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水稻干尖线虫引起"小粒翘穗"症状的观察 总被引:2,自引:0,他引:2
水稻干尖线虫(AphelenchoidesbesseyiChristie)为害水稻引起的典型症状,是在水稻孕穗期上部叶片的尖端2~4cm处形成扭曲状干尖,这是作为病害田间诊断的主要依据。对高秆散穗型品种,这种症状表现十分明显。近年来淮安市水稻品种更换为矮秆密穗型品种后,干尖线虫病仍有发生,但干尖现象不明显,田间大量出现“小粒翘穗”现象。对这一现象我们进行了田间观察及对病稻粒进行了分离检测,结果从病稻粒中分离出了水稻干尖线虫。据此,我们初步认为“小粒翘穗”为水稻干尖线虫病所致。1“小粒翘穗”发生情况水稻干尖线虫病是江苏省水稻一种常见的种传… 相似文献
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干旱胁迫对不同穗型超级稻品种产量及穗部性状的影响 总被引:4,自引:1,他引:3
通过水分仪结合称重法的盆栽试验,在水稻幼穗分化至灌浆结实的不同时段,人为控制土壤水分以模拟干旱胁迫的发生,研究了中度干旱胁迫对不同穗型超级稻品种产量因素及穗部性状的影响。结果表明:不同时段的中度干旱胁迫对水稻产量及穗部性状都有影响,最终籽粒产量均比正常供水时显著下降,穗分化15~30 d控水处理影响最大,其次是开花至花后15 d和花后15~30 d的控水处理,减产原因主要是结实率下降和千粒重降低。不同品种受影响的程度有所不同,超级稻品种较普通杂交稻品种来说相对要小,但也有受影响较大的超级稻品种,大穗型品种(国稻6号、两优培九、Ⅱ优7号)受干旱胁迫的影响程度要低于中穗型品种(天优998、Ⅱ优602、汕优63)。 相似文献
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正根据多年的田间调查,临沭县小麦主要病害有:白粉病、纹枯病、黄花叶病、赤霉病、锈病、线虫病。下面将这几种病害在我县的危害症状与防治技术介绍如下:1白粉病1.1为害症状白粉病在苗期至成株期均可发病。主要为害叶片,严重时也可为害叶鞘、茎秆和穗部。茎和叶鞘受害后,植株易倒伏。发病严重时植株矮小细弱,穗小粒少,千粒重明显下降,严重影响产量。冬季温暖、雨雪较多,土壤湿度较大,有利于病原菌越冬;春季降雨较多,阴天多,病害发生较 相似文献
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一、稻曲病在我县的发生概况及其危害: 稻曲病是在我县近年来新发生的一种水稻病害。该病始见于一九七七年城关镇城北大队从福建引入的大穗型品种“千粒串”上,1978年城关镇三二五大队岳家庄生产队试种的“江南矮”感病严重。此后相继在广东引入的“桂朝二号”和推广的“汕优2号”品种上发病。1980年三标公社“桂朝二号”, 相似文献
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小麦穗组织中脱氧镰刀菌烯醇毒素的免疫细胞化学定位 总被引:5,自引:0,他引:5
采用免疫细胞化学技术对禾谷镰刀菌(Fusarium graminearum)在侵染小麦穗部过程中产生的脱氧镰刀菌烯醇毒素(deoxynivalenol,DON)进行了定位分析。在接种后24h,当菌丝在外稃、内稃的内侧表面扩展而尚未侵入寄主细胞前,病菌已分泌DON,并且DON已扩散到寄主组织内。在菌丝细胞内,DON主要被定位于细胞质、线粒体及细胞壁上;在寄主细胞中DON主要分布于细胞壁、叶绿体、细胞质和内质网上。在侵染初期(接种后2 d),菌丝仅能在寄主细胞间隙扩展,随寄主组织中DON浓度的升高,寄主细胞相应发生了一系列病理变化。随寄主细胞坏死(接种后3~4d),病菌进入坏死的寄主细胞。上述结果表明,DON在禾谷镰刀菌的侵染、致病和定殖过程中起着重要的作用。毒素标记结果表明病菌产生的毒素可通过穗轴微管束组织从侵染部位向上、向下转输,毒素向上的转输量明显高于向下转输 相似文献
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禾谷镰刀菌侵染引致小麦穗组织细胞壁成分变化的细胞化学研究 总被引:1,自引:0,他引:1
本文采用细胞化学方法, 对健康和禾谷镰刀菌(Fusarium graminearum)侵染的小麦穗组织中细胞壁主要成分进行了比较分析。电镜观察发现, 被侵穗部组织细胞壁中的主要成分如纤维素、木聚糖和果胶质的标记密度下降, 显著低于未接种的健康对照组织。结果表明病菌侵染和扩展过程中分泌产生了纤维素酶、木聚糖酶和果胶酶等细胞壁降解酶类, 造成寄主细胞壁成分的分解及细胞壁松弛, 从而有利于病菌在寄主穗部组织中的侵染和扩展。 相似文献
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禾谷镰刀菌在小麦穗部侵染过程的细胞学研究 总被引:8,自引:0,他引:8
采用扫描和透射电镜技术系统地观察了禾谷镰刀菌(Fusarium graminearum)在小麦穗部的侵染过程。接种后6~12 h,分生孢子在小麦穗部的任何部位均可萌发,每个孢子可产生1至多个芽管,新产生的芽管并不立即入侵寄主组织,而是在寄主体表生长扩展;接种后36~48 h观察,小穗颖片、外稃、内稃的内侧和子房的表面形成了密集的菌丝网,然而在小麦穗轴表面、颖片和内稃的外表面,菌丝生长缓慢、分布稀疏,但颖片外表边缘的菌丝可跨越边缘扩展到颖片的内表皮上;接种后36 h,寄主体表菌丝产生入侵菌丝,以直接入侵方式由颖片、外稃、内稃的内侧及子房的顶部侵入寄主组织体内,随后,菌丝以胞间和胞内生长的方式向下扩展;接种后4~5 d,菌丝由上述组织扩展到达穗轴后,在穗轴内沿微管束组织和皮层组织向上和向下扩展,延伸到相邻小花,随菌丝在小麦穗部组织内不断地生长扩展,使得寄主细胞坏死、解体,并最终导致整个麦穗的枯死。 相似文献
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临清市地处鲁西北平原,种植作物以小麦、玉米为主,小麦常年种植面积50 000 ha 左右。2018 年,临清市小麦白穗现象比较普遍,70%以上麦田发病,一般病株率8%~15%,严重田块达到30%以上,造成比较严重的减产。根据症状判断白穗主要由小麦茎腐病、根腐病、纹枯病、全蚀病以及小麦赤霉病引起。 相似文献
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The infection process of Fusarium avenaceum on wheat spikes and the alteration of cell wall components in the infected host tissue were examined by means of electron microscopy and cytochemical labelling techniques following spray inoculation at growth stage (GS) 65 (mid-flowering). Macroconidia of the pathogen germinated with one to several germ-tubes 6–12 h after inoculation (hai) on host surfaces. The germ-tubes did not penetrate host tissues immediately, but extended and branched on the host surfaces. Hyphal growth on abaxial surfaces of the glume, lemma and palea was scanty 3–4 days after inoculation (dai) and no direct penetration of the outer surfaces of the spikelet was observed. Dense mycelial networks formed on the inner surfaces of the glume, lemma, palea and ovary 36–48 hai. Penetration of the host tissue occurred 36 hai by infection hyphae