烟草对烟粉虱的抗性与烟草化学成分的相关性

为探明烟草对烟粉虱Bemisia tabaci(Gennadius)的抗性机制,分别测定了不同烟草品种的叶绿素相对含量、鲜烟叶及烤后烟叶的化学成分含量,并分析了烟草抗虫性与烟草化学成分的关系.结果表明,中部叶片叶绿素含量与烟粉虱数量呈负相关,相关系数达到了显著水平;鲜烟叶化学成分钾氯比、糖碱比、氮碱比、还原糖、烟碱、蛋...     

烟草内生菌对烟草根结线虫病的防治效果

从烟草中筛选到几株内生菌进行防治根结线虫的盆栽试验,以研究其防治效果.结果表明,内生细菌发酵液的防治效果优于内生细菌菌体,内生放线菌则相反.内生菌普遍对植物具有促生作用,但内生菌菌体的促生效果优于内生菌的发酵液.H3号内生细菌对根结线虫防治效果最好,病情指数为4.16,防效为91.68%,明显优于对照,优于阿维菌素处理,H3号内生细菌处理的烟草形态指标明显优于阿维菌素处理.

Abstract：

Several tobacco endophyte strains were screened out, and their controlling effect against tobacco root-knot nematodes was studied with pot experiment. The fermentation broth of endophytic bacteria was more effective than the bacterial thallus, while that of endophytic actino-mycetes was less effective than the actinomycete fermentation broth. All test endophytes promoted tobacco growth, and the promotion effect of their thalli was better than that of their fermentation broths. Endophytic bacterial strain H3 was the best in controlling tobacco root-knot nematode dis-ease, with 91.68% controlling effect and a disease index of 4. 16, much better than the treat-ments CK and avermectin. Moreover, the morphological feature of tobacco plant treated with H3 was better than that treated with avermectin.     

Occupational exposure to bidi tobacco increases chromosomal aberrations in tobacco processors

In India, workers engaged in processing of tobacco for the manufacture of bidis (the indogenous substitute for cigarettes) are chronically exposed to tobacco flakes and dust via the cutaneous and nasopharyngeal routes. Hence, workers in a tobacco processing factory were monitored for chromosomal aberrations (CA) using peripheral blood lymphocytes as the test system. Cytogenetic analysis revealed a significant increase in deletion fragments and chromatid gaps in the exposed group. The frequency of aberrant metaphases and the proportion of individuals with CA were significantly higher in workers than in controls, indicating that occupational exposure to tobacco imposes considerable genotoxicity among tobacco processors.     

烟草在PVYN病毒与烟蚜作用下对高CO2浓度的响应

以CO2浓度为主处理因子,研究了加倍CO2浓度和对照大气CO2浓度条件下,烟蚜、马铃薯Y病毒N株(PVYN)以及二者共同作用下烟草各指标的响应。结果表明,在当前CO2浓度条件下,PVYN、烟蚜及两者联合作用对烟草生物量影响不显著;而在未来高CO2浓度条件下,PVYN、烟蚜及两者联合作用对烟草生物量影响很大。CO2浓度升高后,PVYN和蚜虫二者联合作用显著降低烟草产量,危害加重,高CO2的"肥料"作用被极大地削弱。在有烟蚜、PVYN以及两者共同作用时烟草的化学物质及主要的次生代谢物烟碱的含量对CO2浓度升高的响应也发生一定的变化,表现在:高CO2浓度条件下,蚜虫、蚜虫与PVYN共同作用显著增加了烟草的含氮量;显著减少了烟叶含糖量;PVYN及其与蚜虫共同作用显著升高叶片可溶性蛋白含量;当高CO2浓度下,各处理的烟草烟碱含量均显著下降,而且PVYN感染的烟叶烟碱含量无论在哪一种CO2浓度条件下,都比无毒无虫的对照烟叶烟碱含量升高。结果显示,烟蚜和马铃薯Y病毒N株(PVYN)对烟草的产量、营养物质及防御物质都有影响;CO2浓度升高对烟草的生长有促进作用,增加了烟草的产量,但蚜虫的危害和PVYN感染使烟草产量下降,在高CO2浓度条件下,烟蚜和PVYN共同作用相对于目前CO2浓度对烟草产量的危害加重。     

Neighborhood-based tobacco advertising targeting adolescents.

