南方小花蝽对为害蚕豆的三种蚜虫的捕食作用

豆蚜Aphis craccivora、豌豆蚜Acyrthosiphon pisum和豌豆修尾蚜Megoura crassicauda是为害豆科作物的主要害虫。南方小花蝽Orius strigicollis是重要捕食性食蚜天敌,广泛分布于我国南方。为明确南方小花蝽对豆科作物上3种蚜虫的捕食作用和生物防治潜能,本研究在实验室条件下,测定了南方小花蝽对3种蚜虫的捕食选择性和捕食功能反应。结果表明,南方小花蝽对3种蚜虫的捕食功能反应均符合HollingⅡ模型,不同龄期南方小花蝽对3种蚜虫捕食量由大到小依次为5龄若虫,雌成虫,低龄若虫。对豆蚜的捕食量均大于对豌豆修尾蚜的捕食量,对豌豆蚜的捕食量最小,雌成虫对以上3种蚜虫的日最大捕食量分别为豆蚜63.69头/d、豌豆蚜36.23头/d和豌豆修尾蚜49.26头/d。南方小花蝽对3种蚜虫的寻找效应随蚜虫密度的增加而降低,随小花蝽龄期的增加而升高,相同龄期的南方小花蝽对3种蚜虫的寻找效应由大到小依次为豌豆修尾蚜,豆蚜,豌豆蚜。南方小花蝽对猎物的捕食作用受自身密度的干扰,当猎物密度不变时,随着小花蝽自身密度的增加,单头小花蝽平均捕食量下降,其干扰反应符合H...     

Histological Characterization of Resistance to Uromyces viciae-fabae in Faba Bean

ABSTRACT Components of resistance to the faba bean rust (Uromyces viciae-fabae) were studied at the histological level in seedlings and adult plants of nine faba bean (Vicia faba) lines differing in their level of resistance. Resistance of these lines was previously shown to be characterized macroscopically by an increased latent period, a decreased colony size, and a relatively decreased infection frequency. In some lines, the resistance also was associated with macroscopically visible necrosis. Histological investigations revealed few differences in spore germination and appressorium formation. Significant levels of aborted stomatal penetration by the rust fungus were found on all resistant lines. However, differences among lines were more evident once the stomata were penetrated by the infection structures. Resistance was mainly due to a restriction of haustorium formation with varying levels of early abortion of the colonies, a reduction in the number of haustoria per colony, and smaller colony size. In addition, necrosis of the host cells associated with infection hyphae was detectable in some lines from the beginning of colony development. This microscopically visible necrosis became stronger from 4 days after inoculation, resulting in a reduced growth of the colony. Differences in resistance levels were more marked in adult plants than in seedlings.     

Tolerance of Faba Bean Plants (<Emphasis Type="Italic">Vicia faba</Emphasis>) to Partial Defoliation

Throughout the development of plants, certain biotic and abiotic phenomena can occur which reduce not only the photosynthetic area, but also the growth, depending on the stage of plant development. Responses by plants to defoliation depend on species, the timing of agricultural practices and the intensity level of defoliation. An experiment was carried out in Tunja, Colombia under greenhouse conditions, in order to evaluate the tolerance of faba bean plants (Vicia faba) to partial defoliation. Every week material was removed along each newly emerged leaflet to simulate 50% defoliation. Another group was grown with the entire leaf area to function as a control. As a result of partial defoliation, the specific leaf area, absolute growth rate, relative growth rate and total biomass were reduced, but the leaf weight ratio was increased. In addition, the pattern of dry matter partitioning was altered so that the amount of biomass accumulated was reduced in the roots, but increased in the leaves. Additionally, the partially defoliated plants showed the ability to partly restore the removed leaf area. In this way it could be inferred that the plants of Vicia faba present a moderate capacity to tolerate early defoliation during the vegetative phase.     

