罗汉果疱叶丛枝病的病原鉴定

在罗汉果Momordica grosvenori Swingle植株上发生一种黄化型病害,病株严重地抑制生长和降低产量。病叶起疱、丛枝,最终叶片黄化。 电镜的超薄切片观察;在病叶叶脉维管束中的薄壁细胞中,有多种形态的类菌质体,直径约为200～800毫微米,可以看到二分裂和生芽的菌体。 在病株中可找到MLO_s,而在健株中的上述组织中未发现。 四环素在特定条件下,可以抑制症状。     

泡桐丛枝病病原的电子显微镜研究

泡桐丛枝病是目前我国泡桐栽培中的一种重要病害,在山东、河南、山西三省尤为严重。济南市以泡桐绿化人行道,丛枝病到处可见。此病属于典型的黄化病害,腋芽和不定芽大量萌发丛生,节间变短,叶片黄化变小、明脉、冬季小枝不脱落,呈现鸟巢状。罹病严     

泡桐丛枝病病原的电子显微镜研究

泡桐丛枝病是目前我国泡桐栽培中的一种重要病害,在山东、河南、山西三省尤为严重。济南市以泡桐绿化人行道,丛枝病到处可见。此病属于典型的黄化病害,腋芽和不定芽大量萌发丛生,节间变短,叶片黄化变小、明脉、冬季小枝不脱落,呈现鸟巢状。罹病严重的当年枯死,轻者几年后也常死掉。泡桐丛枝病能够皮接传播。有关传病媒介正在研     

有关绿矮和黄化复合症的大麦病株电子显微镜研究

1978年秋我们对保定的小麦绿矮和大麦绿矮病株,经超薄切片和抽提后用电子显微镜检查,发现均系由灰飞虱(Laodelphax striatellus Fallen)传播的玉米粗缩病毒(MRDV)所致。在玻璃温室内用灰飞虱传播玉米粗缩病的实验中,还观察到经接种的大麦产生了绿矮和黄化复合症病株。这类病株主要特征是:植株矮化、叶片浓绿肥厚,并有僵直感,有时叶缘缺刻或心叶扭曲,接着心叶渐渐转为黄色,表现出明显的黄化症状。     

我国菊花褪绿斑驳类病毒鉴定

从我国广州地区发现的带有褪绿斑驳症状的“广白”菊花病株中分离到一种小分子核酸,经鉴定其性质与国外报道的菊花褪绿斑驳类病毒(Chrysanthemum Cholrotic Mottle Viroid,ChCMV)的性质完全一致。病株用酚提取后的粗核酸和制备的纯核酸经正反双向或垂直双向聚丙烯酰胺凝胶电泳分析表明为具有单链环状的RNA分子,其分子量与菊花矮化类病毒(Chrysanthemum Stunt Viroid, CSV)的相似。根据病株症状、寄主范围以及分段自我杂交等试验分析,证明这种小分子核酸是类病毒——chcMV,而不是CSV。在检测过程中,我们改进了提取和鉴定类病毒的方法,并建立了可以区分不同种类病毒的分段自我杂交技术。     

我国南方花生发生一种由蕃茄斑萎病毒引起的新病害

我们于1984和1985年6月上、中旬,在广州市郊、县,湛江市郊以及广西南宁市郊、县,北海市郊和合蒲县等花生产区,调查花生病毒病时,除了发现花生轻斑驳病毒病外,还发现一种新的病毒病害。其症状特征是:病株顶端叶片上出现很多褪绿黄斑或环斑,有的环斑变     

陕西小麦梭条斑花叶病(WSSMV)的鉴定研究

陕西关中渭河流域稻麦兼作两熟的小麦高产区的周至、长安和歧山等县,从1974年以来发生一种小麦条纹、丛矮症状的病害,为一种新病害,经初步研究为小麦梭条斑花叶病毒(WSSMV)所引起。一、症状观察在当地最感病品种官村1号上的症状表现是:返青后起身期开始发病,基部叶片现桔黄色斑驳,心叶由尖端退绿黄化,卷起,后沿叶脉显现绿色与淡绿色或黄绿相间并且长短不等的条纹花叶,有时为梭条状花叶(图1)。严重发病早期极其矮化并且大量分蘖,形成丛矮症状。而且花叶症状能随气温升高而逐渐减轻、隐蔽。内部症状是在病叶表皮及其毛状体组织细胞内可检测到非晶体的内含体,稍大于细胞核,近卵园形或不规则形。     

