甘蓝型油菜品种（系）对菌核病抗（耐）病性的测定

用草酸浸根和黑麦粒接种两种方法分别对来自中国和加拿大等国的１５个春性和１６个冬性、半冬性甘蓝型油菜品种（系）进行了抗（耐）菌核病的鉴定。结果没有发现高抗类型，但是甘蓝型油菜品种（系）之间存在着感染菌核病轻重程度的显著差异。     

Resistance to Rhizoctonia solani AG‐2‐2 (IIIB) in creeping bentgrass plants transformed with pepper esterase gene PepEST

A pepper esterase (PepEST) gene was introduced into creeping bentgrass (Agrostis stolonifera) by Agrobacterium‐mediated transformation. Purified recombinant PepEST proteins were sufficient to inhibit the growth of the fungal pathogens Rhizoctonia solani AG2‐2 (IIIB) (causing brown patch) and Sclerotinia homoeocarpa (dollar spot), but not the oomycete responsible for pythium blight, Pythium aphanidermatum. PepEST proteins were most effective against R. solani. After genetic transformation of creeping bentgrass with PepEST, the genomic integration of transgenes bar and PepEST was confirmed by Southern blot analysis, and their expression was also validated by northern blot and western blot analyses. Disease severity on R. solani‐inoculated leaves of transgenic plants was <10% compared to ca. 50% in non‐transgenic plants. Microscopic observation of infected leaves indicated that PepEST inhibited the growth of hyphae upon fungal infection.     

A nested‐PCR method for rapid detection of Sclerotinia sclerotiorum on petals of oilseed rape (Brassica napus)

This study established a quick and accurate method to detect petal infection of oilseed rape (Brassica napus) by Sclerotinia sclerotiorum using a nested‐PCR technique. DNA samples were extracted from each petal using a microwave method, followed by two rounds of PCR amplification. The first‐round PCR amplification was performed using the universal fungal primer pair ITS4/ITS5, and the second‐round amplification with a specific primer pair XJJ21/XJJ222, which was designed using the single‐nucleotide polymorphisms among nuclear rDNA ITS sequences of Sclerotinia spp., Botrytis spp. and other selected fungi. The established technique is rapid and inexpensive, and has a high degree of specificity and sensitivity. This assay can distinguish Sclerotinia spp. from other fungi, including Botrytis cinerea, a closely related and frequent cohabitant on oilseed rape petals, and can detect 50 fg genomic DNA, five ascospores of S. sclerotiorumin vitro or 50 ascospores of S. sclerotiorum on one petal in approximately 6 h, even in the presence of a high background of oilseed rape DNA. This technique was successfully applied in detecting natural petal infections.     

In vitro and in vivo antifungal activity of synthetic pure isothiocyanates against Sclerotinia sclerotiorum

BACKGROUND: Isothiocyanates (ITCs) released by the enzymatic hydrolysis of glucosinolates in the Brassicaceae are potentially useful for controlling fungal pathogens. In vitro activity of pure ITCs against Sclerotinia sclerotiorum (Lib.) de Bary was studied by adding them to glass filters in petri dishes and dissolving them in the growing media. RESULTS: Methyl, allyl and benzyl ITCs were the most fungitoxic of the compounds in bioassays with S. sclerotiorum isolate Ss31. In the volatile phase, mycelial growth was completely inhibited by these three compounds. Aromatic ITCs were less toxic in the petri dishes but were more toxic than aliphatic ITCs when dissolved in the agar. Benzyl ITC exhibited the highest inhibitory effect on sclerotial germination, with an EC₅₀ value of 75.1 µmol L^?1. Butyl and benzyl ITCs reduced apothecial production of S. sclerotiorum by 92.5% at the highest concentration. In in vivo assay, only allyl and 2‐phenylethyl ITCs reduced disease incidence (by 76.7 and 70% respectively) at low concentrations. CONCLUSION: Sclerotinia sclerotiorum in the soil might be suppressed by the higher concentrations of allyl and benzyl ITCs released from decomposition of Brassica juncea, B. carinata, B. nigra and Sinapis spp. Copyright © 2011 Society of Chemical Industry     

Multivariate effects of plant canopy, soil physico-chemistry and microbiology on Sclerotinia stem rot of soybean in relation to crop rotation and urban compost amendment

