玉米疯顶病种子传播研究   总被引：2，自引：0，他引：2  

杨建国  金晓华  谢爱婷  王晓鸣  朱振东 《中国植保导刊》2002,22(6):3-4

连续3a对不同来源的玉米种子,利用显微镜镜检和试种观察植株发病显症的方法,检测其携带玉米疯顶病病菌状况。结果表明,病株病穗籽粒、病株健穗籽粒、病田健株籽粒都有较高的带菌率。因此,病菌随种子调运远距离传播是造成各地病害突发的主要原因。  相似文献   

根癌农杆菌介导绿色荧光蛋白基因转化印度酸桔的研究   总被引：14，自引：0，他引：14  

石玮  李东栋  邓秀新  伊华林 《园艺学报》2002,29(2):109-112

 通过根癌农杆菌介导将绿色荧光蛋白基因转入印度酸桔的胚性愈伤组织中, 经潮霉素筛选,获得抗性愈伤组织, 并再生植株。对这些植株进行GUS 染色、PCR 分析、绿色荧光检测和Sourthern 杂交验证, 结果表明绿色荧光蛋白已经在转基因植株中表达。  相似文献   

A reactive pattern of ischemia-induced nestin protein in the rat brain     

LEI Wan-long  YUAN Qun-fang  DONG Zhi-hong  YAO Zhi-bin 《园艺学报》2002,18(6):639-642

AIM:To explore the expressive profile of nestin protein in the focal ischemic brain and to study the recovery mechanism of brain focal infarct.METHODS:Cellular morphology,time-course and distribution pattern of nestin positive response were immunohistochemically examined in different brain regions of 36 adult male SD rats. RESULTS:Nestin positive response of different brain regions in sham operated rats was present in small- and micro-vasculartures and the third ventricle bottom and ependyma. A large number of nestin positive cells were detected in ischemic brain, and were more remarkable in the cortical areas of parietal lobe and preoptic area as well as ischemic caudoputamen. Stellate nestin positive cells were located in the deep layer of ischemic cortex, but fibrillary cells were located in the shallow layer. Nestin positive cells in the ischemic caudoputamen showed the same changes of morphology as those cells in the deep layer of ischemic cortex. Morphological and number alterations of nestin positive cells were the most remarkable at 1 weeks post-ischemia, which showed more hypertrophy and proliferation in morphology, and a marked increase in number was present in the ischemic cerebral cortex and the ischemic caudoputamen. These alterations of nestin positive cells persisted up to 6 weeks post-ischemia, and then, the nestin positive response in the ischemic brain decreased gradually.CONCLUSION:Focal cerebral ischemia induces nestin re-expression on reactive astrocytes, which may be very important to the self-recovery of cerebral infarct.  相似文献   

Variation of Parthenium hysterophorus in response to soil quality: implications for invasiveness   总被引：1，自引：0，他引：1  

C Annapurna  & J S Singh 《Weed Research》2003,43(3):190-198

Summary The performance of Parthenium hysterophorus , native to the tropical Americas and invasive to several countries, was evaluated for response to soil quality. Phenological (six stages) and quantitative growth variables [relative growth rates in height (R_h) and diameter (R_d)] were measured every fortnight. Based on harvest data, the variables, root:shoot (R:S) ratio, specific leaf area (SLA), relative growth rate in biomass (R_w), net assimilation rate (NAR) and dry matter allocation to plant components, were determined. High clay content in soils prolonged the rosette stage, enhanced R_h and R_d and hampered root growth, but promoted biomass allocation to shoots. The extreme degree of plant mortality was observed, with only 33.3% individuals surviving to reproduce in the soils with highest clay contents. This appears to be one of the most important findings that certainly has a major bearing on the range of adaptation of the weed. Seed mass declined whereas seed production increased in relatively coarser soils with the exception of nearly pure sand. In soils rich in clay, plants produced a smaller number of larger seeds. These data suggest that variation in fundamental functional traits would enable P. hysterophorus to adjust to a variety of habitat conditions.  相似文献   

Relationship between potato seed tuber contamination by Erwinia carotovora ssp. atroseptica, blackleg disease development and progeny tuber contamination     

I. K. Toth†  L. Sullivan  J. L. Brierley  A. O. Avrova  L. J. Hyman  M. Holeva  L. Broadfoot  M. C. M. Pérombelon  J. McNicol 《Plant pathology》2003,52(2):119-126

