牡丹叶及其不同溶剂提取物对生菜等幼苗生长的抑制效应

为了进一步明确牡丹叶及其不同溶剂提取物的化感活性大小,于室内采用琼脂混粉法测定了牡丹叶粉末在不同浓度下对生菜、小麦、黄瓜、稗、夏至草、播娘蒿和独行菜等7种受体植物幼苗生长的影响.结果表明,虽然在低浓度下牡丹叶粉末对各受体植物幼苗生长的影响差异较大,但在高浓度时均表现出了较高的抑制作用,且对胚根(或种子根)的抑制效果明显高于对胚轴或胚芽鞘的抑制.计算对各受体植物胚根或种子根、胚轴或胚芽鞘的有效中浓度(EC50),生菜为0.93～5.25 g/L、小麦为1.20 ～4.65 g/L)、黄瓜为3.58～＞10.0 g/L、稗为0.64～3.36 g/L、夏至草为1.09～5.27 g/L、播娘蒿为1.02 ～9.65 g/L、独行菜为0.79 ～6.84 g/L,以稗的敏感性最高,黄瓜最低.继而探索了牡丹叶乙醇、甲醇和蒸馏水3种溶剂提取物对生菜幼苗生长的抑制效果,发现乙醇提取物的活性最高,提取浓度以80％ (V/V)为宜.     

中华真地鳖抗菌物质的抑菌活性测定

以研磨法从中华真地鳖五龄若虫体内提取得到抗菌物质,分别采用比浊法和菌碟法测定了其对多种细菌和植物病原真菌的抑菌活性。结果表明,该抗菌物质对大肠杆菌、金黄色葡萄球菌、白菜软腐菌和枯草芽孢杆菌等4种细菌生长均有一定的抑制作用,对数期延迟1~4h,菌的浓度、繁殖速度减缓。对7种植物病原真菌的抑菌试验表明,该抗菌物质对玉米茎基腐病菌、小麦根腐病菌、棉花枯萎病菌抑制效果较好,抑制率分别为50.0%、49.2%、45.2%;而对白菜黑斑病菌和玉米大斑病菌活性较差,抑制率仅为28.3%和24.5%。     

牡丹不同器官的除草活性研究

［目的］ 明确牡丹不同器官的除草活性,为进一步开展活性化合物的研究提供依据。［方法］ 以生菜、黄瓜、反枝苋、苘麻、小麦和稗为受试植物,采用琼脂混粉法进行室内活性测定。［结果］ 除茎器官外,牡丹其他各器官的粉末在10 g/L的添加浓度下,对各受体植物幼苗的生长均具有明显的抑制作用,且对胚根（或种子根）的抑制效果明显高于对胚轴（或胚芽鞘）的抑制。各器官中以根和叶的效果最好,花、果实和叶柄次之,茎最低。6种受体植物中,反枝苋幼苗的敏感性最高,而黄瓜最低。［结论］ 牡丹的不同器官粉末在10 g/L的添加浓度下对各受体植物幼苗的生长均具有不同程度的抑制作用。     

20种植物花粉对真桑钝绥螨饲养效果的综合评判

通过对20种植物的花粉筛选,证明有14种花粉可使真桑钝绥螨完成发育,有10种可令该螨继代繁殖。采用模糊综合评判法,以花粉参数和繁殖效果等共10项指标作为参评因素,确认黄瓜、茉莉花和马缨丹的花粉适于室内饲养作饲料用。     

Allelopathic effects of Hemistepta lyrata on the germination and growth of wheat, sorghum, cucumber, rape, and radish seeds

The allelopathic effects of a water extract from Hemistepta lyrata were tested on the seeds of selected crops in Petri dishes. The results showed that the extract strongly inhibited the germination and seedling growth of wheat ( Triticum aestivum ), rape ( Brassica campestris ), and radish ( Raphanus sativus ), but only slightly inhibited those of sorghum ( Sorghum vulgare ) and cucumber ( Cucumis sativus ). The extract stimulated the growth of roots and hypocotyls at lower concentrations, while it inhibited their growth at higher concentrations. The malondialdehyde (MDA) content of cucumber and radish increased after treatment with the extract. These results indicated that the MDA concentration in plants is one important aspect of the allelopathic effects of H. lyrata .     

