21世纪植物化学生态学前沿领域

植物和其它有机体通过次生物质为媒介的化学作用关系近年引入注目,其中植物的诱导化学防御,植物的化学通讯,植物次生物质和进化的关系,植物与人类的化学关系和海洋植物化学生态学是21世纪植物化学生态学值得关注的前沿领域。植物化学生态学前沿领域的进展将为实现21世纪的持续,发展是在生态安全条件下提高农业产量并达到对病虫草害的有效控制方面具有重要意义。     

我国资源植物化学与天然产物化学基础研究的现状与发展

本文从生物活性成分的筛选与分离、植物次生代谢产物生物合成及其分子调控、环境因子对植物次生代谢产物合成和积累的影响、植物体内生菌与植物次生代谢产物的关系等方面介绍了我国资源植物化学与天然产物化学领域基础研究的现状与发展。     

植物次生物质对于植物生存的重要作用

植物次生物质在植物生存中抵御动物和微生物的侵害,参与同其他植物的生存竞争以及进行植物间化学通讯等方面具有重要的作用。植物次生物质的产生是植物化学保护的必然结果。简要介绍植物次生物质的合成途径。     

生物的化学通讯

生物个体（同种或异种）相互之间的有着化学信息联系,昆虫,特别是社会性昆虫化学通讯是其沟通信息的主要方式,我们关于化学通讯的知识大多来自于对昆虫信息素的研究,近来的研究已揭示在植物和植物以及植物和动物之间也存在着化学信息交流。     

植物化学分类学研究进展

植物化学分类学(Plant Chemotaxonomy)是从分子水平上研究植物类群及其亲缘关系,探讨植物演化规律的一门学科。近年来,由于植物化学成分分离、分析方法的改进和技术设备的革新,更多类群的化学成分得到广泛深入的研究,从而为化学分类学提供了许多新证据,同时,由于经典分类学家观念的更新,吸取了相关学科的成果,对传统的分类方法和     

干热河谷植物化学计量特征与生物量之间的关系

了解植物化学计量学特征对生物量变化的响应机制对预测全球变化下植物生产力以及生态系统功能具有重要意义。为了了解干热河谷地区植物化学计量学塑性变化与植物生物量变化的关系, 该研究以当地的典型燥红土为基质, 观察水分、养分以及二者的交互作用对6种植物的生长的促进作用, 并分析这种作用与植物化学计量学特征变化的关系。研究结果显示: 水分、养分、物种及其二元交互作用对植物生长具有显著的作用。养分添加处理增加了32.55%的生物量, 高频次水分处理增加了31.35%的生物量, 水分与养分复合处理下生物量增加了110.60%。植物化学计量学特征的变化与植物生物量对处理的响应具有显著相关性。其中, 植物总体K:Ca、K:Mg、K:Mn、K:Zn、Mg:Mn的变化与植物生物量的变化呈正相关关系, 表明水分和养分处理对植物生长的促进作用影响了植物养分的平衡, 主要的变化趋势是高含量元素与低含量元素的计量比随着生物量的增加而不断增加。此外, 相对于植物生物量变化, 处理类型和物种因素对多数化学计量学特征变化无显著影响, 表明水分和养分处理对化学计量学的影响具有相同的驱动机制, 即通过生物量变化最终影响化学计量学变化。植物生物量对水分和养分的响应可对植物化学计量学特征以及生态系统功能产生深远的影响。     

紫杉烷类化合物研究进展

综述了近年来紫杉烷类在植物化学和药物化学方面的研究进展。着重介绍新的紫杉烷类天然化学成分的分离及其半合成衍生物。     

记全国植物资源学和植物化学学术讨论会

在中国植物学会直接领导下,由浙江农业大学和浙江省植物学会承办,中国植物学会植物资源学专业委员会和植物化学专业委员会于1995年10月22—26日在杭州召开了“全国植物资源学和植物化学学术讨论会”。 参加会议代表有97人。他们分别来自北京、上海、江苏、浙江、广东、福建、云南、贵州、四川、辽宁、吉林、黑龙江、安徽、江西、青海、河南、河北和山东等省、市。大会收到有关植物资源学和植物化学方面论文摘要92篇。大会还特邀著名专家作专题报告,例如孙汉董的“植物化学与新药开发”、杨峻山的“杜仲研究的现状与展望”和陈迪华的“天然多酚成分研究进展”等。     

