α-茄碱对灰葡萄孢菌的体外抑菌活性研究

从马铃薯皮中提取分离出α-茄碱．通过牛津杯法研究α-茄碱对灰葡萄孢菌的体外抑菌活性,并采用平板涂布法测定其最低抑茵浓度（MIC）．结果表明,α-茄碱对灰葡萄孢菌具有较好的抑菌效果,且抑制强度呈剂量依赖性,当α-茄碱浓度为50μmol／L时．对灰葡萄孢菌表现出高度敏感性：α-茄碱对灰葡萄孢菌的最低抑菌浓度为15％。以灰葡萄孢菌为指示菌研究其稳定性．表明α-茄碱在中性（pH=7）条件下对灰葡萄孢菌的抑菌效力最强。当加热温度低于80℃时,α-茄碱的抑菌活性比较稳定,而当温度升高到121℃时．随着加热时间的增加．抑菌效果减弱。     

芥菜提取物对西瓜枯萎病菌的抑菌活性及抑菌谱测定

研究芥菜提取物的抑菌活性,为开发芥菜作为杀菌剂应用于农业生产奠定基础,为芥菜资源的合理利用提供理论依据。采用菌丝生长速率法,测定芥菜提取物对西瓜枯萎病菌、水稻纹枯病菌、葡萄座腔菌和烟草黑胫菌等植物病原菌菌丝生长的抑制作用。结果表明：采用不同有机溶剂获得的芥菜提取物对西瓜枯萎病均有一定抑制作用,以95%乙醇提取的抑菌效果最好,其提取物的抑菌率可达90%以上。最小抑菌浓度(MIC)和最小杀菌浓度(MFC)分别为0.5、1.0 g/mL,通过毒力方程的测定,它的半抑菌浓度(EC₅₀)为0.2212 g/mL。通过试验对其他10种植物病原菌的抑菌活性表明：芥菜乙醇提取物对水稻纹枯菌、葡萄座腔菌、烟草黑胫菌、辣椒菌核病菌等4种病原菌的抑菌效果较强,其EC₅₀分别为0.0898、0.1265、0.1679、0.1685 g/mL,对葡萄炭疽病菌的抑制效果最弱,EC₅₀为0.5833 g/mL。芥菜提取物具有很强的抑菌活性,并且具有较广的杀菌谱,值得进一步深入研究。     

5种瑞香科植提取物对7种植物病原真菌的抑菌活性测定

本研究旨在寻找出与瑞香狼毒同科的瑞香科植株是否有潜力成为防治病原真菌的植物资源,为筛选及制备有效且安全的植物源农药打开新思路。以5种试验材料作为瑞香科植物的代表,利用其乙醇提取物对番茄枯萎、黄瓜靶斑等7种病原真菌进行毒力测定。结果显示,瑞香狼毒与梦花在所有提取物中表现最佳,尤其是针对各种枯萎病病原菌,在较高浓度下的抑菌率都接近100%。而祖师麻提取物对黄瓜靶斑以及草莓红中柱的抑制效果在所有的提取物中表现最佳,其EC₅₀值分别为0.925、0.920 mg/mL。南岭荛花在5种瑞香科植物提取物中表现最差,但对番茄枯萎和黄瓜炭疽病原菌的抑制效果良好,EC₅₀值均小于1.1 mg/mL。研究表明,5种瑞香科植物提取物对病原真菌普遍有良好的抑菌活性,瑞香科植物可作为新型植物源农药的筛选靶标。     

芦荟对植物病原真菌生长的抑制效果

采用菌落生长速率法测定库拉索芦荟对18个属20个种的植物病原真菌的抑制效果，试验结果表明，库拉索芦荟对稻瘟病菌（Pyricularia oryzae）、芒果褐色蒂腐病菌（Phomopsis mangiferae）、苜蓿茎点霉（Phoma medicaginis）等17种真菌具有不同程度的抑菌活性。抑菌活性物质在叶皮及叶肉中均有分布，植物基部叶片的抑菌活性高于上部叶片。121℃1.5Mpa处理20min后芦荟汁的抑菌力显著下降。     

土木香对植物病原菌抑菌活性的初步研究

以黄瓜白粉菌、黄瓜霜霉菌、黄瓜炭疽菌、番茄灰霉菌、番茄叶霉菌为供试菌,测试了土木香甲醇、乙醇提取物以及乙醇提取物不同萃取组分的抑菌活性。结果表明:土木香的不同溶剂提取物对5种供试菌都有一定程度的抑制作用,乙醇提取物比甲醇提取物抑菌活性高。土木香乙醇提取物在浓度为0.005 g/mL时,对黄瓜白粉菌、黄瓜霜霉菌的抑制率分别达到99.95%,96.30%。在乙醇提取物不同的萃取组分中,石油醚部分的抑菌活性最强。     