Cross-resistance ofAphis gossypii to selected insecticides on cotton and cucumber

Cross-resistance of a fenvalerate-resistant (R-fenvalerate) strain and an imidacloprid-resistant (R-imidacloprid) strain of the cotton aphidAphis gossypii Glover to methomyl, endosulfan and omethoate was determined on cotton and cucumber in the laboratory. The R-fenvalerate strain had been selected for 16 consecutive generations on cotton, and the R-imidacloprid strain for 12. Compared with the susceptible (S) strains, the resistance in the 17th generation of the R-fenvalerate strain to fenvalerate was 29,035-fold on cotton and 700-fold on cucumber, whereas the resistance in the 13th generation of the R-imidacioprid strain to imidacloprid was 4.7-fold on cotton and 3.6-fold on cucumber. The R-fenvalerate strain did not show any cross-resistance to imidacloprid, methomyl or omethoate on cotton and cucumber, but became slightly cross-resistant to endosulfan (RR [resistance ratio] = 5.8 and 7.4 on cotton and cucumber, respectively). On cotton the R-imidacloprid strain became highly cross-resistant to fenvalerate (RR = 108.9) and slightly cross-resistant to methomyl, endosulfan and omethoate (RR = 6.3, 3.0 and 8.5, respectively). In contrast, on cucumber the R-imidacloprid strain became highly cross-resistant to fenvalerate (RR = 33.5) and slightly cross-resistant to methomyl and omethoate (RR = 7.0 and 3.3, respectively), but did not show any cross-resistance to endosulfan. It appears thatA. gossypii of both resistant strains was more resistant to the tested insecticides on cotton than on cucumber, except for imidacloprid —where the resistance on cotton was not significantly different from that on cucumber.     

The Role of Humic Acid Application on Quantitative and Qualitative Traits of Faba Bean (Vicia faba L.)

Gesunde Pflanzen - Humic acid comprises the major part of humic substances and the most important component of soil organic matter (humus) that increases crop yield and quality. This research aimed...     

Physiological and Biochemical Responses of Vicia Faba Plants to Foliar Application of Zinc and Iron

Iron (Fe) and zinc (Zn) are essential nutrients for plant growth and development. Therefore, a pot experiment was conducted to examine the role of Zn and Fe on vegetative growth, photosynthetic pigments, soluble sugars, soluble protein, nitrate reductase (NR), ascorbate peroxidase (APX), catalase (CAT), minerals content, amino acid composition fraction, isozymes, and protein electrophoresis in faba bean plants foliar sprayed with FeSO₄ and ZnSO₄. The results revealed that foliar spray with 1 or 3 g/L of FeSO₄ and ZnSO₄ significantly increased all the abovementioned parameters compared to control plants. The activity of esterase increased with increasing concentration of Fe and Zn as compared to control plants. The most pronounced increase was found in plants treated with 3 g/L ZnSO₄. Three bands of peroxidase isozyme were exhibited with different densities and intensities in all treatments. Three types of modification were observed in the protein patterns of faba bean leaves. Some protein bands disappeared, while other increased and synthesis of a new set of proteins was induced. It could be concluded that foliar spray with the two concentrations (1 or 3 g/L) of ZnSO₄ and FeSO₄ helped faba bean plants to overcome the deficiency in these minerals by producing antioxidant enzymes. Improved faba bean growth through adequate Fe and Zn foliar spray is likely a promising strategy to improve Vicia faba plants.     

菜豆黄花叶病毒中国和叙利亚蚕豆分离物外壳蛋白的序列分析

 病毒病是影响云南省蚕豆生产的重要病害。对采集的蚕豆病毒病标样进行了组织印迹法检测,表明菜豆黄花叶病毒(BYMV)是最主要的病原。据此,以BYMV基因的保守序列设计了一对特异性引物,用BYMV的5个中国云南蚕豆分离物和1个叙利亚蚕豆分离物侵染的蚕豆叶片总RNA为模板,RT-PCR扩增获得了长度为907bp的目标片段。序列分析显示,此片段中包含822bp的外壳蛋白序列。6个分离物间的外壳蛋白核苷酸和推导编码蛋白质的氨基酸序列的同源性分别为86.4%~100.0%和96.7%~100.0%。与GenBank登录的34个具有完整外壳蛋白序列的BYMV分离物进行同源性和系统进化树分析的结果表明,6个分离物在核苷酸和氨基酸水平上与其它分离物的同源性分别为79.1%~97.9%和83.5%~98.5%,BYMV中国蚕豆分离物与日本蚕豆分离物同源性最高。外壳蛋白基因的序列特征揭示,在BYMV中的蚜传相关基序为NAG。     