The effects of canopy, soil physico-chemical and microbiological variables on Sclerotinia stem rot (SSR) on soybean were assessed in two soils (clay loam and sandy loam) using multiple regression and canonical redundancy analysis (RDA) and their partial form to control for the rotation (2 or 3-y-corn/soybean monoculture) and fertilization (mineral/urban compost) or spatial variables effects. The models revealed the minimal sets of variables that best explain the variance of the survival of Sclerotinia sclerotiorum’s sclerotia, carpogenic germination, disease severity and their associations. In clay loam, the 3-y-corn rotation reduced disease severity mainly through the reduction of weed biomass that favoured carpogenic germination. Urban compost has a conducive effect explained by a better soil surface drainage. Additionally, total N was found suppressive to sclerotial survival. In sandy loam, the carpogenic germination was negatively correlated with high C mineralization quotient and aggregate stability but correlated positively with Ca. Sclerotial survival was negatively correlated with pH and Ca, and positively correlated with biological fertility index. Aggregate stability, Ca and pH were associated with the urban compost. The regression and RDA analyses allowed to identify key variables that drived SSR development and explain their relationship with the cultural practices, soil health, as well as the spatial variation of disease variables.     

向日葵菌核病菌核及子囊柄萌发峰期的预测

向日葵菌核病的流行取决于田间菌核量与气候因素的影响。试验研究得知,菌核子囊柄萌发程度在菌核经过一场透雨后与七月底,八月份的降雨量及降雨次数呈正相关,而与此时期的平均温度,降雨间隔期呈负相关。由此建立了预测菌核子囊柄萌发程度的多元回归式为y=65.25—2.58x_1 0.04x_2 2.36x_3-2.10x_4。子囊柄萌发期是进行药剂防治的最有效时期,因此预测子囊柄萌发峰期是防治菌核病的关键。通过多元回归建立预测式为y=76.52-1.38x_1 0.06x_2-1.84x_3-3.86x_4。用上述两式回测前2年的田间实测值其结果与预测值极近。     

论强制要约收购中股东利益的保护

强制要约收购是指当投资者持有某上市公司己发行股份达到一定比例时，收购人依法向全体股东发出收购要约的法律制度。对于收购人和目标公司管理层而言，股东处在弱势地位，因而需要在制度设计上给予特殊保护。对股东利益的保护需要通过规制收购人和目标公司管理层的行为得以实现。木文对此提出了一些建议。     

面向中小企业的PDM需求分析

众所周知,中小企业的核心竞争力是产品的研究和开发能力,这是企业可长期持续生存发展的根本能力。为此,结合中小企业的管理特点,分析了中小企业在信息化过程中存在的问题;说明了应用PDM技术是提高中小企业核心竞争能力的必要途径;阐述了中小企业对PDM系统的应用需求和性能要求;指出目前中小企业已具备了实施PDM技术的条件。     

Molecular characterization of <Emphasis Type="Italic">Pythium</Emphasis> group F isolates by ribosomal-and intermicrosatellite-DNA regions analysis

Pythium group F is a ubiquitous, though minor, pathogen in several soilless and soil cultures; investigations were carried out to analyze different regions of the DNA and better understand the nature of this group. Fourty-two isolates were obtained from a variety of plants (cucumber, lettuce, tomato) grown in soil or soilless cultures collected in various countries (Canada, Denmark, France, Norway, Sweden and United Kingdom). All Pythium group F isolates displayed amplified ITS1-5,8S-ITS2 ribosomal DNA region (rDNA) of similar length, whereas polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) revealed that, among the seven enzymes used, polymorphism was only identified with Hin6I. After cloning of ITS1-5,8S-ITS2 rDNA region from Pythium group F isolates that displayed restriction polymorphism patterns with Hin6I, comparisons of sequence and restriction mapping data showed a slight variation consisting in a single base change. Inter Simple Sequence Repeat (ISSR)-PCR method was also used to obtain data related to the entire genome and not only to a single DNA region. It identified repeated motifs in the genome of Pythium group F isolates. Two primers (CAC)₅ and (CCA)₅ detected polymorphism, and isolates were classified among 11 molecular clusters. The genetic diversity of this group was not correlated with the geographical locations or the host plants from which the isolates originated. Polymorphism of Pythium group F isolates pointed out by ISSR is discussed     

湖南省小宗特色农产品产业发展的SWOT分析

产业化和特色化已成为农产品产业发展的趋势.通过对湖南省小宗特色农产品的实地调查与分析,结合产业经济学的相关理念,分析了湖南特色农产品发展中的优势、劣势、机会与威胁,进而为湖南特色农产品产业化发展提出建议和对策.