only on the adaxial surfaces of the glume, lemma, palea and upper part of ovary. The fungus penetrated the cuticle and hyphae extended subcuticularly or between the epidermal wall layers. The subcuticular growth phase was followed by penetration of the epidermal wall, and hyphae spread rapidly inter- and intracellularly in the glume, lemma, palea and ovary. During this necrotrophic colonization phase of the wheat spike, a series of alterations occurred in the host tissues, such as degeneration of cytoplasm and cell organelles, collapse of host cells and disintegration of host cell walls. Immunogold labelling techniques showed that cell walls of spike tissues contained reduced amounts of cellulose, xylan and pectin near intercellular hyphae or infection pegs compared to walls of healthy host tissues. These studies suggest that cell wall degrading enzymes produced by F. avenaceum facilitated rapid colonization of wheat spikes. The different penetration properties of abaxial and adaxial surfaces of the spikelet tissues as well as the two distinct colonization strategies of host tissues by F. avenaceum are discussed. The penetration and colonization behaviour of F. avenaceum in wheat spikelets resembled that of F. culmorum and F. graminearum, although mycotoxins produced by F. avenaceum differed from those of the latter two Fusarium species. 相似文献
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S. K. Raj S. K. Snehi M. S. Khan M. H. Asif S. K. Bag R. K. Roy A. K. Goel 《Journal of General Plant Pathology》2010,76(6):389-394
In 2007–2009, severe virescence, malformation and twisting of flower spikes and yellowing of entire plants were observed in
various Gladiolus cultivars growing in the gardens of the National Botanical Research Institute, Lucknow, India. The disease symptoms were
very similar to symptoms in Gladiolus caused by the Aster yellows phytoplasma identified from Poland. Disease incidence was low (1.1–3.4%), but the severity of
symptoms was high. A phytoplasma infection was detected in nine of 13 cultivars by PCR followed by nested PCR using universal
phytoplasma primers P1/P6 or R16F2n/R16R2, respectively. An amplicon of ~1.2 kb obtained from the nested PCR was cloned and
sequenced. Sequence analysis of the PCR amplicon revealed high (94–98%) identities and the closest phylogenic relationships
with several isolates of Aster yellows phytoplasma of ‘Candidatus Phytoplasma asteris’ (16SrI group). Thus, the phytoplasma isolate of Gladiolus was identified as a new isolate of ‘Ca. P. asteris’ (16SrI group). In silico analysis of the phytoplasma isolate clearly indicated that the isolate was distinct
from other Indian isolates of this phytoplasma. 相似文献
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B. Qu H. P. Li J. B. Zhang Y. B. Xu T. Huang A. B. Wu C. S. Zhao J. Carter P. Nicholson Y. C. Liao 《Plant pathology》2008,57(1):15-24
A large number of Fusarium graminearum and F. asiaticum isolates were collected from wheat spikes from all regions in China with a history of fusarium head blight (FHB) epidemics. Isolates were analysed to investigate their genetic diversity and geographic distribution. Sequence characterized amplified region (SCAR) analyses of 437 isolates resolved both species, with 21% being F. graminearum (SCAR type 1) and 79% being F. asiaticum (SCAR type 5). AFLP profiles clearly resolved two groups, A and B, that were completely congruent with both species. However, more diversity was detected by AFLP, revealing several subgroups within each group. In many cases, even for isolates from the same district, AFLP haplotypes differed markedly. Phylogenetic analyses of multilocus DNA sequence data