  相似文献   

Leaf, floret and seed infection of wheat by Pyrenophora semeniperda     

M. A. Campbell  R. W. Medd †‡ 《Plant pathology》2003,52(4):437-447

Infection processes of Pyrenophora semeniperda on seedling and adult wheat leaves and wheat ears were investigated. Almost 100% germination of conidia occurred on seedling leaves, compared with 20–30% on adult leaves. Appressoria formed over the anticlinal epidermal cell walls and haloes always accompanied infection. Sometimes papillae formed within the leaves as a resistance mechanism. Infection hyphae ramified through the intercellular spaces of the mesophyll resulting in cellular disruption. The infection processes on floral tissues were similar to those observed on leaves; however, no infection occurred on anther, stigmatic or stylar tissues. Infection of ovarian tissue occurred both with and without appressoria formation. Hyphae grew mainly in the epidermal layers and appeared unable to breach the integumental layer as no growth was observed in endosperm or embryo tissues. The optimum dew period temperature for conidial germination was 23·6°C, compared with 19·9°C for lesion development, 20·4°C for the production of infection structures on seedling leaves and 23·7°C for floret infection. Leaf disease development occurred in a logistic manner in response to dew period, with maximum infection observed after 21 h compared with > 48 h in seeds. An initial dark phase during the dew period was necessary for infection and temperature after the dew period had an effect, with significantly more numerous and larger lesions being formed at 15°C compared with 30°C. Seedling leaves were found to be more susceptible than older leaves, under both field and controlled environment conditions. Infection of wheat seeds following inoculation of ears, or after harvest burial of inoculated disease-free seeds, was demonstrated. In the latter, 3-week-old seedlings were slightly stunted, whereas older plants were unaffected. The apparent unimportance of this plant pathogen as a cause of leaf disease in relation to its poor adaptation to dew periods and dew period temperature is discussed, along with the importance of its seed borne characteristics.  相似文献   

两系稻制种穗期病害发生较重的原因及防治措施     

刘自君  蒲祖康 《中国植保导刊》2003,23(9):7-9

调查分析稻粒黑粉病、穗颈稻瘟等两系杂交稻制种穗期主要病害的发生原因,提出了清除菌源、轮换制种、健身栽培、对口药剂防治等防治措施。  相似文献   

一个马铃薯Y病毒山东分离物的分离与鉴定   总被引：4，自引：1，他引：4  

王秀芳  朱常香  温孚江  竺晓平  郭兴启 《植物病理学报》2003,33(3):203-208

 从具有典型花叶症状的马铃薯叶片中分离到马铃薯Y病毒(Potato virus Y,PVY)(本文称PVY-SD-TA分离物),扩繁后,提纯病毒,电镜下可观察到700~900 nm×11 nm的病毒粒体,病组织超薄切片观察可见风轮状的内含体结构,寄主反应特性研究表明其能侵染2科13种植物。SDS-PAGE电泳检测病毒编码的外壳蛋白亚基的分子量为33 kDa。以PVY-SD-TA基因组RNA为模板,应用RT-PCR方法和特异引物合成了外壳蛋白基因。对cDNA全序列分析表明,PVY-SD-TA CP基因核苷酸序列与N株系的同源性为96%,与GenBank中登录序列号为AJ390306的O株系分离物的同源性最高,为99%;与国内不同学者报道的PVY中国流行株的同源性分别为96%,97%和98%。通过以上生物学特性和分子水平的研究将PVY-SD-TA鉴定为普通株系(PVY^O株系)。  相似文献   

红汁乳菇多糖提取最佳工艺研究   总被引：10，自引：0，他引：10  

李志洲  杨海涛  邓百万 《中国食用菌》2003,22(5):40-42

对红汁乳菇多糖提取、纯化工艺进行了优化研究，结果表明在料液比1：30，浸提温度95％浸提时间2h,pH8．0，可获得最佳提取效果。在醇析浓度为70％，V(氯仿)：V(正丁醇)=1：0．2，V(氯仿 正丁醇)：V(样品)=1：l时，纯化含量为58％。同时用超声波法对红汁乳菇多糖的提取作了研究，其得率为6.99％，效果较佳。  相似文献   

A coat protein transgene from a Scottish isolate of potato mop-top virus mediates strong resistance against Scandinavian isolates which have similar coat protein genes     

Brian Reavy  Maria Sandgren  Hugh Barker  Pekka Heino  Per Oxelfelt 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(9):829-834

Resistance tests were made on seedlings of transformed lines of Nicotiana benthamiana which contain a transgene encoding the coat protein (CP) gene of a Scottish isolate of potato mop-top virus (PMTV). This transgene has been reported to confer strong resistance to the PMTV isolate from which the transgene sequence was derived and also to a second Scottish isolate. Plants of lines of the transgenic N. benthamiana were as resistant to two Swedish and two Danish PMTV isolates as to a Scottish isolate, and of five lines tested, greater than 93.5% of transgenic plants were immune. The coat protein gene sequences of these four Scandinavian isolates were very similar to those of the two Scottish isolates. The greatest divergence between the isolates was three amino acid changes and there was less than 2% change in CP gene nucleotide sequence. It is concluded that the PMTV CP transgene used in these experiments could confer resistance against isolates from different geographical areas because it is becoming apparent that the CP genes of PMTV isolates are highly conserved.  相似文献