Plant-growth-regulating N-(phosphonoacetyl)amines

A series of N-(phosphonacetyl)amine derivatives were synthesized and screened for plant-growth regulating activity on Lepidium sativum L. and Cucumis sativus L. Aromatic N-(phosphonoacetyl)amines. which may be considered as possible analogues of N-acylaniline herbicides obtained by replacement of their acyl group by the phosphonacetyl moiety, exhibited significant or moderate herbicidal activity. In contrast, N-(phosphonoacetyl)amino acids and N-(phosphonoacetyl)aminophosphonic acids promoted the growth of L. sativum and C. sativus roots.     

乌桕不同器官除草活性研究

在10 g/L的浓度下,乌桕不同器官粉末对生菜和小麦幼苗的生长均有较高的抑制活性,且以叶器官活性最高,果实最低。而叶在0.1～10.0 g/L的不同浓度下对夏至草、反枝苋、生菜、荠菜、小麦和黄瓜幼苗的生长具有不同程度的抑制作用,且抑制活性随浓度的增加而提高,其中以夏至草的敏感性最高,而黄瓜最低。     

绒叶泡桐花中除草活性成分的分离与除草活性

采用活性追踪和柱层析技术,以对杂草反枝苋、生菜、黄瓜种子胚根生长的抑制作用为指标,对泡桐花中除草活性成分进行了提取、分离和鉴定。绒叶泡桐Paulownia tomentosa花乙醇提取物依次用石油醚、乙酸乙酯、正丁醇和水萃取后进行活性测定,结果表明,石油醚萃取物在浓度为 0.5 mg/mL 时,对反枝苋、生菜和黄瓜种子胚根生长的抑制率分别为76.30%、56.17%和23.36%; 乙酸乙酯萃取物在浓度为0.5 mg/mL时,对反枝苋、生菜和黄瓜种子胚根生长的抑制率分别为99.89%、63.53%和32.74%。通过对乙酸乙酯萃取物进行硅胶柱层析分离,得到一种活性较高的化合物,经鉴定其为对乙氧基苯甲醛,其抑制反枝苋种子胚根生长的EC50值为55.20 μg/mL。对乙氧基苯甲醛是首次从绒叶泡桐中分离鉴定的化合物,也是首次将其用于除草活性研究。     

Plant-growth-regulating phosphono peptides

Phosphono peptides exhibited plant-growth-regulating activity when tested on Lepidium sativum and Cucumis sativus. The studies have provided evidence that the mechanism of action of these compounds may involve the uptake of the phosphono peptides into the plant, intracellular hydrolysis of the peptide bond and release of the P-terminal aminoalkylphosphonic acid. This acid or its metabolite is then probably responsible for the observed physiological effect.     

Herbicidal and fungicidal activities and identification of potential phytotoxins from Bidens pilosa L. var. radiata Scherff

This study was carried out to examine the possibility of utilizing Bidens pilosa , a weed widely distributed in the subtropics and the tropics, for weed and plant fungus control. The extract of B. pilosa shows strong phytotoxic action against the growth of Raphanus sativus and Echinochloa crus-galli and antifungal activity against phytopathogens in bioassays. The extract of the roots exhibited plant growth inhibitory activity more than those of the leaves and stems. Fifteen phenolic compounds, including pyrocatechin, salicylic acid, p -vinylguaiacol, dimethoxyphenol, eugenol, 4-ethyl-1,2-benzenediol, iso- vanillin, 2-hydroxy-6-methylbenzaldehyde, vanillin, vanillic acid, p -hydroxybenzoic acid, protocatechuic acid, p -coumaric acid, ferulic acid, and caffeic acid were identified by gas chromatography–mass spectrometry. Caffeic acid was in the highest amount among the detected substances. Dimethoxyphenol and vanillic acid were found only in the roots of B. pilosa . Ferulic acid and p -hydroxybenzoic acid were higher in the roots than in the leaves and stems. These identified constituents might be responsible for the phytotoxic and fungitoxic activities of B. pilosa.     

