建国以来烟草科学技术的发展

(一)烟草传入我国种植约有四百年历史,本世纪前种植的都是晒晾烟类型,烤烟是本世纪初引进栽培,并在解放后迅速发展成为主要类型的。五十年代,烟草科技部门从国外引进试种白肋烟和香料烟,并已在适宜地区形成一定的生产规模。近几年,又在湖北等地试种马里兰烟取得初步成功。一个以烤烟为主体,类型比较齐全多样的烟草类群已在我国形成。建国三十五年来,我国烟草生产虽因种种原因经历了几次起落,又由于经济政策和技术措施方面的某些偏颇与失误,导致烟叶质量下     

对我国烟草区域专业化生产的意见

我国烟草生产历史悠久,资源丰富,品种类型繁多,遍布全国各地。建国三十多年来,烟草生产发展很快,其中烤烟生产年总产量曾达两千多万担,占世界首位。晾晒烟种植时间最长,形成不少独具风格的名晾晒烟产地。香料烟、白肋烟先后从国外引进试种成功,都有不同程度的发展。黄花烟在少数民族地区有一定面积种植。所有这些烟草生产,对促进我国卷烟、雪茄烟、水烟等制品的生产,满足广大人民需要,扩大出口,增加财政收入,壮大集体经济都作出了很大贡献。     

我国烟草种质资源的种类与分布概况

种质资源是作物育种和人类生产的物质基础.笔者阐述了我国烟草种质资源的种类及其分布,详细介绍了野生烟、烤烟、晒晾烟、香料烟、白肋烟、雪茄烟和黄花烟的保存数量和种质特点,并对我国各类烟草种质资源的分布进行了比较和分析,旨在为我国烟草种质资源的进一步收集、保存及更好的利用提供理论和应用基础.     

我国部分烟草品种资源的品质状况

1986～1988年期间,对本所现有烟草品种资源中517份的烟叶内在品质,包括烟叶化学成分、主要烟气成分(焦油和烟碱)以及原烟香吃味等进行了系统的分析鉴定。筛选出质量好的材料26份,其中烤烟12份,晒烟10份,白肋烟2份,香料烟1份,雪茄烟1份;筛选出质量较好的材料41份,包括烤烟19份,晒烟17份,白肋烟4份,雪茄烟1份。经过3年的品质鉴定工作,摸清了517份品种资源的品质状况,并对这些资源作出了系统的科学评价,为今后我国烟草育种以及烟草生产提供了较为全面的科学依据。     

立足水情 强化管理——促进水资源可持续利用与经济社会可持续发展

水资源是人类赖以生存和发展的重要资源，是关系着自然界平衡发展的重要介质，是推动社会经济发展的战略性资源，可以说水资源的状况决定一个地区的经济发展。水资源能否可持续利用，关系着社会经济能否可持续发展。如今水危机问题已经成为了全球性的问题，一些地区的水资源紧缺性已经危及了地区的经济发展甚至人们的生存发展，在我国的一些地区水资源问题也十分的严峻，平泉即是其中之一，如何促进水资源可持续利用，保证经济社会可持续发展成为了区域发展的首要问题。     

区域水资源可持续利用评价指标体系探析

众所周知水资源是人类生存和发展不可缺少的重要资源,水资源的问题也受到了社会各界的关注和重视。近些年来水资源的问题日益突出,这些问题也严重影响了水资源作用的发挥,对水资源的开发和利用也产生了严重的影响。人们逐渐开始意识到水资源是有限的资源,如何实现区域水资源的可持续利用也成为了现阶段需要解决的重大问题。要想实现社会、经济和环境的协调发展,水资源的问题需要得到解决,而建立科学合理的可持续利用评价指标体系是实现水资源可持续发展的基本前提。文章首先对水资源的可持续利用进行简要的说明,其次说明建立评价指标体系的基本原则和分类,最后则是分析水资源可持续利用评价指标体系的建立。     

罗马尼亚培育烟草双抗PVY和TMV病毒品种的研究方法

罗马尼亚的土壤和气候条件适合种植香料烟、半香料烟、烤烟、白肋烟等类型烟草。罗马尼亚烟草生产上，马铃薯Y病毒(PVY)和烟草普通花叶病毒(TMV)可以造成严重的产量和质量损失，烟草生产上利用抗病品种是最有效的防病措施。     