菜豆黄色花叶病毒(BYMV)—新疆苜蓿分离株的鉴定

从新疆苜蓿黄斑花叶病株上分离到病毒分离物M-4,该分离物能引起多种豆科值物系统花叶,并在藜科植物上产生局部褪绿斑,易经汁液摩擦接种和蚜虫传毒,不经菜豆种子传毒。病毒致死温度60—65℃,体外保毒期4—5天,稀释限点10~(-3)—10~(-4)。病毒粒体线状,长约660—740nm,宽15nm;在感病的寄主叶片细胞中,电镜观察到风轮状、带状和环状内含体。免疫电镜法测定,该分离物与菜豆黄色花叶病毒(BYMV)抗血清有血清反应。经SDS-聚丙烯酰胺凝胶电泳和氨基酸自动分析仪分析分别测得该病毒的衣壳蛋白亚基分子量为16,200道尔顿,氨基酸残基数128个。鉴定结果认为,分离物M-4是BYMV的一个株系。     

广西甘薯病毒病的病原病毒种类检测

甘薯病毒病是广西甘薯的主要病害之一。为明确为害广西甘薯的病毒种类,到广西南宁、玉林、崇左、北海、宜州和桂林等市的甘薯种植区采集疑似甘薯病毒病样品,共采集到127个甘薯样品,用为害甘薯的12种病毒的引物,通过RT-PCR或PCR技术检测,并对扩增产物进行测序和所获序列的Blast分析。结果表明:为害广西甘薯的病毒种类有11种,包括10种RNA病毒:甘薯羽状斑驳病毒(sweet potato feathery mottle virus,SPFMV)、甘薯G病毒(sweet potato virus G,SPVG)、甘薯褪绿矮化病毒(sweet potato chlorotic stunt virus,SPCSV)、甘薯轻型斑点病毒(sweet potato mild speckling virus,SPMSV)、甘薯C病毒(sweet potato virus C,SPVC)、黄瓜花叶病毒(cucumber mosaic virus,CMV)、甘薯褪绿斑病毒(sweet potato chlorotic fleck virus,SPCFV)、甘薯脉花叶病毒(sweet potato vein mosaic virus,SPVMV)、甘薯潜隐病毒(sweet potato latent virus,SPLV)、甘薯轻型斑驳病毒(sweet potato mild mottle virus,SPMMV),1种DNA病毒:甘薯卷叶病毒(sweet potato leaf curl virus,SPLCV)。在127份甘薯样品中,有48个样品检测到SPFMV,占37.79%;31个样品检测到SPVG,占24.40%;29个样本检测到SPLCV,占22.83%;27个样本检测到SPCSV,占21.30%,其他被检测到的甘薯病毒占20.00%之下。检测到病毒的88个样品中,有40个样品仅检测到一种病毒,即SPFMV、SPVG、SPCSV、SPMSV、CMV、SPLCV单独侵染。48个样品为2种或2种以上的病毒复合侵染。病毒复合侵染时,甘薯症状表现复杂,有矮化、花叶、皱缩、叶脉突起等症状。其中,检测到SPCSV的甘薯植株,表现出严重的矮化症状。     