Assessment of Host-Induced Selection on Three Geographic Isolates of Heterodera schachtii Using RAPD and AFLP Markers

ABSTRACT The hypothesis that host plants exert selection pressure on Heterodera schachtii populations was tested. Host selection of genotypes from three genetically distinct isolates of H. schachtii was assessed using cabbage, sugar beet, oilseed radish (Raphanus sativus), and white mustard (Sinapis alba). The plants represent a range of susceptibility to H. schachtii and included R. sativus and S. alba, because cultivars of those species have been used as trap crops for H. schachtii in Europe. Genotypic differences in amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) markers were detected among the isolates after they reproduced on the different hosts. The poorest host plant, R. sativus, resulted in the greatest number of changes in both AFLP and RAPD markers. Oilseed radish selected nematode genotypes in less than four nematode generations. The nematode population genotypes detected by RAPD analyses after selection on oilseed radish were observed even after nematode populations were transferred back to the other three hosts. The genetic markers that were detected after selection were influenced by the genotypes of the original nematode isolates. The results indicate the utility of RAPDs and AFLPs for identifying and monitoring intraspecific genetic variability in nematodes and for understanding nematode population responses to host plants. Nematode management practices such as using resistant cultivars may alter gene frequencies, thereby reducing the efficacy of the tactic and exacerbating the nematode's potential to damage subsequent crops.     

剑麻叶不同溶剂浸提液对假臭草萌发和生长的影响

以剑麻园常见伴生杂草假臭草为受体植物,白菜和萝卜为参照受体植物,采用生物测定的方法研究剑麻新鲜叶片石油醚、乙酸乙酯、三氯甲烷、蒸馏水4种溶剂浸提液对受体植物种子萌发和生长的影响。结果表明,4种溶剂浸提液对受体植物种子萌发率、根长和茎长生长均有不同程度的影响。500mg／mL蒸馏水浸提液和三氯甲烷浸提液对假臭草种子的萌发和幼苗的根长总体上具有显著的抑制作用,抑制率分别达到29％和50％;500mg／mL蒸馏水浸提液对萝卜种子萌发和根长生长具有显著的抑制作用,抑制率分别达到45．00％和64．22％;500mg／mL乙酸乙酯浸提液对白菜种子萌发和根长生长的抑制作用较强,抑制率分别达到30．49％和56．59％。说明剑麻不同溶剂、不同浓度浸提液对不同的受体植物均存在不同程度的化感作用,这为进一步开展利用剑麻的化感物质抑制杂草的研究提供了理论基础。     

荆条不同器官除草活性研究

为了明确荆条不同器官的除草活性,为进一步开展活性化合物的研究提供依据,采用琼脂混粉法于室内测定荆条对生菜、黄瓜、反枝苋、苘麻、小麦和稗草6种受体植物的除草活性。结果表明,在10 mg/mL的供试浓度下荆条不同器官粉末对6种植物幼苗均有明显的抑制作用,其中以花活性最高。进一步测定了花乙醇提取物及不同溶剂极性萃取物对6种植物幼苗生长的抑制作用,石油醚层和乙酸乙酯层的抑制活性较高,其中石油醚层对黄瓜幼根和乙酸乙酯层对稗草幼根的EC50分别为0.07、0.03 mg/mL,说明花含有较高的除草活性物质。     

Molecular mapping of Loci conferring resistance to different pathotypes of the spot blotch pathogen in barley