Molecular Markers Dispute the Existence of the Afro-Andean Group of the Bean Angular Leaf Spot Pathogen, Phaeoisariopsis griseola

ABSTRACT Coevolution of the angular leaf spot pathogen, Phaeoisariopsis griseola, with its common bean host has been demonstrated, and P. griseola isolates have been divided into Andean and Mesoamerican groups that correspond to defined bean gene pools. Recent characterization of P. griseola isolates from Africa has identified a group of isolates classified as Andean using random amplified polymorphic DNA (RAPD), but which are able to infect some Mesoamerican differential varieties. These isolates, designated Afro-Andean, have been identified only in Africa. Random amplified microsatellites, RAPD, and restriction digestion of amplified ribosomal intergenic spacer region were used to elucidate the relationships among the Afro-Andean, Andean, and Mesoamerican groups of P. griseola. Cluster and multiple correspondence analysis of molecular data separated isolates into Andean and Meso-american groups, and the Afro-Andean isolates clustered with Andean isolates. Analysis of molecular variance ascribed 2.8% of the total genetic variation to differences between Afro-Andean and Andean isolates from Africa. Gene diversity analysis revealed no genetic differentiation (G(ST) = 0.004) between Afro-Andean and Andean isolates from Africa. However, significant levels of genetic differentiation (G(ST) = 0.39) were observed between Afro-Andean or Andean isolates from Africa and Andean isolates from Latin America, revealing significant geographical differentiation within the Andean lineage. Results from this study showed that Afro-Andean isolates do not constitute a new P. griseola group and do not represent long-term evolution of the pathogen genome, but rather are likely the consequents of point mutations in genes for virulence. This finding has significant implications in the deployment of resistant bean genotypes.     

东阿拉善-西鄂尔多斯地区特有濒危植物种群斑块变化与优先保护级相关分析

利用3S技术对东阿拉善———西鄂尔多斯地区特有15种濒危植物的面积进行统计处理,绘制出斑块面积变化曲线图,用数字回归方法得出曲线的数学方程。然后找出各植物种斑块面积变化剧烈程度与层次分析法确定的植物优先保护序的相关关系,并进行比较分析。     

Systemic Induction of Peroxidases, 1,3-beta-Glucanases, Chitinases, and Resistance in Bean Plants by Binucleate Rhizoctonia Species

ABSTRACT Inoculation of bean hypocotyls with a nonpathogenic binucleate Rhizoctonia (BNR) species induced systemic resistance and protection of the roots and cotyledons to later challenge with the root rot pathogen Rhizoctonia solani or the anthracnose pathogen Colletotrichum lindemuthianum. Bean seedlings that were treated with BNR 48 h prior to their challenge with R. solani or C. lindemuthianum had few necrotic lesions and reduced disease severity as compared with seedlings not treated with BNR. Treatment with BNR 48 h prior to their challenge also elicited a significant and systemic increase in all cellular fractions of peroxidases, 1,3-beta-glucanases, and chitinases compared with the diseased and control plants. Compared with control plants, total peroxidases and glucanases increased twofold and eightfold, respectively, in all protected bean tissues. BNR 232-CG could not be recovered from the challenged hypocotyls or cotyledons, indicating that there was no contact between the inducer and the pathogen. Both the 1,3-beta-glucanases and the peroxidases were positively correlated with induced resistance.     

Virulence Variation and RAPD Polymorphism in African Isolates of Phaeoisariospis griseola (Sacc.) Ferr., the Causal Agent of Angular Leaf Spot of Common Bean

Fifty four isolates of Phaeoisariopsis griseola, the agent of common bean angular leaf spot disease from the Great Lakes Region of Africa, were characterised according to their virulence behaviour and their molecular patterns. Virulence properties were revealed through the inoculation of 29 genotypes of Phaseolus vulgaris, Phaseolus coccineus and Phaseolus polyanthus. Differences in reaction types revealed high variability among these isolates. Most of them, even when collected within the same location, showed differences in their respective reactions on many plant genotypes. For molecular typing, RAPD amplifications were performed for each isolate using five random primers. Isolates with different patterns were collected within one region. Simultaneously, similar molecular patterns were found in isolates collected at different sites. However, the average of molecular similarity, based on the percentages of shared bands for each isolates pair, was higher among isolates collected within one site. No direct correlation between molecular pattern and pathotype was observed.     