Adolescent tobacco use remains a serious problem, and adolescents may be particularly receptive to the glamorous images tobacco companies use in advertisements. A relatively new form of neighborhood-based outdoor advertising, the illuminated bus-stop-shelter billboard, was studied to determine tobacco companies'' use of this medium. We hypothesized that in 2 distinct San Francisco, California, neighborhoods, 1 predominantly white and the other mostly Latino, we would find a predominance of tobacco advertising on these billboards in both neighborhoods, that tobacco advertisements would be more prevalent in the minority Latino neighborhood, and that tobacco advertising would target adolescents in both neighborhoods. Each bus-stop-shelter billboard advertisement in the study areas from April 1992 to March 1993 was recorded. The type and frequency of products advertised and qualitative content of tobacco advertisements were analyzed. Adolescents'' possible exposure to these advertisements was noted. Our main outcome measures were the percentage of tobacco advertising, possible adolescent exposure to this advertising, and themes of the tobacco advertisements. About 10% of all bus-stop-shelter billboard advertisements in each area promoted tobacco use. Possible exposures to these advertisements were greater in the Latino neighborhood because of a greater adolescent population. Qualitative analyses of tobacco advertisements suggested that adolescents are the primary targets. We urge physicians and educators to explicitly address this form of tobacco advertising, and we urge a ban on neighborhood-based tobacco advertising.     

Saccharopine from tobacco leaves

5-Acetoamino-2-hydroxyvaleric acid, (5-AHV) was metabolized to δ-acetylornithine in tobacco leaves. On the other hand, δ-acetylornithine fed to tobacco leaves was metabolized into at least 5 components, one major component being 5-AHV. These results show that tobacco plant has a reversible metabolic pathway between 5-AHV and δ-acetylornithine.     

烟蒜轮作与套作对烤烟产量及根际土壤磷组分的影响

通过大田小区试验,研究烟蒜轮作、套作对烤烟产量和土壤不同形态磷的影响.结果表明： 烟蒜轮作、套作下烤烟产量和上中等烟比例较烤烟单作显著提高,下部叶成熟期根际土壤有效磷含量分别是烤烟单作的1.3和1.7倍.不同种植方式根际和非根际土壤无机磷组分含量均以O-P和Fe-P含量最高,Ca₂-P和Al-P次之,Ca₈-P和Ca₁₀ -P含量最低.与烤烟单作和烟蒜套作处理相比,烟蒜轮作在上部叶成熟期根际土壤Ca₂-P含量最低,Ca₈-P在下部叶成熟期含量最低,Ca₁₀-P含量在中部叶成熟期最低.烟蒜轮作和套作在下部叶成熟期和中部叶成熟期根际土壤Al-P含量分别是烤烟单作的1.6和1.9倍、1.2和1.9倍.烟蒜轮作和套作根际土壤O-P含量均显著低于烤烟单作.烟蒜轮作较烟蒜套作更能活化土壤中难溶的O-P、Ca₁₀-P和高稳性有机磷,提高烤烟产量和中上等烟比例.     

Binding of tobacco mosaic virus to membrane material isolated from tobacco leaves.

Binding of tobacco mosaic virus (TMV) to disrupted tobacco leaf membrane was studied. Membrane isolated from tobacco leaves was treated successively with (NH4)2SO4, Li-diiodosalicylate and then pronase. TMV-binding substance was thus isolated in a soluble form. From enzymatic digestion experiments, it was suggested that the binding substance was composed of lipid and carbohydrate.     

Intracellular inclusions in epidermal cells of tobacco infected by tobacco rattle virus

Internal symptoms in epidermal cells of tobacco rattle virus infected tobacco were investigated. Ring-, elipsoid- and spindle-shaped inclusions were found in the period between the fourth and thirtieth day after inoculation of Samsun seedlings.     

