冬枣黑点病病原鉴定

冬枣黑点病主要为害冬枣果实,在果面上产生黑斑,影响果实的外观及品质。2004~2005年连续2年对河北省黄骅市的不同枣区采集的病果进行分离接种及再分离,结果证实冬枣黑点病病原为:桑壳小圆孢菌(ConiothyriumfucsidulumSacc)、仁果茎点霉(Phoma pomirumThüm)以及细极链格孢(Alternaria alternata(Fr.)Keissler),其中(Conio-thyrium fucsidulumSacc)和(Phoma pomirumThüm)既可单独侵染,也可混合侵染,(Alternaria alternata)只参与混合侵染。     

芦荟黑斑病发生规律及室内药剂筛选

为了解芦荟黑斑病的发生规律,进一步为防治提供理论依据。该文对三种越冬形式的病原菌分别采用直接镜检、组织分离法及致病性测定对芦荟黑斑病菌（Alternaria obpyriformis T. Y. Zhang）进行了越冬场所和越冬方式的研究。通过针刺法、涂抹法及玻片粘着法确定病菌侵入和传播途径。人工接种条件下测定了病菌对5科10种植物的侵染能力。采用孢子萌发法和菌丝生长速率法对病菌进行室内药剂筛选。结果表明,病原菌可在病残体上以菌丝和分生孢子越冬,通过气孔和伤口侵入寄主,分生孢子能借助气流传播;人工接种时能侵染豆科、十字花科的部分植物。供试的7种药剂对病菌菌丝生长和孢子萌发都有显著的抑制作用,其中施保功可湿性粉剂对其病菌的菌丝体抑制效果最好,抑菌率达84.24%;扑海因悬浮剂对分生孢子萌发抑制效果最佳,抑制率为67.44%。     

黑龙江省马铃薯叶斑类病害Alternaria属病原组成和分布

生产上常见的马铃薯叶斑类病害主要包括马铃薯早疫病、黑点病和黑斑病等,均导致马铃薯植株叶片枯死、严重时侵染块茎,造成减产。马铃薯早疫病、黑点病和黑斑病的病原分别为茄链格孢菌(Alternaria solani)、链格孢菌(Alternaria alternata)和细极链格孢菌(Alternaria tenuissima),是Alternaria属的三个不同种。本研究旨在针对Alternaria属这三个病原建立一套PCR快速分子鉴定技术,同时结合传统生物学鉴定方法,调查分析黑龙江省马铃薯叶斑类病害Alternaria属病原的小种组成和发生分布情况。结果表明:利用通用引物H3-1a/H3-1b对感染Alternaria病原菌的马铃薯植株病样进行PCR扩增,在489 bp、440 bp和546 bp处出现条带,经测序比对分析,三处目的条带分别鉴定为茄链格孢菌(Alternaria solani)、链格孢菌(Alternaria alternata)和细极链格孢菌(Alternaria tenuissima)。对2015年采集自黑龙江省马铃薯主产区的55个植株叶斑类病样进行生物学和PCR鉴定,结果显示大部分病样为Alternaria属多个小种混合侵染,主要是A.tenuissima、A.alternata和A.solani,这三种病原所占被测病样总数百分比分别为71%、45%和33%,A.tenuissima为优势小种。本研究结果将为准确检测马铃薯植株叶斑类病原菌提供技术支持,为生产上有的放矢防控马铃薯叶斑类病害提供帮助。     

杏贮藏过程中主要致病菌的分离与鉴定

为有效控制杏果采后贮藏中的主要致病菌,对贮藏中腐烂小白杏果实上的病菌进行了分离与鉴定。分离并筛选得到了3种主要霉菌,经过形态结构鉴定和显微镜观察,确定为粉红单端孢霉（Trichothecium roseum）、链格孢霉（Alternaria alternata）和天门冬拟茎点霉（Phomopsis asparagi）。经过回接发现,该3种霉菌能使健康杏果致病,且病状与自然发病一致,从这些病斑中又分离得到了相同的霉菌,从而确定该3种霉菌为小白杏采后的主要致病菌。     

大樱桃黑斑病病原菌及其致病性基本明确

<正>沈阳农业大学植物保护学院近期通过研究,基本明确了大樱桃黑斑病病原菌及其致病性。研究人员通过形态学鉴定和rDNA-ITS序列分析,确定大樱桃黑斑病病原菌为链格孢(Alternaria alternata)。致病性测定结果表明:该菌可以直接侵染或通过自然孔口和伤口侵染大樱桃果实,伤口接种的果实发病较重;该菌对有伤叶片具有一定的致病能力,不侵染无伤叶片;该菌对梨、杏、李等果实致病性较强,对山楂果实的致病能力相对较弱。     