柿斑叶蝉的初步研究

柿斑叶蝉(Erythroneura sp.)在山东荷泽地区柿园和零星柿树上普遍发生。1969—1972,1974—1975年我们对此虫做过一些观察。鉴于国内尚未有关于此虫的报道,故将部分结果整理如后。 一、为害和寄主 以成、若虫聚集叶背,初沿叶脉吸食汁液,叶面出现褪绿斑点,叶背无任何症状。以后随着受害加重,斑点密集并遍及整个叶片。至7月中下旬以后被害叶片苍白、上卷,中脉附近的组织变褐。至9月中旬大量脱落,严重影响树势。越冬卵产在当年生枝条的皮层内,也影响树体的正常生理。 通过调查和接虫试验,证实柿斑叶蝉只为害柿树(品种间无差异)。第一代成虫盛发时,有极少数只取食同株柿树上君迁子(Diospyros lotus L.)的叶片,但并不在上面产卵。     

罗汉果疱叶丛枝病的媒介昆虫和防治途径的研究

试验结果指出:棉蚜Aphis gossypii Glov.是罗汉果Siraitia grosvneri(Swingle)Jeffrey.疱叶丛枝病的媒介昆虫。有翅蚜和无翅蚜都有传毒力:传毒习性的研究结果指出:每苗接虫三头或使之吸食15分钟以上,就足以使健苗发病。 由于媒介昆虫自然传播的主导因素.所以理论上和实践上都指出与病区隔离种植实生苗,是解决罗汉果疱叶丛枝病的根本措施之一。     

四环素对多年生草本植物类菌原体病害的施用时间与效果

影响四环素对多年生草本植物的类菌原体病害处理效果的限制因素是蒸腾作用,其中尤以适量的叶片和发达的根系(抗生素营养液处理)是必不可少的。渗透吸收是不能把药液输送到感病植物组织的全部维管束组织中。     

TRANSMISSION AND HOST-RANGE STUDIES OF STRAWBERRY GREEN-PETAL VIRUS

The virus causing phyllody (virescence) in clover flowers was transferred by Cuscuta subinclusa to Fragaria vesca and Duchesnia indica plants which then produced symptoms of strawberry green-petal disease.
The jassid Euscelis plebejus (Fall.) in several forms, including E. lineolatus Brullé, transmitted green-petal virus from clover to clover, to and from a wide range of other hosts, and from but not to strawberry. Two viruses (or strains) were distinguished, one causing phyllody and the other witches' broom on clover; both were retained for more than 2 months by the vector, in which both had a latent period of about 30 days. Macrosteles viridigriseus (Edwards) also transmitted both viruses.
Variation in symptoms on strawberry plants infected naturally, and experimentally through dodder, suggested that two diseases have previously been grouped under the name 'green petal". It is proposed to distinguish these as ( a ) green petal caused by the virus inducing phyllody in clover, and ( b ) bronze leaf wilt caused by the clover witches' broom virus.     

STUDIES IN THE BACTERIAL DISEASES OF SUDAN CROPS

The atypical symptoms first described by Bryan (1932) of the angular leaf spot disease of cotton caused by Xanthomonas malvacearum (E. F. Sm.) Dowson were reproduced by inoculation into seeds, stem apices or buds. The lesions that developed on the veins of the newly produced leaves were elongated and water-soaked, becoming dark brown. The leaf tissue dependent upon infected veins became yellow, flaccid and withered. The development of these symptoms was enhanced when inoculations were made into opening buds or germinating seeds as compared with inoculations into closed buds or dormant seeds.
In other bacterial diseases caused by Xanthomonas spp., somewhat atypical symptoms could also be produced by bud inoculation into the appropriate host. Those produced by X. ricini (Yoshi & Takimato) Dowson on castor, closely resembled the vein lesions described above on cotton but resulted only from bud inoculations; inoculations into stem apices and seeds failed to produce them. In dolichos bean inoculated with X. phaseoli (Smith) Dowson, atypical symptoms were produced only by seed inoculations and were confined to the first simple leaves (prophylls).
The differences in the production of atypical symptoms on the three hosts are correlated with differences in host structure and with the degree of virulence of the pathogen. The leaf parasite X. ricini , for example, which cannot infect castor bean stems, does not produce atypical symptoms when inoculated below the stem apex.
From the data discussed below, the incidence of atypical symptoms is attributed to infection either of an actively growing tissue or of a telescoped structure which subsequently completes its development.
The atypical symptoms of the cotton disease are not caused by a special strain of X. malvacearum. Further, they are not a peculiarity of this disease but may also develop in other necrotic diseases under similar conditions.     