Antimicrobial peptaibols induce defense responses and systemic resistance in tobacco against tobacco mosaic virus

Trichoderma spp. are well-known biocontrol agents because of their antimicrobial activity against bacterial and fungal phytopathogens. However, the biochemical mechanism of their antiviral activity remains largely unknown. In this study, we found that Trichokonins, antimicrobial peptaibols isolated from Trichoderma pseudokoningii SMF2, could induce defense responses and systemic resistance in tobacco (Nicotiana tabacum var. Samsun NN) against tobacco mosaic virus (TMV) infection. Local Trichokonin (100 nM) treatment led to 54% lesion inhibition, 57% reduction in average lesion diameter and 30% reduction in average lesion area in systemic tissue of tobacco compared with control, indicating that Trichokonins induced resistance in tobacco against TMV infection. Trichokonin treatment increased the production of reactive oxygen species and phenolic compounds in tobacco. Additionally, application of Trichokonins significantly increased activities of pathogenesis-related enzymes PAL and POD, and upregulated the expression of several plant defense genes. These results suggested that multiple defense pathways in tobacco were involved in Trichokonin-mediated TMV resistance. We report on the antivirus mechanism of peptaibols, which sheds light on the potential of peptaibols in plant viral disease control.     

Structure of tobacco genes encoding thaumatin-like proteins

Two tobacco genes encoding thaumatin-like proteins were cloned and sequenced. Both genes are expressed after infection of tobacco with tobacco mosaic virus (TMV). Comparison of the upstream sequences of these genes with those of other TMV-inducible tobacco genes revealed limited regions of homology.     

A new multigene family inducible by tobacco mosaic virus or salicylic acid in tobacco.

A previously undescribed cDNA family was isolated from tobacco challenged with tobacco mosaic virus (TMV). A cDNA library was constructed with mRNA from upper leaves of Xanthi nc tobacco plants that had been inoculated with TMV on the lower leaves 11 days previously. The library was screened differentially with radiolabeled cDNA synthesized with mRNA from upper, uninoculated leaves of either TMV-inoculated or mock-inoculated tobacco plants. The new cDNA family, designated SAR8.2, had at least five expressed members, one or more of which were inducible by TMV inoculation and by salicylic acid treatment. The cDNAs encoded small, highly basic proteins containing N-terminal hydrophobic signal peptides and highly conserved cysteine-rich C-terminal domains. One of the SAR8.2 family members contained a direct repeat of the C-terminal domain in tandem. Hybridization of SAR8.2 cDNA to tobacco genomic DNAs indicated a gene family of 10-12 members.     

Analysis of acidic and basic chitinases from tobacco and petunia and their constitutive expression in transgenic tobacco

cDNA clones of messenger RNAs for acidic and basic chitinases were isolated from libraries of tobacco mosaic virus-infected Samsun NN tobacco and petunia. The tobacco cDNA clones for acidic chitinase fell into two different groups, whereas all petunia cDNA clones had the same sequence. Also, tobacco genomic clones were isolated and one was characterized. This genomic clone, corresponding to one of the cDNA clones, showed that this acidic chitinase gene contains two introns. The amino acid sequences of the acidic chitinases from tobacco, as deduced from the cDNA clones, fully agreed with partial sequences derived from peptides obtained from purified tobacco-derived pathogenesis-related proteins PR-P and PR-Q. The deduced amino acid sequences showed that PR-P and PR-Q are 93 and 78%, respectively, identical to the petunia enzyme. All deduced chitinase sequences indicated the presence of an NH2-terminal, highly hydrophobic signal peptide. In addition, the polysaccharide-binding domain present at the NH2-terminus of basic chitinases from mature tobacco is not present in these acidic chitinases. Furthermore, the complete coding sequence for the petunia chitinase, constructed downstream of the cauliflower mosaic virus 35S promoter, was used to transform tobacco. The resulting chimeric gene was constitutively expressed, and the petunia enzyme was targeted to the extracellular fluid. In contrast, a basic chitinase of tobacco, expressed from a chimeric gene, was found in total leaf extracts but not in preparations of extracellular fluid.     

