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。     

冬枣采后浆胞病定性研究

对冬枣采后贮藏期间危害最为严重的病害--浆胞病进行了定性研究,通过对其病原菌的分离、培养和回接试验,确定了冬枣浆胞病为混合感染,病原菌种类分别为交链孢霉菌和根菌索菌两种;同时调查不同温度对冬枣浆胞病病原菌生长的影响.     

山东省玉米穗腐病病原菌的分离鉴定及优势种的系统发育分析

旨在明确山东省玉米穗腐病病原菌组成及优势病原菌的流行趋势。对2015-2017年在山东省采集的138份玉米穗腐病样品进行了病原菌的分离,采用形态学和分子生物学方法对分离物进行鉴定,并对优势病原菌进行系统发育分析,明确其发生发展规律。分离鉴定结果表明,分离到的真菌共有18种,其中镰孢属的拟轮枝镰孢菌分离频率为67.39%,为山东省优势病原菌;其次为层出镰孢菌,分离频率为10.87%;禾谷镰孢复合种、木贼镰孢菌和尖孢镰孢菌的分离频率分别为7.97%,5.80%,0.72%;木霉属的哈茨木霉分离频率为7.91%;青霉属的草酸青霉分离频率为6.52%;曲霉属黄曲霉和黑曲霉的分离频率分别为2.17%和5.07%。基于EF-1α基因序列构建了山东省2015-2017年拟轮枝镰孢菌的系统发育树,并分析了山东省菌株与河北省菌株的遗传进化关系。系统发育分析结果发现,89个拟轮枝镰孢菌菌株可以分为2个大群,其遗传距离较小,为0.002～0.016,表明山东省2015-2017年的菌株之间遗传关系较近;河北省和山东省拟轮枝镰孢菌菌株的遗传距离较小,相似性较高,亲缘关系较近,存在较为频繁的基因交流。研究结果为深入开展拟轮枝镰孢菌穗腐病的抗性育种、发生发展规律以及综合防治提供科学依据。     

生防酵母菌结合钼酸铵对冬枣采后主要病害防治的研究

研究美极梅奇酵母菌(Metschnikowia pulcherrima)与不同浓度(5、10、15、20 mmol/L)的钼酸铵结合使用对冬枣果实采后黑腐病和青腐病的防治效果以及钼酸铵对美极梅奇酵母菌生长的影响。结果表明,不同浓度的钼酸铵对美极梅奇酵母菌的生防效果影响不同,其中美极梅奇酵母菌与较低浓度(5 mmol/L)的钼酸铵溶液结合使用时对冬枣果实黑腐病和青腐病的防治效果最佳,美极梅奇酵母菌在含有5 mmol钼酸铵的NYDB液体和固体培养基以及冬枣伤口上的生长都未受到明显的抑制。因此,美极梅奇酵母菌与钼酸铵结合使用在控制冬枣采后贮藏中的病害方面具有潜在的应用价值。     

冬枣贮藏保鲜现状与对策

1目前冬枣贮藏保鲜的主要问题1.1腐烂冬枣皮薄质脆,营养丰富,易受微生物侵染而导致腐烂。通过几年的探索和实践发现,冬枣在贮藏期间极易发生腐烂现象可分为两种情况:一种是由于机械伤引起的外部腐烂,主要发生在表皮、梗洼等伤口部位,在正常贮藏条件下发病时间是在贮藏之后的2个月左右,这种由机械伤感染引起的腐烂可通过在采收运输过程中减少出现伤口来控制,也可通过采后表面消毒措施来解决;另一种情况是由病原菌潜伏侵染而造成。病原菌在田间侵染果实(主要侵染期为花期和幼果期),之后一直潜伏在果实内,潜伏侵染的病原菌隐藏在冬枣果肉组织中…     

云南省烟草青枯病危害调查与病原菌分离

为了了解云南省烟草青枯病的危害情况,指导病害预测预报与综合防治;2004年至2006年,对云南省烟草青枯病的发生进行了调查,对田间采集的烟草茎下部黑色坏死症状样品进行了病原菌分离。在文山州文山县、砚山县、广南县、西畴县和麻栗坡县主要栽烟乡镇的重病田块,茎下部黑色坏死病株86.3%感染青枯病,27.7%感染黑胫病,其中包括14%病株复合感染青枯病和黑胫病。从云南省12个县(市)采集的258个烟草病样中分离青枯雷尔氏菌株219个,病原菌回接试验和ELISA检测结果表明文山州、保山市的烟草茎下部黑色坏死症状病害,大部分为烟草青枯病,伴随部分黑胫病。     

冬枣贮藏期浆胞病病原分离与鉴定

在天津地区栽培的冬枣上发现冬枣贮藏期浆胞病真菌病害,从病果上分离出2种真菌菌株,回接后,发现病症与自然发病症状完全一致,而且从接种病果上又重新分离到了此病病原真菌,经鉴定和致病性测定,确认为链格孢菌(Alternaria alternata(Fr.)Keissl)和裸孢壳属(Emericella nidulans(Eid.)),其中裸孢壳属(Emericella nidulans(Eid.))在冬枣上还属国内外首次报道.     

甘薯茎腐病已侵入河北

<正>甘薯茎腐病又名甘薯黑腐病,目前该病已在我国的福建、广东、江西、广西、海南、河南、重庆、江苏等地发生。2013年10月,河北省农林科学院植物保护研究所在对河北省甘薯病害的调查中,在文安县发现了大量疑似甘薯茎腐病的病株,给当地的甘薯生产造成了严重的影响。经对疑似病株病原菌的分离纯化、柯赫氏法     

褪黑素诱导采后冬枣抗黑斑病的研究

分别用0、2、20、200μmol/L褪黑素处理接种链格孢菌(Altrenaria alternata)的采后冬枣,研究褪黑素对冬枣采后黑斑病的抗病作用.结果显示:褪黑素处理可以抑制病斑直径的扩展,降低冬枣的腐烂指数和失重率,抑制冬枣呼吸速率和相对电导率的上升,使丙二醛(MDA)含量保持在较低水平;此外,褪黑素处理还提高了苯丙氨酸解氨酶(PAL)、几丁质酶(CHI)、β-1,3-葡聚糖酶(GLU)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性以及抗病相关物质(黄酮、总酚、木质素)的含量.上述结果表明,褪黑素可以通过激活抗病相关酶活性和提高抗真菌物质含量来提升冬枣采后抗黑斑病的能力,可作为一种有潜力的激发子,提高果实对采后病原菌的抗性,从而用于采后果实的腐烂防治.     

拮抗酵母菌结合热水浸泡处理对冬枣采后腐烂及品质的影响

采用拮抗酵母菌（美极梅奇酵母菌（Metschnikowia pulcherrima））单独处理或结合热水浸泡处理（55 ℃,30 s）冬枣果实, 研究在模拟货架条件下（24 ℃）贮藏7 d,不同处理对人工接种橘青霉或链格孢菌后冬枣伤口的腐烂率、病斑直径和对冬枣自然腐烂及贮藏品质的影响。结果表明,采用拮抗酵母菌单独处理及结合热水浸泡处理都可显著降低人工接种致病菌冬枣的腐烂率、病斑直径及减轻冬枣的自然腐烂程度,并能提高冬枣的贮藏品质,其中以美极梅奇酵母菌结合热水浸泡处理的效果最佳,是一种可替代化学杀菌剂控制冬枣果实采后腐烂的较理想的处理方法。     

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.     

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.     

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...     

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.     

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.