水杨酸诱导鸭梨抗黑斑病效果及机理的探讨

为了揭示水杨酸诱导鸭梨抗黑斑病的作用效果及机理，以河北农业大学实验农场梨园鸭梨叶片和果实为试验材料，通过组织分离法分离、纯化梨黑斑病病原菌并对其进行致病性检测，利用形态观察及真菌ITS、HIS、RPB2、ACT多基因综合鉴定法明确鸭梨黑斑病致病菌的类型；鸭梨离体叶片通过针刺接种黑斑病菌分生孢子悬浮液侵染0,6,12,24,48,72,96,120 h,通过实时荧光定量PCR检测水杨酸信号通路中相关基因的表达量变化，通过高效液相色谱(HPLC)检测0,72 h内源水杨酸含量的变化；利用不同浓度水杨酸(0,0.002,0.02,0.2,2.0,10.0,20.0 mmol/L)测定其对黑斑病菌菌丝生长的影响；采用外源0,0.02,0.2,2.0 mmol/L水杨酸处理鸭梨果实，接种黑斑病菌并观察其抗病效果。结果表明，河北农业大学实验农场梨园中鸭梨黑斑病病原菌为链格孢属链格孢菌，鸭梨离体叶片接种黑斑病菌后，72 h游离态水杨酸含量由0 mg/g增至0.02 mg/g,结合态水杨酸含量由0.47 mg/g增至1.55 mg/g, SA信号通路中相关基因Pbrgene12425、Pbrgene6...     

科学防治“梨黑屁股病”

<正>梨黑屁股病是随着套袋梨的发展逐步严重起来的一种新病害,果农称之为梨黑屁股病,主要指的是在梨花萼处出现黑点或者黑斑,一旦发病任何药剂都无法消除黑色病斑,使大量梨果失去商品价值,给果农造成严重损失。特别是黄冠梨、绿宝石在果实生长后期遇到降雨多、     

葡萄贮藏保鲜期间常见病害与防治技术

葡萄在贮藏保鲜过程中常见的主要病害有葡萄灰霉病、霜霉病、葡萄脱粒、SO2伤害等. (1)葡萄灰霉病 灰霉病菌在-5℃仍可生长,属于葡萄低温保鲜的主要病害之一,也是鲜食葡萄中具有毁灭性的病害,多数品种对该病菌无抵抗力.灰霉菌侵染果皮后,形成灰色分生孢子梗,孢子菌丝体呈白色,果实腐烂后为水浸状斑,变褐色,在潮湿条件下加快蔓延到葡萄果粒全部染病为止.     

果桑肥大性菌核病菌和油菜菌核病菌的交叉侵染、生物学特性及遗传关系

分别以果桑肥大性菌核病菌和油菜菌核病菌的子囊孢子交叉接种油菜和果桑。结果表明,杯盘菌子囊孢子能够侵染油菜,同样,核盘菌子囊孢子能够侵染果桑;在受侵染的桑椹上2种病菌均产生分生孢子梗和分生孢子,而在油菜上不产生。显微镜观察,杯盘菌的子囊盘外囊被切面为圆胞组织结构,核盘菌为角胞组织结构。SRAP分子标记和聚类结果表明,采自西南地区果桑上的杯盘菌和油菜上核盘菌基本各自聚在一类,其中一个杯盘菌分离物和一个核盘菌分离物聚在一类,表现特别。2种寄主上的病菌子囊孢子能相互侵染,因而果桑和油菜不能间套种植。     

玉米灰斑病菌致病过程的寄主反应研究

通过对玉米灰斑病菌侵染后的显症过程的系统观察,可在组织水平上说明该病菌与寄主互作反应存在分化或多样性：玉米灰斑病菌不同菌株侵染后显症过程表现出明显的差异;玉米灰斑病菌在侵袭力上存在多样性,菌株间对同一种品种的致病性表现多样化,或者同一菌株对不同品种侵染引起的寄主反应表现为多样性;病斑反应型的分化,玉米灰斑病菌侵染玉米品种或自交系后,主要有7种病斑反应类型,即RH型(长矩形具褪绿晕圈病斑)、RN型(长矩形无褪绿晕圈病斑)、IRH型(不规则形具褪绿晕圈病斑)、IRN型(不规则形无褪绿晕圈病斑)、SH型(斑点形具褪绿晕圈病斑)、RI型(长矩形与不规则形混合病斑)和RS型(长矩形与斑点形混合病斑),若发病严重,病斑连成片,而且这些反应类型出现的频率也不同。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.