植物生态化学计量内稳性特征

化学计量内稳性是生态化学计量学研究的核心概念之一,是指生物在面对外界变化的时候保持自身化学组成相对稳定的能力,其反映了生物对周围环境变化作出的生理和生化响应与适应。通过研究植物生态化学计量内稳性,有助于深入了解植物对环境的适应策略和生态适应性,以及植物化学计量内稳性与生态系统功能的关系,但目前关于植物生态化学计量内稳性的研究较少。已有的研究结果表明:不同物种或功能群由于其生长策略不同而具有不同的生态化学计量内稳性特征;同一物种的不同器官、不同生长阶段以及不同元素的内稳性存在较大的差异。该文对植物生态化学计量内稳性概念、内稳性指数的测算方法,不同植物物种或功能群、不同器官、不同生长阶段内稳性特征,以及植物内稳性与生态系统结构、功能和稳定性的关系等方面进行了综述,并结合现已开展的工作,对有待进一步拓展的相关植物生态化学计量内稳性研究领域进行了展望,以期为促进国内相关研究工作的开展提供参考。     

植物化学提取物对大肠癌作用及其机制的研究进展

大肠癌(colorectal cancer)是胃肠道疾病中常见的恶性肿瘤,其发病率及死亡率均较高。近年来,植物化学提取物指采用适当的溶剂或方法,以植物(整体或部分)为原料提取或加工后所获取的物质,作为肿瘤化学预防治疗的重要组成部分对大肠癌的作用已受到研究者们的广泛关注。研究发现,不同植物化学提取物包括植物多酚类、多肽类、生物碱、皂苷类、多糖类及维生素类等均具有抗大肠癌的作用,作用机制主要与抑制肿瘤细胞增殖、促进肿瘤细胞凋亡、阻断细胞周期、抑制肿瘤血管形成、诱导大肠癌细胞自噬、抑制大肠癌细胞迁移等途径密切相关。本文主要就大肠癌的发生机制、植物化学提取物的种类及其预防和治疗大肠癌的体内外最新研究进展进行了综述,旨在为大肠癌的临床防治提供更多的理论依据。     

Phytoalexins from Brassicaceae: News from the front

The chemical structures, syntheses, metabolism and biological activities of the cruciferous phytoalexins discovered to date, with particular focus on the latest results dealing with their biosynthesis and detoxification are reviewed.     

Inducible phytoalexins in juvenile soybean genotypes predict soybean looper resistance in the fully developed plants

The hypocotyl of different soybean genotypes was tested for its inducible phytoalexin (i.e. glyceollin or coumestrol) accumulation and its inducible soybean looper resistance in response to chemical elicitation. A very highly insect-resistant soybean genotype (PI 227687) produced significantly more phytoalexins than a relatively insect-susceptible one (Davis) in response to the same chemical elicitation. The resultant standardized hypocotyl assay allowed quick categorization of unknown soybean genotypes regarding the level of insect resistance in the fully developed plants. Glyceollin was a better indicator of inducible resistance than coumestrol. Elicitor concentration influenced the amount of glyceollin and coumestrol accumulated. Younger seedlings (4-5 d old) responded stronger to chemical elicitation than did older ones (7-10 d old). The elicited accumulation of glyceollin showed a temporal pattern that peaked at 72 h. Accumulation of coumestrol showed a gradual increase. Elicitation of phytoalexins in juvenile soybean plants by sulfhydryl-binding reagents was found to be useful for the prediction of genotypic differences in the level of insect resistance in the fully developed plants.     

植物抗病性物质的研究进展

植物与病原菌相互作用后在植物体内会产生抗性物质。植物的抗病性物质包括两大类：植物固有的抗菌物质和植物保卫素。本文就近年来对植物抗病性物质的化学组成、生物合成、代谢途径方面的研究进行了综述。     

植物抗病性物质的研究进展

植物与病原菌相互作用后在植物体内会产生抗性物质。植物的抗病性物质包括两大类 :植物固有的抗菌物质和植物保卫素。本文就近年来对植物抗病性物质的化学组成、生物合成、代谢途径方面的研究进行了综述。     

Synthesis of Chiral NADH Model Compounds Containing a Sulfur Atom and Their Asymmetric Reduction

Oryzalexins A, B and C were isolated as a group of novel phytoalexins from rice (Oryza sativa) blast leaves infected with Pyricularia oryzae. The basis of the structures of Oryzalexins A, B and C was laid by spectroscopic methods and their inhibitory activities against spore germination and germ tube growth of P. oryzae were assayed.