武陵山区烤烟优质低耗配套技术开发

武陵山区是我国优质烟产地之一,烟草在本区经济开发中占有重要位置。本区虽有较丰富的土地和水热等自然资源,但区域经济和科学技术较落后,烟草品种杂,栽培和烘烤技术不当,限制了当地烟草生产的发展。为了促进本区烟草生产发展,从1986年冬开始,由中国农业科学院烟草研究所主持,与湖北省利川市烟草公司、成丰县烟草公司、湖南省龙山县烟草公司等单位组成协作组,共同开展“武陵山区烤烟优质低耗配套技术开发研究。本项研究是在已有研究成果的基础上,参考国内外先进技术,结合本区实际进行的。由于当地各级政府和有关业务部门的大力支持,经1986～1988年研究,     

烤烟抽样检查探讨

烤烟是卷烟工业的原料,原料质量的优劣直接影响到卷烟质量的稳定和提高。尤其是近10年来,吸烟与健康的呼声成为全世界关注的问题,这就对烟草生产和卷烟制品的质量提出了新的要求。为此,我国烤烟国家标     

烤烟抑芽剂试验研究初报

烤烟抑芽剂试验研究初报陈惠明，殷端（云南省烟草研究所）李龙梅（云南玉溪地区烟草栽培学校）刘玉安（中国农科院烟草研究所）烤烟进行封顶抹杈能提高烟叶产量和质量，提高烟碱含量，有利于烟碱和糖的协调，是提高烟叶品质的一项重要技术措施。目前生产上采用人工封顶抹...     

Oxidation of Fe(II) in rainwater

Photochemically produced Fe(II) is oxidized within hours under environmentally realistic conditions in rainwater. The diurnal variation between photochemical production and reoxidation of Fe(II) observed in our laboratory accurately mimics the behavior of ferrous iron observed in field studies where the highest concentrations of dissolved Fe(ll) occur in afternoon rain during the period of maximum sunlight intensity followed by gradually decreasing concentrations eventually returning to early morning pre-light values. The experimental work presented here, along with the results of kinetics studies done by others, suggests thatthe primary process responsible for the decline in photochemically produced Fe(II) concentrations is oxidation by hydrogen peroxide. This reaction is first order with respect to both the concentrations of Fe(II) and H2O2. The second-order rate constant determined for six different authentic rain samples varied over an order of magnitude and was always less than or equal to the rate constant determined for this reaction in simple acidic solutions. Oxidation of photochemically produced ferrous iron by other oxidants including molecular oxygen, ozone, hydroxyl radical, hydroperoxyl/superoxide radical, and hexavalent chromium were found to be insignificant under the conditions present in rainwater. This study shows that Fe(II) occurs as at least two different chemical species in rain; photochemically produced Fe(II) that is oxidized over time periods of hours, and a background Fe(II) that is protected against oxidation, perhaps by organic complexation, and is stable against oxidation for days. Because the rate of oxidation of photochemically produced Fe(II) does not increase with increasing rainwater pH, the speciation of this more labile form of Fe(II) is also not controlled by simple hydrolysis reactions.     

Photochemical production of Fe(II) in rainwater

Significant concentrations of Fe(II) were produced upon irradiation of authentic rainwater with simulated sunlight. The magnitude of photoproduction was dependent on initial Fe(II), Fe(III), and hydrogen ion concentrations, with more Fe(II) photoproduction when initial Fe(III) and H+ concentrations were high and initial Fe(II) concentrations were low. An equation was developed that accurately predicts photoproduction of Fe(II) in rainwater based on initial Fe speciation values and pH. The quantum yield of Fe(II) photochemical production in rain decreased dramatically with increasing wavelength and decreasing energy of incoming radiation with the average quantum yield at 265 nm approximately an order of magnitude greater than at 546 nm. Probable photochemical precursors of Fe(II) in authentic rain include iron(III) oxalate, iron(III) hydroxide, and an undefined Fe(III) complex. The wavelength-dependent Fe(II) production was modeled using the average Fe(II) efficiency spectrum, an average rainwater absorption spectrum, and the modeled actinic flux for temperate latitudes in both summer and winter. The response spectrum has the highest photoproduction of Fe(II) in summer and winter at 325 and 330 nm, respectively, with greater production in summer rain due to increased actinic flux and longer hours of irradiation.     

