The effects of Phoma macrostoma on nontarget plant and target weed species

Phoma macrostoma 94-44B was evaluated against 94 plant species in 34 botanical families, of economically important agricultural, horticultural and ornamental species, as well as target and nontarget weeds. Fifty-seven species from 28 families were found to be resistant to P. macrostoma, while 38 species from 12 families, six of which also contained resistant species, were found to be susceptible. Those families comprising both susceptible and resistant species included the Asteraceae, Brassicaceae, Fabaceae, Lamiaceae, Plantaginaceae and Rosaceae with the foremost three containing the largest numbers of susceptible species. P. macrostoma was pathogenic to many dicotyledonous plant species, but nonpathogenic to monocots. Commercial applications for weed management in turfgrass, agriculture, horticulture and forestry seem probable, while domestically management of weeds in lawns, transplanted ornamental and annual flowering species may provide alternative markets.     

黄果龙葵和龙葵染色体制片优化及核型分析

该实验以黄果龙葵和龙葵的根尖为实验材料,进行不同的预处理、固定和解离,确定出各种材料适合于核型分析的制片方法。结果表明:龙葵于15℃条件下经0.05%秋水仙素预处理2.5h,固定后用1mol/L HCl酸解后,染色观察,得到的染色体分散,易于染色体计数和形态观察。用此方法对黄果龙葵和龙葵进行核型分析,结果发现:黄果龙葵和龙葵都属于小型染色体,黄果龙葵为四倍体,核型公式为K(4n)=48=4sm+44m,核型不对称系数为56.22%,属于2B核型。龙葵为六倍体,核型公式为K(6n)=72=72m,核型不对称系数为55.89%,属于1B核型。     

地黄内生放线菌的分离及地黄轮纹病拮抗菌Streptomyces folium leaf-16的新种鉴定

药用植物内生放线菌具有合成天然活性化合物的潜力,放线菌新种是寻找新型抗生素先导化合物的一个重要来源。【目的】挖掘药用植物地黄内生放线菌资源,并对地黄轮纹病拮抗菌株leaf-16进行新种鉴定。【方法】本研究采用五步消毒法分离河南道地药材地黄的内生放线菌,以地黄轮纹病原真菌草茎点霉(Phoma herbarum)为指示菌,采用平板对峙法筛选对该病菌有抑制作用的菌株,16S rRNA基因测序发现一株抗地黄轮纹病的放线菌新种leaf-16。通过形态、生理生化、细胞壁化学组分和分子生物学等特征对菌株leaf-16进行多相分类学鉴定。【结果】经平板对峙实验得到8株抗地黄轮纹病的放线菌,其中菌株leaf-16经16S rRNA基因测序、形态比较、生理生化、化学组分和分子生物学以及DNA-DNA杂交分析,确定菌株leaf-16为1株链霉菌新种,并命名为Streptomyces folium。【结论】菌株leaf-16为1株链霉菌新种,具有抑制地黄轮纹病原真菌的活性,为进一步分离新型抗地黄轮纹病的生物制剂奠定物质基础。     

Antibacterial constituents from the berries of Piper nigrum

Piper nigrum finds an extensive application in antibacterial preparations belonging to Ayurvedic system of medicine. A bioguided extraction and fractionation of the petroleum ether extract of the berries of P. nigrum afforded 2E, 4E, 8Z-N-isobutyleicosatrienamide (1), pellitorine (2), trachyone (3), pergumidiene (4) and isopiperolein B (5). Pergumidiene and trachyone are isolated for the first time from P. nigrum. All the isolated compounds were active against Bacillus subtilis, Bacillus sphaericus, and Staphylococcus aureus amongst Gram +ve bacteria, and Klebsiella aerogenes and Chromobacterium violaceum among Gram –ve bacterial strains.     