The Measurement of Brown Leaf Spot on Rice

Abstract

To obtain the potential range in disease development, a progressive increase in spore concentration of the imperfect state of Cochliobolus miyabeanus was used on twelve rice varieties differing in their resistance to brown leaf spot. An analysis of the relative contributory effect of increase in lesion size and numbers on the percentage leaf area diseased was used as a basis to develop a quantitative scoring method in chart form for brown spot disease. The chart was aided by the provision of diagrams of the different categories in disease intensity. The usefulness of this disease scoring chart and its limitations are discussed. Other methods of assessment are proposed to overcome the limitations especially in respect of varietal resistance and seedling blights.     

耐草甘膦菜豆耐性分子学机理研究

用耐性菜豆根尖为材料，以λgt10为载体获得了4.8×105个重组噬菌体的cDNA文库。以植物EPSP合成酶基因保守序列合成二段探针，经噬菌体原位杂交筛选出了阳性克隆，并进行了酶切鉴定。测定 cDNA 序列长度为2024个核苷酸，其中编码长1569个核苷酸，共编码523个氨基酸和一个终止密码子，与已发表的其它植物成熟EPSP合成酶氨基酸序列相比具有很高的同源性（≥84.8%），但进入叶绿体运输肽的氨基酸同源性低。以耐性菜豆EPSP合成酶的cDNA序列为模板，用RT-PCR方法扩增感性菜豆EPSP合成酶cDNA片段，并克隆于pUC18质粒上，经测定序列并比较发现:感性菜豆EPSP合成酶cDNA核苷酸序列1737位碱基为G，而耐性的为C，从而表达出的513位氨基酸残基感性的为E，耐性的为Q，表明两种菜豆EPSP合成酶cDNA核苷酸序列一位点的差异是它们对草甘膦耐性不同的原因。     

耐草甘膦菜豆耐性酶学机理的研究

感性、耐性菜豆从萌芽到24d的EPSP合成酶比活性是不同的,但变化规律相似。出苗时比活性较高,10d时降至最低点,随后上升,16d时达到最高点,然后缓慢下降;两种菜豆在生长的同一天酶比活性差异小,最大倍数仅为1.1;用草甘膦处理两种三出复叶时的菜豆1d后酶比活性上升15%～25%。实验测定了经4步纯化,比活性达6219.4nmol· min-1· mg-1蛋白以上的两种菜豆EPSP合成酶的一些酶学性质。PEP是酶的最适底物,感性、耐性 Km(PEP)分别为3.5和7.1μmol· L-1,两者相差2倍,亲和力Ki(草甘膦)分别是6.2和 16.7μmol· L-1,两者相差2.7倍。两种菜豆对草甘膦耐性不同的酶学机理在于耐性菜豆的EPSP合成酶与草甘膦的亲和力小,与酶底物亲和力大;而感性菜豆EPSP酶则与草甘膦的亲和力大,与其底物亲和力小。     

Quantification of Fusarium solani f. sp. phaseoli in Mycorrhizal Bean Plants and Surrounding Mycorrhizosphere Soil Using Real-Time Polymerase Chain Reaction and Direct Isolations on Selective Media

ABSTRACT The capacity of the arbuscular mycorrhizal fungus Glomus intraradices in reducing the presence of Fusarium solani f. sp. phaseoli in bean plants and the surrounding mycorrhizosphere soil was evaluated in a compartmentalized experimental system. Quantification of the pathogen and the symbiont in plant tissues, the soil regions of the mycorrhizosphere (rhizosphere and mycosphere), and the bulk soil was accomplished using specific polymerase chain reaction (PCR) primers in real-time PCR assays, culture-dependant methods, and microscopic determination techniques. Nonmycorrhizal bean plants infected with the pathogen had distinctive Fusarium root rot symptoms, while infected plants previously colonized by G. intraradices remained healthy. The amount of F. solani f. sp. phaseoli genomic DNA was significantly reduced in mycorrhizal bean plants and in each mycorrhizosphere soil compartment. The presence of G. intraradices in the mycorrhizosphere was not significantly modified, although the mycorrhizal colonization of roots was slightly increased in the presence of the pathogen. The results suggest that the reduced presence of Fusarium as well as root rot symptoms are caused by biotic and/or abiotic modifications of the mycorrhizosphere as a result of colonization with G. intraradices.     