烟草中多酚氧化酶(PPO)的特征

烟草中的多酚氧化酶介导的褐变会影响烟叶和烟丝的色泽和内在质量,因此对其特性的研究,以及活性的控制成为多年来的研究热点。本文从其生物发生模型、分子结构、生物化学和光谱学特征与植物抗病和机械损伤的关系,多酚氧化酶的抑制、多酚氧化酶的应用等方面着手,对近几年来烟草中PPO研究的最新成果进行总结和回顾,对一些有争议的问题进行了探讨,并对未来PPO研究的方向和领域进行了展望。     

镉和铅污染对烤烟根区土壤微生物及烟叶品质的影响

通过盆栽试验,研究了Cd和Pb污染对烤烟根区微生物和烟叶品质的影响.结果表明,随着Cd、Pb处理浓度的增加,烤烟根区4种微生物数量均呈减少趋势;低浓度Cd(≤10 mg·kg^-1)和Pb(≤300 mg·kg^-1)下,烤烟根区4种微生物数量降幅最大;烤烟烟叶中品质指标糖/碱比和氮/碱比升高,化学成分组成趋于不协调,不利于烟叶香味的形成.烟叶K含量与Cd和Pb污染浓度呈负相关,与Cd污染下根区钾细菌数量呈显著(或极显著)正相关,与Pb污染根区钾细菌数量相关不显著.     

不同品种烟草花粉电子显微镜观察

通过对10个烤烟品种、8个晒烟品种、2个野生种的花粉进行扫描电子显微镜观察,发现同为烤烟或晒烟的烟草,其花粉的形态、大小、外壁纹饰比较稳定。野生烟在供试种中具有独特的细网状外壁纹饰,是鉴别野生烟与非野生烟的一条有效途径。     

Enzymatic reactivity of neutrophils in tobacco smokers

Activity of 8 enzymes in neutrophils of tobacco smokers was assayed with histochemical semiquantitative technique. An increase in the activity of acid phosphatase and beta-glucuronidase was found in the short period of tobacco smoking lasting 6.5 years on the average. Low activity of beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, non-specific alpha-naphtolesterase and LAP was found in the individuals smoking tobacco for 18.5 years. The authors suggest that carcinogenic action of the tobacco smoke is also related to the disorders in neutrophils enzymes activity.     

Growing better tobacco

Proper application of knowledge concerning the nutritional requirements of tobacco is an important factor in the production of better crops.     

Genotoxicity of tobacco smoke and tobacco smoke condensate: a review

This report reviews the literature on the genotoxicity of mainstream tobacco smoke and cigarette smoke condensate (CSC) published since 1985. CSC is genotoxic in nearly all systems in which it has been tested, with the base/neutral fractions being the most mutagenic. In rodents, cigarette smoke induces sister chromatid exchanges (SCEs) and micronuclei in bone marrow and lung cells. In humans, newborns of smoking mothers have elevated frequencies of HPRT mutants, translocations, and DNA strand breaks. Sperm of smokers have elevated frequencies of aneuploidy, DNA adducts, strand breaks, and oxidative damage. Smoking also produces mutagenic cervical mucus, micronuclei in cervical epithelial cells, and genotoxic amniotic fluid. These data suggest that tobacco smoke may be a human germ-cell mutagen. Tobacco smoke produces mutagenic urine, and it is a human somatic-cell mutagen, producing HPRT mutations, SCEs, microsatellite instability, and DNA damage in a variety of tissues. Of the 11 organ sites at which smoking causes cancer in humans, smoking-associated genotoxic effects have been found in all eight that have been examined thus far: oral/nasal, esophagus, pharynx/larynx, lung, pancreas, myeoloid organs, bladder/ureter, uterine cervix. Lung tumors of smokers contain a high frequency and unique spectrum of TP53 and KRAS mutations, reflective of the PAH (and possibly other) compounds in the smoke. Further studies are needed to clarify the modulation of the genotoxicity of tobacco smoke by various genetic polymorphisms. These data support a model of tobacco smoke carcinogenesis in which the components of tobacco smoke induce mutations that accumulate in a field of tissue that, through selection, drive the carcinogenic process. Most of the data reviewed here are from studies of human smokers. Thus, their relevance to humans cannot be denied, and their explanatory powers not easily dismissed. Tobacco smoke is now the most extreme example of a systemic human mutagen.