Plant colonization and environmental fate of the biocontrol fungus Phoma macrostoma

Several isolates of the fungus Phoma macrostoma demonstrated bioherbicidal activity against dandelion seedlings when applied to soil. Weed control ranged from 36 to 100% depending on the isolates and the doses applied. Using microbiological and molecular genetic techniques, the ability of these isolates to colonize target, and nontarget plants and to disperse and persist in soil were determined. PCR primers highly specific to the biocontrol isolates of P. macrostoma, were used to detect the isolates at rates of application between 4 and 1000 g/m². Based on the results from representative isolates tested, it was concluded that P. macrostoma colonized root tissues of both resistant and susceptible crop species and a susceptible weed species grown in treated soil, and the frequency of fungal isolation declined with time. It was occasionally detected on untreated plant tissues, which may have resulted from either natural occurrences on seed, or contamination of soil. The biocontrol fungus appeared to have limited mobility in the soil since it was not often detected away from the area where it was placed. It persisted in the soil at detectable levels for up to 4 months, but then its presence declined with time. One year post application, P. macrostoma was either not present or significantly reduced in both soil and plant samples depending on the year of sampling. The results suggested that the isolates of P. macrostoma used for biological weed control would have minimal environmental impact due to its ubiquitous nature, limited mobility, and weak persistence over seasons.     

少花龙葵与黄果龙葵染色体核型分析

利用DAPI显带技术对少花龙葵和黄果龙葵染色体进行了核型分析。结果表明,少花龙葵染色体数目为24,为二倍体,核型公式为K(2n)=24=6sm+18m;黄果龙葵染色体数目为48,为四倍体,核型公式为K(4n)=48=48m,并进一步构建了这两个种的核型模式图。此外,还初步探讨了染色体的DAPI带型及其异染色质的分布。为中国龙葵的系统分类和进化趋向研究,以及育种和资源的开发利用提供帮助。     

Assessment ofTrichogramma species for biological control of forest lepidopteran defoliators

In a laboratory study, we determined the potential of threeTrichogramma (Hymenoptera: Trichogrammatidae) species,T. brassicae Bezdenko,T. minutum Riley andT. nr.sibiricum Sorokina, for biological control against six species of forest lepidopteran pests, black army cutworm, hemlock looper, eastern spruce budworm, western spruce budworm, white-marked tussock moth, and gypsy moth. Females of each parasitoid species were offered eggs from each of the six host species. Parasitization and the effect of the host species on the emerging progeny were examined and recorded.Trichogramma minutum had the broadest host range and successfully parasitized four host species out of the six offered.Trichogramma nr.sibiricum had the narrowest host range and parasitized only two species of hosts. Of the six host species, black army cutworm was the most preferred by all threeTrichogramma species; white-marked tussock moth and gypsy moth were not parasitized by any parasitoids. There was a positive correlation between the size of female offspring and their corresponding egg complement in all three parasitoid species. The developmental time of parasitoids from egg to adult was influenced by both the parasitoid and host species. Our results suggest thatT. minutum has the greatest potential for biological control against various forest lepidopteran pests and that the black army cutworm may be the best target candidate for further study.     

Essential oil composition of two endemic Centaurea species from Turkey, Centaurea mucronifera and Centaurea chrysantha, collected in the same habitat

The essential oils of two endemic Centaurea species from Turkey, C. mucronifera and C. chrysantha, collected in the same habitat, have been studied. The main compounds of the former were germacrene D (29.3%), β-eudesmol (17.4%) and β-caryophyllene (7.3%), while in the latter germacrene D (27.4%), caryophyllene oxide (9.5%) and bicyclogermacrene (5.4%) were detected among its major constituents. The two species produced many similar compounds in their essential oils that could be justified by the similar ecological conditions of their habitat, but also many differences were found that could confirm their taxonomic separation.     

Morphological and molecular characterization of somatic hybrid plants between Lycopersicon esculentum and Solanum nigrum