ABSTRACT Spot blotch, caused by Cochliobolus sativus, is an important disease of barley in many production areas and is best controlled through the deployment of resistant cultivars. Information on the genetics of resistance in various sources can be useful in developing effective breeding strategies. Parents of the doubled haploid mapping population Calicuchima-sib/ Bowman-BC (C/B) exhibit a differential reaction to pathotypes 1 and 2 of C. sativus. To elucidate the genetics of spot blotch resistance in this population, C/B progeny were evaluated with both pathotypes at the seedling stage in the greenhouse and at the adult plant stage in the field. At the seedling stage, progeny segregated 84 resistant to 26 susceptible based on the qualitative analysis of infection response (IR) data to pathotype 1. This fit best to a 3:1 ratio, indicating that two genes were involved in conferring resistance. Quantitative analysis of the raw IR data to pathotype 1 revealed a single quantitative trait locus (QTL) on chromosome 4(4H) explaining 14% of the phenotypic variance. Adult plant resistance to pathotype 1 was conferred by QTL on chromosome 2(2H) and chromosome 3(3H), explaining 21 and 32% of the phenotypic variation, respectively. Bowman contributed the resistance alleles on chromosome 3(3H) and chromosome 4(4H), whereas Calicuchima-sib contributed the resistance allele on chromosome 2(2H). Resistance to pathotype 2 was conferred by a single gene (designated Rcs6) on chromosome 5(1H) based on qualitative analysis of data. Rcs6 was effective at both the seedling and adult plant stages and was contributed by Calicuchima-sib. This result was corroborated in the quantitative analysis of raw IR (seedling stage) and disease severity (adult plant stage) data as a single major effect (r(2) = 0.93 and 0.88, respectively) QTL was identified on chromosome 5(1H). Progeny with resistance to both pathotypes were identified in the C/B population and may be useful in programs breeding for spot blotch resistance.     

啤酒花矮化类病毒及其突变体侵染性克隆的构建和生物学活性研究

  啤酒花矮化类病毒重组突变体（HSVd D 15）是世界上报道过的仅有的一个啤酒花矮化类病毒（HSVd）分子内重组突变体。为研究其生物学活性,本文分别构建了含有HSVd和HSVd D 15 cDNA加倍串联序列的重组质粒,并对其在指示植株四叶黄瓜上的侵染活性进行了检测。结果表明：仅在接种含有HSVd cDNA多倍串联序列重组质粒的黄瓜上检测到HSVd的侵染,在同样条件下接种了含有HSVd D 15 cDNA两倍串联序列重组质粒的黄瓜上未检测到子代类病毒。HSVd D 15的生物学活性还需通过改进接种方法或将其接种无毒的自然寄主李树苗木来进一步研究。     

Epidemiology of foliar blights (spot blotch and tan spot) of wheat in the plains bordering the himalayas

ABSTRACT Helminthosporium leaf blight (HLB), a complex of spot blotch caused by Cochliobolus sativus and of tan spot caused by Pyrenophora tritici-repentis, is a major wheat disease in South Asia. This 2-year study elucidated HLB development and its impact on yield. Symptoms caused by C. sativus and P. tritici-repentis were first observed at the seedling and tillering stages, respectively. The number of airborne conidia and leaves infected by the two pathogens remained low for several weeks under lower temperatures, followed by a sharp rise as temperatures increased. The number of airborne conidia of C. sativus and incidence of infection by C. sativus were higher compared with P. tritici-repentis. The disease complex caused an average 30% reduction in yield, with greater losses under delayed seeding. Delayed seeding increased disease severity even in resistant genotypes and caused higher yield losses. 'Milan/Shanghai-7' was the most resistant among six genotypes evaluated. Despite higher disease severity, 'BL 1473' showed relatively lower yield losses, indicating its tolerance to foliar blight. The findings of this study bear implications for integrated foliar blight management in the warmer areas of South Asia by combining optimum seeding date, seed treatment and foliar spray of fungicides, and resistant wheat genotypes.     

Quelques aspects de la physiologie des radis (Raphanus sativus L.) traités par la simazine

Some aspects of the physiology of radishes (Raphanus sativus L.) treated with simazine. III.The evalution of nitrogen The effect of simazine on the overall metabolism of nitrogen and on protein synthesis in radish (Raphanus sativus L.) was studied. In Ihe roots and petioles the total nitrogen content showed litlle change, whereas it showed a marked increase in the leaf blades about the 5th and 6th days after treatment; it subsequently decreased but remained higher than the initial quantity; then it became stable until the plant died. Radishes treated with simazine absorbed more nitrogen than the control. Study of protein nitrogen, organic soluble nitrogen and nitrate nitrogen showed that simazine did not affect protein synthesis.     