苦楝果实提取物对Bt-8010和Bt-7216的抑菌活性

将采摘的苦楝果实烘干、粉碎,以甲醇为溶剂,用超声波法提取苦楝果实的提取物,配成不同浓度的苦楝果实提取液,用于测定2种生物农药Bt_8010和Bt_7216的抑菌圈和抑菌率。结果表明:苦楝果实提取液浓度越高,其抑菌程度越大。其中,对Bt_7216的抑菌活性较大,Bt_8010次之。高浓度的苦楝提取物与生物农药(Bt)混用会降低Bt的药效。     

草珊瑚乙醇提取物的抗氧化性及其对芒果采后主要病原菌的抑菌活性研究

以无水乙醇为溶剂制备草珊瑚全草提取物,测定其总酚和总黄酮含量,提取物对DPPH自由基与ABTS自由基的清除能力,以及不同浓度草珊瑚乙醇提取物对芒果采后常见3种病原菌的抑菌活性及对病原菌孢子萌发的影响。结果表明：草珊瑚乙醇提取物中的总酚含量为7.62%,总黄酮含量为6.13%;对DPPH自由基和ABTS自由基均有一定的清除能力,在低浓度（0.001 mg/mL）范围内对DPPH自由基的清除能力可超过BHT。草珊瑚乙醇提取物对3种芒果采后病原菌均有一定的抑菌效果,其中对拟茎点霉蒂腐菌的抑制效果最佳,2.5 mg/mL提取物处理即可有效抑菌,处理7 d时抑制率达到50.29%;对胶孢炭疽菌的抑制效果次之,5 mg/mL提取物处理7 d时抑制率为41.25%;对可可球二孢蒂腐菌的抑制效果相对较弱,5 mg/mL提取物处理6 d抑制率仅10.67%。     

茶叶活性成分对梨火疫病菌的抑制活性及稳定性研究

研究茶叶活性成分对梨火疫病菌的抑菌活性及其稳定性,旨在为田间病害防治提供依据。采用打孔法测定茶叶活性成分对梨火疫病菌的抑菌活性及最小抑菌浓度(MIC),并进一步探讨温度、pH和紫外线照射对绿茶提取物茶多酚抑菌活性稳定性的影响。结果表明,抑菌活性绿茶提取物茶多酚>壳寡糖,茶皂素没有抑菌活性;绿茶提取物茶多酚MIC为40 mg/mL。绿茶提取物茶多酚10～60℃时抑菌活性保持稳定,但经高温80～100℃处理后,抑菌活性略有下降;在p H 2时抑菌活性增强,碱性条件下抑菌活性减弱;经紫外处理10～50 min后,抑菌活性随着照射时间的增加而减弱。茶叶活性物质对梨火疫病菌有一定的抑菌活性,且绿茶提取物茶多酚具有较稳定的抑菌活性,为其作为天然的农药防治梨火疫病提供依据。     

吴茱萸不同溶剂提取物抗氧化和抑菌性研究

【摘要】 采用清除DPPH·和·OH法评价吴茱芡不同溶剂水、甲醇、乙醇和乙酸乙醋提取物的抗氧化活性。同时,通过测定抑菌圈直径大小研究吴茱萸不同溶剂提取物对金黄色葡萄球菌、枯草芽抱杆菌和大肠杆菌的抑菌效果。结果表明:吴茱萸不同溶剂提取物均具有较强的抗氧化活性和抑菌活性,且以吴茱萸的乙醇提取物抗氧化和抑菌活性最强。溶剂对吴茱萸提取物抗氧化和抑菌活性有明显影响,说明选择合适溶剂有助于吴茱萸抗氧化和抑菌活性成分的溶出。     

中药抑制番茄晚疫病原菌的配伍筛选及抑菌效果初步研究

为得到对番茄晚疫病原菌有更好抑制作用的生物药剂,对15种中药进行筛选,并进行配伍抑菌研究,得出最佳三配伍抑菌组合为青蒿∶五味子∶乌梅=1∶4∶1,抑菌圈直径达到了56 mm,最佳配伍液的最小抑菌浓度(MIC)为7.82 mg/mL,最小杀菌浓度(MBC)为31.25 mg/mL,对生长曲线的抑制作用明显。将该中药配伍液稀释500～1 000倍时,其抑菌率明显高于典型化学抑菌剂。     

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.