刈割对羊草光合特性影响的研究

 刈割部位不同对羊草光合速率的影响不同。在土壤水分良好条件下,刈割全株之后,长出的再生叶片光合速率显著升高;刈割上位叶之后,残留的下位叶片光合速率有所增加;刈割叶片前部,残留的后部叶片光合速率未见变化。     

类病毒侵染后寄主小麦的细胞学病变

罹种传黄叶枯病的小麦病叶电子显微镜研究证明,无论是病叶的叶肉细胞或筛管、导管。还是病叶的绿色部分或坏死区域均未见有病毒,细菌或任何其它可疑的病原物,病叶绿色部分的细胞的超微结构基本正常,但可见不少细胞的细胞核局部核膜破裂乃至消失,并且核内外物质交流也比正常情况下活跃得多,同时这些细胞胞间连丝直径明显扩大,有的扩大至100nm以上,本文联系类病毒的复制部位和它的转移特点,对这些细胞学病变的生物学意义进行了讨论。     

Isolation and Partial Characterization of Peanut Top Paralysis Virus (PTPV), a Destructive Virus Causing a New Disease in Peanut (Arachis hypogaea L.)

A destructive virus, causing top paralysis to peanut, was discovered in the wild germplasm collection growing in the USDA-ARS greenhouses, Stillwater, Oklahoma, USA. The symptoms observed on the wild plant were restricted to a few leaves as green batches in a light green to yellow background with some leaflets having lost most of the basal part of the laminae leaving the top portion rolling upwards forming a cone. The virus was mechanically transmitted to cultivated peanut ( Arachis hypogaea L,.) where it caused more severe and destructive symptoms including stunting, severe malformation of leaves and partial or complete disappearance of leaflet laminae. This virus differed in symptomology, host range, and/or serological reactivity from allpeanut viruses reported in the literature, particularly those causing leaf malformation and stunting. The virus induced necrotic local lesions on Phaseolus vulgaris L. cv. "Topcrop" and chlorotic local lesions with necrotic centres bordered withvery bright intense red color on Chenopodium amaranticolor. In both passive indirect enzyme-linked immunosorbent assay (PAS-ELISA) and Ouchterlony double immunodiffusion test, the virus did not react with antisera against brome mosaic, bean yellow mosaic, peanut stripe, potato Y, tobacco mosaic, watermelon mosaic 1, watermelon mosaic 2, wheat soilborne mosaic, wheat streak mosaic, and zucchini yellow mosaic viruses.
However, in reciprocal cross reactions the virus seemed to share a common antigenic determinant with a peanut mottle virus isolate from Oklahoma (PMV-OK). The virus had flexuous filamentous particles with a length of 750–850 nm, falling within the range reported for the potyvirus group. The virus was successfully purified and the molecular weight of its protein subunit was found to be 30000 d. A polyclonal antiserum was raised in rabbits against the virus and used for reciprocal serological tests.     

Transmission of the Monocarpic Senescence Signal via the Xylem in Soybean

During monocarpic senescence in soybean (Glycine max [L.] Merrill cv. Anoka) there is a remobilization of nitrogen from the leaves to the seeds, and it has been hypothesized that this loss of nitrogen from the leaves induces foliar yellowing. The phloem in a small segment of the petiole between the pods and the target leaf can be inactivated with a jet of steam. When a plant is depodded except for a single pod cluster in the center of the plant, the pod cluster induces yellowing of the nearest leaf even if the petiole contains a zone of dead phloem, whereas most of the rest of the plant remains green. The nitrogen content of these leaves with a dead phloem zone in their petioles does not decrease greatly, even though the leaves turn yellow. A similar treatment of a single leaf on a fully depodded plant (leaves stay green) does not cause that leaf to turn yellow. Since nutrients would have to be withdrawn from the leaves via the phloem, the pods do not induce yellowing by pulling nutrients out of the leaf and must be able to exert their influence via the xylem.