indicated that all isolates of SCAR type 1, AFLP group A were F. graminearum , whilst isolates of SCAR type 5, AFLP group B were F. asiaticum , demonstrating that it is an efficient method for differentiating these two species. Both species seem to have different geographic distributions within China. Fusarium graminearum was mainly obtained from wheat growing in the cooler regions where the annual average temperature was 15°C or lower. In contrast, the vast majority of F. asiaticum isolates were collected from wheat growing in the warmer regions where the annual average temperature is above 15°C and where FHB epidemics occur most frequently. This is the first report of the distribution of, and genetic diversity within, F. graminearum and F. asiaticum on wheat spikes throughout China. 相似文献
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采用电镜技术研究了三唑类杀菌剂戊唑醇(tebuconazole)对赤霉病菌Fusarium gramineaum侵染小麦穗部过程的影响.结果表明:人工接种前2天施药,可推迟外稃内表皮、内稃及子房上分生孢子的萌发,但不能完全抑制其萌发,可引起芽管和菌丝严重畸形,不能形成侵染菌丝侵入寄主.而人工接种后2天施药,戊唑醇则严重抑制了病菌菌丝的生长,使寄主体表和寄主组织内的菌丝形态、结构发生了一系列异常变化,并最终塌陷死亡,使菌丝不能扩展到穗轴部位.接种后4天施药,病菌虽已扩展到穗轴,但戊唑醇仍对穗轴中菌丝生长具有明显的抑制作用.对赤霉毒素的免疫细胞化学标记结果表明,药剂处理与未处理的寄主和菌丝细胞中都存在有毒素,但标记密度在药剂处理的寄主和菌丝细胞中明显低于未处理对照. 相似文献
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Pathogen development and host responses in wheat spikes of resistant and susceptible cultivars infected by Fusarium culmorum causing Fusarium head blight (FHB), were investigated by means of electron microscopy as well as immunogold labelling techniques. The studies revealed similarities in the infection process and the initial spreading of the pathogen in wheat spikes between resistant and susceptible cultivars. However, the pathogen’s development was obviously more slow in the resistant cultivars as in comparison to a susceptible one. The structural defence reactions such as the formation of thick layered appositions and large papillae were essentially more pronounced in the infected host tissues of the resistant cultivars, than in the susceptible one. β -1,3-glucan was detected in the appositions and papillae. Furthermore, immunogold labelling of lignin demonstrated that there were no differences in the lignin contents of the wheat spikes between susceptible and resistant cultivars regarding the uninoculated healthy tissue, but densities of lignin in host cell walls of the infected wheat spikes differed distinctly between resistant and susceptible cultivars. The lignin content in the cell walls of the infected tissues of the susceptible wheat cultivar increased slightly, while the lignin accumulated intensely in the host cell walls of the infected wheat spikes of the resistant cultivars. These findings indicate that lignin accumulation in the infected wheat spikes may play an important role in resistance to the spreading of the pathogen in the host tissues. Immunogold labelling of the Fusarium toxin DON in the infected lemma showed the same labelling patterns in the host tissues of resistant and susceptible cultivars. However, there were distinct differences in the toxin concentration between the tissues of the susceptible and resistant cultivars. At the early stage of infection, the labelling densities for DON in resistant cultivars were significantly lower than those in the susceptible one. The present study indicates that the FHB resistant cultivars are able to develop active defence reactions during infection and spreading of the pathogen in the host tissues. The lower accumulation of the toxin DON in the tissues of the infected spikes of resistant cultivars which results from the host’s defence mechanisms may allow more intensive defence responses to the pathogen by the host. 相似文献