in pear rust leaves were characterized by increased content of flavanol (catechins and procyanidins) and arbutin compounds compared with the green part of the infected leaves and control healthy leaves. 相似文献
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Induced Resistance as a Mechanism of Biological Control by Lysobacter enzymogenes Strain C3 总被引：1，自引：0，他引：1
ABSTRACT Induced resistance was found to be a mechanism for biological control of leaf spot, caused by Bipolaris sorokiniana, in tall fescue (Festuca arundinacea) using the bacterium Lysobacter enzymogenes strain C3. Resistance elicited by C3 suppressed germination of B. sorokiniana conidia on the phylloplane in addition to reducing the severity of leaf spot. The pathogen-inhibitory effect could be separated from antibiosis by using heat-inactivated cells of C3 that retained no antifungal activity. Application of live or heat-killed cells to tall fescue leaves resulted only in localized resistance confined to the treated leaf, whereas treatment of roots resulted in systemic resistance expressed in the foliage. The effects of foliar and root applications of C3 were long lasting, as evidenced by suppression of conidial germination and leaf spot development even when pathogen inoculation was delayed 15 days after bacterial treatment. When C3 population levels and germination of pathogen conidia was examined on leaf segments, germination percentage was reduced on all segments from C3-treated leaves compared with segments from non-treated leaves, but no dose-response relationship typical of antagonism was found. Induced resistance by C3 was not host or pathogen specific; foliar application of heat-killed C3 cells controlled B. sorokiniana on wheat and also was effective in reducing the severity of brown patch, caused by Rhizoctonia solani, on tall fescue. Treatments of tall fescue foliage or roots with C3 resulted in significantly elevated peroxidase activity compared with the control. 相似文献
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A leaf spot disease was found widespread on Bougainvillea in Brunei Darussalam. Leaf spots were characterized by circular to irregular brown necrotic areas with yellow haloes. A non-fluorescent bacterium was isolated consistently from the lesions and confirmed as the causal agent by Koch's postulates. On the basis of biochemical characterization and inoculation tests, the bacterium was identified as Pseudomonas andropogonis. This is the first report of a bacterial disease on bougainvillea in Brunei Darussalam. 相似文献
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2015年春季在昆明市区绿化带种植的中华常春藤上发现一种由细菌侵染而引起的病害,称为中华常春藤细菌性叶斑病。通过发病症状、菌落形态观察、致病性测定、Biolog分析,16S rDNA序列和核糖体DNA内转录间隔区(internal trans-cribed spacer, ITS )序列分析比较,对昆明地区的常春藤叶斑病病原菌及其系统进化关系进行研究。分离病原菌接种中华常春藤叶片完成科赫法则验证,发病初期在叶片表面形成带有黄色叶晕的不规则褐色斑点,后期叶片边缘形成倒V字型坏死并起皱。将菌株CCT1和CCT6测序结果与现有的黄单胞菌菌株的16S rDNA序列和核糖体DNA的ITS序列构建进化树,结果均显示病原菌与野油菜黄单胞菌的序列相似度最大,属于同一支。研究确定该病原菌为野油菜黄单胞菌(Xanthomonas campestris)。这是中国首次报道由X. campestris 引起的中华常春藤叶斑病。 相似文献