The bionomics ofLiriomyza Trifolii on Gypsophila and Bean Leaves

A study was carried out to determine the distribution of feeding and oviposition punctures made byLiriomyza trifolii Burgess on gypsophila(Gypsophila paniculata ) and bean(Phaseolus vulgaris) leaves, and the development times of the immature stages on these plants. The absolute number of punctures per leaf area was much greater on bean leaves than on gypsophila leaves. The number of mines per leaf was also higher on beans than on gypsophila, but the ratio of mines/punctures was higher on gypsophila. Gypsophila leaves were punctured on both sides, but most of the punctures were on the distal third of the upper leaf side. On beans the punctures were dispersed uniformly on the upper side of the leaf. The larval period (±SE) at temperatures of 20, 25 and 30°C was 9.9±0.2, 4.4±0.1 and 3.7±0.1, and 5.5±O. l, 3.7±0.1 and 2.4±0.1 days, on gypsophila and bean, respectively. The pupal period at 17, 20, 25 and 30°C lasted 19.9±0.2, 14.7±0.1, 10.4±0.1 and 7.8±0.1 days, respectively.     

Insect-trapping Hairs on Potato Plants

Abstract

The ability of glandular hairs on the foliage of the wild potato species Solanum polyadenium and S. berthaultii to trap mite and insect pests is illustrated by scanning electron micrographs. Both potato species have hairs with four-lobed heads which release a sticky substance when ruptured. On S. polyadenium these hairs trapped aphids, Colorado beetle larvae and a leafhopper Javasella pellucida. S. berthaultii also has hairs with a sticky droplet at their tips; these hairs trapped such small pests as spider mites, thrips and larval mealybugs. Adult whitefly were not trapped because a powdery wax from the whiteflies coated the hairs. It is suggested that these glandular hairs could help protect potato crops by trapping many foliage pests, including disease vectors.     

Pyricularia grisea Isolates Causing Gray Leaf Spot on Perennial Ryegrass (Lolium perenne) in the United States: Relationship to P. grisea Isolates from Other Host Plants

ABSTRACT Gray leaf spot of perennial ryegrass (prg) (Lolium perenne), caused by the fungus Pyricularia grisea (teleomorph = Magnaporthe grisea), has rapidly become the most destructive of all turf grass diseases in the United States. Fungal isolates from infected prg were analyzed with several molecular markers to investigate their relationship to P. grisea strains found on other hosts. All of the molecular markers used in this study revealed that isolates from prg are very distantly related to those found on crabgrass. Fingerprinting with MGR586 (Pot3) revealed zero to three copies of this transposon in the prg pathogens, distinguishing them from isolates pathogenic to rice, which typically have more than 50 copies of this element. RETRO5, a newly identified retroelement in P. grisea, was present at a copy number of >50 in isolates from rice and Setaria spp. but only six to eight copies were found in the isolates from prg. The MAGGY retrotransposon was unevenly distributed in the prg pathogens, with some isolates lacking this element, some possessing six to eight copies, and others having 10 to 30 copies. These results indicated that the P. grisea isolates causing gray leaf spot are distinct from those found on crabgrass, rice, or Setaria spp. This conclusion was supported by an unweighted pair-group method with arithmetic average cluster analysis of single-copy restriction fragment length polymorphism haplo-types. Fingerprints obtained with probes from the Pot2 and MGR583 transposons revealed that the prg pathogens are very closely related to isolates from tall fescue, and that they share similarity with isolates from wheat. However, the wheat pathogens had fewer copies of these elements than those found on prg. Therefore, I conclude that P. grisea isolates commonly found on other host plant species did not cause gray leaf spot epidemics on prg. Instead, the disease appears to be caused by a P. grisea population that is specific to prg and tall fescue.