Summary Mesophyll protoplasts of tomato (Lycopersicon esculentum Mill. var. cerasiforme) and of an atrazine-resistant biotype of black nightshade, (Solanum nigrum L.), were fused by using polyethylene glycol/dimethyl sulfoxide (PEG/DMSO) solution and three somatic hybrid plants, each derived from a separate callus, were recovered. A twostep selection system was used: (1) protoplast culture medium (modified 8E) in which only tomato protoplasts formed calluses; and (2) regeneration medium (MS2Z) on which only S. nigrum calluses produced shoots. These selective steps were augmented by early isozyme analysis of putative hybrid shoots still in vitro. Phosphoglucoisomerase (PGI) and glutamate oxaloacetate transaminase (GOT) mapped to five loci on four chromosomes in tomato confirmed the hybrid nature of the nuclei of regenerated shoots. The somatic hybrid plants had simple leaves, and intermediate flower and bud morphology, but anthesis was reduced to 5% due to premature bud abscission and the pollen grains were non-viable. Southern DNA blot hybridization using a pea 45 S ribosomal RNA gene probe reconfirmed the hybrid nature of the nuclear genome of the three plants. A ³²P-labeled probe of Oenothera chloroplast DNA (cpDNA) hybridized to cpDNA restricted with EcoRI or EcoRV indicated the presence of the tomato cpDNA pattern in all three hybrids. Likewise, the plants were all found to be atrazine sensitive. Analysis with two mitochondrial (mt)DNA-specific probes, maize cytochrome oxidase subunit II and PmtSylSa8 from Nicotiana sylvestris, showed that, in addition to typical mitochondrial rearrangements, specific bands of both parents were present or missing in each somatic hybrid plant.Michigan Agricultural Experiment Station Journal Article No. 12433     

基于三代测序的大秃马勃的rDNA ITS鉴定及其基因组生物信息学分析

[背景]马勃是著名的传统可食用药用真菌,具有多种药理作用,包括抗菌、抗炎、止咳、抗肿瘤和抑制细胞增殖等.目前关于马勃的研究多集中在活性物质的分离提取及其药理药效上,而对马勃基因组遗传信息知之甚少.[目的]获得马勃真菌的基因组遗传信息,挖掘潜在具有工业应用价值的功能基因.[方法]联合使用Illumina二代测序技术和Pa...     

基于实验种群两性生命表的伊氏叶螨在番茄和龙葵上的适应性评价

【目的】伊氏叶螨是一种世界性入侵害螨,在我国的潜在危害目前尚不明确。本研究旨在明确其在我国对2种常见茄科寄主植物番茄和龙葵的适应性,为伊氏叶螨的科学防治提供理论依据。【方法】在温度(25±2)℃、相对湿度(70±5)%、光暗比L∶D=16 h∶8 h的实验室条件下,应用两性生命表方法测定伊氏叶螨在番茄和龙葵上的相关生物学参数,评估其对番茄和龙葵的适应性。【结果】取食番茄的伊氏叶螨的成螨前期为14.41 d,显著长于取食龙葵的12.08 d (p<0.05);取食番茄和龙葵时成螨均可存活20 d以上,雌成螨产卵前期分别为1.51和1.43 d。取食番茄的伊氏叶螨种群的内禀增长率、周限增长率、净增殖率、平均世代周期分别为0.17 d^-1、1.18 d^-1、37.17和21.85 d;而取食龙葵的则分别为0.19 d^-1、1.21 d^-1、34.55和18.63 d。【结论】伊氏叶螨在番茄和龙葵上均能完成完整的生活史,且对龙葵的适应度高于番茄。因此推测龙葵可能比番茄更适合作为伊氏叶螨入侵后的寄主植物。     

岩高兰分泌组织显微结构特征及其挥发性成分分析

采用光学显微镜、扫描电镜对岩高兰茎、叶表面、断面及其分泌组织特征进行观察,采用水蒸汽蒸馏法、溶剂提取取法-水蒸汽蒸馏法、溶剂提取法对岩高兰挥发性成分进行提取,并通过GC-MS法对挥发性成分进行对比分析。结果表明:(1)岩高兰的分泌组织有腺毛和分泌细胞;叶表面有头状腺毛,由1个基细胞、1~3个柄细胞、1~4个头部细胞组成;茎髓中含有油细胞,呈黄棕色。(2)水蒸气蒸馏法和溶剂提取法-水蒸气蒸馏法提取率较低,但气味与原植物相近,共有成分10种,多带有芳香气味;溶剂提取法得率较高,但杂质较多。(3)3种方法所得挥发油中有顺-α,α-5-三甲基-5-乙烯基四氢化呋喃-2-甲醇和植酮2个共有成分;从茎和叶挥发性成分中分别鉴定出27和32种化合物,共有成分15种,含量较高的有三十四烷、二十九烷、γ-毕澄茄烯等。研究认为,分泌组织与岩高兰香气物质产生密切相关,其分泌物的组成和含量对香气有重要影响,正是这些有芳香气味的化学成分的有机结合以及自身生长的环境因素才形成了岩高兰的特征香味,此研究结果可为这一香料资源的研究与开发利用奠定基础。