侵染番红花的芜菁花叶病毒

 从表现花叶症状的德国进口番红花上获得一线状病毒分离物SA,线状病毒粒子长度为700~800nm。其在人工接种的11科39种植物中能侵染6科14种植物,在克里芙兰烟上产生系统坏死,在小白菜、花椰菜等十字花科植物上产生系统花叶或为隐症,在昆诺藜等藜科植物上为局部侵染。在番红花病叶、球茎及克里芙兰烟病叶组织中观察到卷轴状和片层状聚集的风轮状内含体。免疫吸附和免疫修饰电镜观察结果显示,SA与芜菁花叶病毒((TuMV)具有紧密的血清学关系。根据这些特征将SA鉴定为TuMV的一个分离物。这是TuMV侵染番红花的首次报道。     

Virulence and Molecular Diversity in Cochliobolus sativus

ABSTRACT Spot blotch, caused by the fungal pathogen Cochliobolus sativus, is an important disease of barley in many production areas of the world. To assess genetic diversity in this pathogen, a worldwide collection of C. sativus isolates was evaluated for virulence on barley and DNA polymorphism. Three pathotypes (0, 1, and 2) were identified among the 22 isolates tested in this study and the 36 isolates characterized previously on three barley differentials (ND5883, Bowman, and NDB112) that differ in their resistance to C. sativus. Pathotype 2, which exhibits high virulence on cv. Bowman, was only found in North Dakota, whereas the other two pathotypes occurred in many other regions of the world. Genetic diversity of the 58 C. sativus isolates, together with isolates of three related pathogenic Cochliobolus spp. (C. heterostrophus, C. carbonum, and C. victoriae) was analyzed using amplified fragment length polymorphism (AFLP) markers. A total of 577 polymorphic AFLP markers were recorded among the 70 isolates of the four Cochliobolus spp. using eight primer combinations. Cluster analysis revealed distinct groups corresponding to the four different species, except in one case where race 0 of C. carbonum was placed in an outgroup that may belong to a different species. In C. sativus, 95 polymorphic AFLP markers were detected with the eight primer pairs used, and each isolate exhibited a unique AFLP pattern. Allelic diversity in the pathotype 2 group was lower (0.10) than in the pathotype 0 (0.23) and pathotype 1 (0.15) groups, indicating that pathotype 2 may have arisen more recently. Cluster analysis did not reveal a close correlation between pathotypes and AFLP groups, although two AFLP markers unique to pathotype 2 isolates were identified. This low correlation suggests that genetic exchange may have occurred through parasexual recombination in the fungal population. Some isolates collected from different regions of the world were clustered into the same AFLP group, suggesting that migration of the fungal pathogen around these regions has occurred.     

Isolation and Characterization of an Endopolygalacturonase from Cochliobolus sativus and a Cytological Study of Fungal Penetration of Barley

ABSTRACT Endopolygalacturonase (EPG) of Cochliobolus sativus was produced in shake culture and purified by high-performance liquid chromatography. The enzyme had a molecular mass of 34,000 Da, an isoelectric point in the range of 9.0 to 9.5, exhibited endo activity, was nongly-cosylated, and was inhibited by polygalacturonase-inhibiting proteins from bean, pear, and tomato. The amino terminus contained a 14 amino acid region homologous to a region at the N terminus of an EPG of C. carbonum. C. sativus EPG-specific monoclonal antibodies (MAbs) were generated. Western blot analysis confirmed the specificity of the antibodies for the EPG and detected the enzyme in an extract from Hordeum vulgare (cv. Golden Promise) leaf segments infected with C. sativus. Using conventional immunogold and enzyme-gold cytochemical methods, homogalacturonan, esterified pectin, and cellulose were localized in healthy and infected barley leaf epidermis at the electron microscope level. Additionally, the leaf cell wall polysaccharides recognized by purified C. sativus EPG were localized at the electron microscope level, using the purified enzyme as a primary cytochemical reagent, followed by a gold-labeled MAb specific for the enzyme. Loss of polygalacturonic acid in the vicinity of the invading pathogen was visualized cytochemically at the electron microscope level. These observations suggest the involvement of EPG during host penetration by the fungus.