Chromium speciation in rainwater: temporal variability and atmospheric deposition

The concentrations of the various chromium species were determined in 89 rainwater samples collected in Wilmington, NC, from October 1, 1999, to December 31, 2001. Volume-weighted annual average concentrations of Cr(total), particulate Cr, Cr(III)(aq), and Cr(VI)(aq) were 4.6, 2.2, 0.8, and 1.2 nM, respectively. There was distinct seasonal and diurnal variability in the concentrations of the various chromium species. Chromium emissions to the global atmosphere by both natural and anthropogenic sources are estimated to be 2.2 x 10(9) mol/yr. Using our rainwater concentration data along with other published rainwater Cr concentrations and an estimate for total global annual rain, the total global flux of chromium removed from the atmosphere via wet deposition is 2.1 x 10(9) mol/yr. This represents complete removal of Cr and indicates that essentially all chromium released into the global atmosphere is removed via rain. About half this chromium is dissolved with roughly equal concentrations of toxic Cr(VI) and relatively harmless Cr(III) species.     

Redox speciation of copper in rainwater: temporal variability and atmospheric deposition

Copper speciation was determined in 68 rainwater samples collected in Wilmington, NC, from August 25, 2000, to September 24, 2002. Volume-weighted average concentrations of Cu(total), dissolved Cu(II), and dissolved Cu(I) were 5.3, 3.2, and 1.4 nM, respectively, with a significantly higher ratio of Cu(II)/Cu(I) in summer relative to winter events. The concentrations of all Cu species were higher in storms of continental origin relative to marine-dominated events, suggesting anthropogenic and/or terrestrial sources are important contributors of Cu in precipitation. Concentrations of strong Cu-complexing ligands were consistently lower than dissolved Cu concentrations, indicating a significant portion, but not all, of the dissolved Cu in rainwater is strongly complexed. A portion of these ligands, in addition to the sulfite and chloride in precipitation, may be Cu(I)-complexing ligands, which may explain the resistance of Cu(I) against oxidation in rainwater. Using our rainwater concentration data along with other published rainwater Cu concentrations and an estimate for total global annual rain, the total global flux of Cu removed from the atmosphere via wet deposition is 150 x 106 kg yr(-1). This represents complete removal of the estimated Cu input into the troposphere and indicates essentially all Cu released into the global atmosphere is removed by rain.     

Risk of gastrointestinal illness associated with the consumption of rainwater: a systematic review

The collection of rainwater for human consumption is a practice well established in many parts of the world. Much of the research to date regarding this inexpensive and sustainable source has focused on its microbiological or chemical quality and there have been no reviews of epidemiological evidence regarding actual health risks associated with rainwater consumption. Electronic bibliographic databases were searched for epidemiological studies that attempted to quantify the risk of gastrointestinal disease linked to the consumption of harvested rainwater. Online databases were searched from the oldest date up to January 2011. Both observational and experimental studies were included. In addition, reference sections of key articles were searched and authors of previous studies were contacted where appropriate. Studies were assessed for relevance independently and in duplicate. Searches returned a total of 764 articles, 13 met inclusion criteria, 5 of these were outbreak reports, and 9 were studies of other design types. Pooled subgroup analysis suggests that rainwater is associated with reduced risk of illness compared to unimproved supplies (relative risk 0.57 95% CI 0.42, 0.77). There was no significant difference in risk in the pooled analysis of studies that compared rainwater to improved water supplies (relative risk 0.82 95% CI 0.38, 1.73). However, there was heterogeneity with one study showing an excess risk of campylobacteriosis. Classification of outbreak reports determined that 4 reports were "strongly associated with rainwater" while 1 report was "probably associated with rainwater". We conclude that the evidence suggests that rainwater is safer than water from unimproved water supplies. Where feasible rainwater harvesting should be encouraged as a step toward achieving millennium development targets.