Oryzalexins A, B and C, isolated from rice leaves infected with P. oryzae as a group of novel phytoalexins, were confirmed to be (+)-sandaracopimaradiene derivatives by chemical and spectroscopic studies, i.e. A: 3-oxy-7-oxo- (I); B: 3-oxo-7-oxy- (II) and C: 3,7-dioxo-(+)-sandaracopimaradiene (III).     

Phytoalexins of woody plants

Summary Phytoalexins accumulated in selected woody plants in response to microbial attack or stress are reviewed and listed with respect to their chemical structure and probable biogenetic origin. The host-pathogen systems from which they have been isolated are described. The review also considers the antimicrobial activity of the phytoalexins to the causal pathogens and other microorganisms.     

Detoxification of cruciferous phytoalexins in Botrytis cinerea: spontaneous dimerization of a camalexin metabolite

Phytopathogenic fungi are able to overcome plant chemical defenses through detoxification reactions that are enzyme mediated. As a result of such detoxifications, the plant is quickly depleted of its most important antifungal metabolites and can succumb to pathogen attack. Understanding and predicting such detoxification pathways utilized by phytopathogenic fungi could lead to approaches to control plant pathogens. Towards this end, the inhibitory activities and metabolism of the cruciferous phytoalexins camalexin, brassinin, cyclobrassinin, and brassilexin by the phytopathogenic fungus Botrytis cinerea Pers. (teleomorph: Botryotinia fuckeliana) was investigated. Brassilexin was the most antifungal of the phytoalexins, followed by camalexin, cyclobrassinin and brassinin. Although B. cinerea is a species phylogenetically related to the phytopathogenic fungus Sclerotinia sclerotiorum (Lib) de Bary, contrary to S. sclerotiorum, detoxification of strongly antifungal phytoalexins occurred via either oxidative degradation or hydrolysis but not through glucosylation, suggesting that glucosyl transferases are not involved. A strongly antifungal bisindolylthiadiazole that B. cinerea could not detoxify was discovered, which resulted from spontaneous oxidative dimerization of 3-indolethiocarboxamide, a camalexin detoxification product.     

Recent advances regarding diterpene cyclase genes in higher plants and fungi

Cyclic diterpenoids are commonly biosynthesized from geranylgeranyl diphosphate (GGDP) through the formation of carbon skeletons by specific cyclases and subsequent chemical modifications, such as oxidation, reduction, methylation, and glucosidation. A variety of diterpenoids are produced in higher plants and fungi. Rice produces four classes of diterpene phytoalexins, phytocassanes A to E, oryzalexins A to F, oryzalexin S, and momilactones A and B. The six diterpene cyclase genes involved in the biosynthesis of these phytoalexins were identified and characterized. Fusicoccin A was produced by the phytopathogenic Phomopsis amygdali and served as a plant H(+)-ATPase activator. A PaFS, encoding a fungal diterpene synthase responsible for fusicoccin biosynthesis, was isolated. The PaFS is an unusual chimeric diterpene synthase that possesses not only terpene cyclase activity (the formation of fusicoccadiene, a biosynthetic precursor of fusicoccin A), but also prenyltransferase activity (the formation of GGDP). Thus, we identified a unique multifunctional diterpene synthase family in fungi.     

Selective toxicity of wyerone and other phytoalexins to gram-positive bacteria

The antibacterial activities of isoflavonoid (kievitone and phaseollin), flavonoid (hydroxyflavans), furanoacetylenic (wyerone), and sesquiterpenoid (capsidiol and rishitin), phytoalexins against eight Gram-negative and six Gram-positive bacteria were examined using the paper-disc antibiotic assay method. With the exception of capsidiol, which was inactive at the highest concentration tested (200,μg/disc) all of the phytoalexins were selectively toxic towards Gram-positive species. Wyerone and kievitone were generally more toxic than other phytoalexins; rishitin was the least active inhibitor.     

Rooting cofactor activity of plant phytoalexins

The pterocarpinoid phytoalexins, glyceollin, pisatin, and phaseollin, stimulated adventitious root formation in a mung bean rooting bioassay only in the presence of indoleacetic acid (rooting cofactor activity). Relatively low (5 to 50 micrograms per milliliter) concentrations of the phytoalexins were effective. The phytoalexins also increased the numbers of root primordia formed, therefore suggesting that they interacted with an early process in root formation.