植物的光合作用

光合作用是绿色植物在日光下吸收碳的过程。碳是有机物质的主要成分,约占生物体内干重的一半。植物能利用许多简单的无机化合物来大量合成这些有机物质,而这些简单的化合物是从周围环境里获得的。碳来自空气中的或溶解在水中的二氧化碳;还原二氧化碳所需用的氢来源於水,合成反应所需的能量则来自叶绿素所吸收的日光。这些原料广布各处,因此绿色植物就成为世界生物中的一大类。千万年来,它在地球上储存了对它本身生活所必需及对所有其他生物所必需的有机物质和化学能     

植物生长物质

本文简要介绍植物生长物质的化学结构对活性的影响，植物生长调节剂在农作物上的应用以及生长调节剂的生产方法。     

植物中的元素

总结了作者近几年的实验研究工作，认为在一定区域内，每种植物都有特定的元素含量，并提出了植物元素谱和无机元素植物分类学的概念。     

土壤的植物修复与超积累植物研究

被污染土壤的植物修复将是未来更好与更廉价的修复技术,所以近年来对植物修复与超积累植物的研究兴趣日益增加。本文简要介绍了近期的发展趋势。目前研究的重点包括根际土壤微环境中的复杂反应与吸收过程,金属从土壤向植物根以及从植物根向叶的传输过程,金属在超积累植物中的定位与螯合作用等等。这是分析化学与环境科学及植物科学交叉研究的新领域,充满挑战。     

植物内生真菌抗植物病原真菌活性物质的研究

植物内生真菌的代谢产物中存在一系列具有多样性结构的抗植物病原真菌的活性化合物(AFC)。本文以化合物结构为线索,对植物内生真菌所产生的具有抗植物病原真菌活性的生物碱、肽类、萜类、甾体、醌、有机酸、酯类等化合物的结构,对病原菌的抑制效果及其寄主植物等几方面进行了总结。从3个方面简单介绍了农用抗生素的作用机制,即作用于真菌细胞壁、细胞膜,以及抑制真菌蛋白质的生物合成。最后对AFC作为新型农用抗生素来源的前景进行了展望,其具有作为先导化合物,开发高效、低毒、无公害农用抗生素的巨大潜力。     

植物绿原酸的研究进展

介绍了绿原酸的性质、作用、提取、应用,揭示了绿原酸具有潜在的、广阔的应用前景。     

由植物制造燃料油

据美国国立可再生能源实验室E.Jarvis等报告,在一般情况下藻类把二氧化碳和水转化为糖和蛋白质;但在缺氮气时,则主要产生油。他们通过克隆一个海藻基因,引、入乙酞辅酶A梭化酶密码,可以在干旱废地上的盐水池塘里养殖藻类,将发电厂废气的二氧化碳通入水中,如此可获得燃料油。     

微量元素与植物生长

在上世纪60年代,湖北浠水、靳春两县出现了甘蓝型油菜大面积发生只开花而不结果实的现象,愁坏了当地的农民们。后来经科研人员多次研究,发现原来是缺乏微量元素硼所致,施用硼肥以后这种“花而不实”的现象就再没发生。农民兄弟高兴地称“硼”是他们的救星。由这个例子可见微量元素不但对人体起关键作用,同样在植物中也起着举足轻重的作用。把植物微量元素营养元素应用于农业系统始于上世纪20-30年代,微量元素肥料是第二次世界大战以后发展起来的新型肥料,我国是在50年代开始进行微肥试验研究和应用的。在我国北方潮土等一大批土壤都存在土壤…     

植物甾醇女士访谈录

通过采访植物甾醇女士,了解植物甾醇家族的成员、基本性质、生理功能等。揭示了其降低胆固醇、减肥、美容功能的基本原理,了解了抗癌机理,介绍了植物甾醇在食物中的分布、人体吸收困难的原因及对策,为人类健康生活提出膳食建议。     

土壤氟与植物

氟是人体必需微量元素,其丰缺与人体健康息息相关。土壤在地理环境中的特殊地位决定着土壤氟对生态环境的特殊意义。土壤氟(特别是土壤水溶性氟)与植物体的氟含量密切相关,从而也与人体健康密切相关。不同植物对氟的富集程度不同,蔬菜(特别是叶菜)对土壤氟的富集程度很高,是造成地氟病的重要因素。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.