6植物生理学讲义.pptx

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1、本章重点和难点：一、植物体内有机物质的次级代谢；二、植物次级产物的合成途径。第1页/共31页第一节 各类有机物代谢的相互关系蔗糖、淀粉等有机物来源于光合作用，通过呼吸作用分解产生各种中间产物。C3循环、EMP、TCA和PPP筑成了有机物代谢的主干。糖和脂肪、蛋白质、核酸之间都可以相互转变。丙酮酸、乙酰COA、-酮戊二酸、草酰乙酸等中间产物起着枢纽作用。第2页/共31页Plant SecondaryMetabolismPlant metabolic pathways are linkedThese linkages include several key carbon-based primary

2、 metabolites(初级代谢物)As plants evolved,they found new(secondary)ways to use metabolitesRandom mutations lead to a variety of specialized plant secondary compounds第3页/共31页葡萄糖多糖淀粉、纤维素半纤维素戊糖(Ru5P)核苷酸核酸DHAPPGAldPEP丙酮酸乙酰C CO OA A-酮戊二酸C3途径CO2草酰乙酸TCA丙二酰C CO OA A甘油+脂肪酸脂肪酚类、萜类化合物丙氨酸等酒精乳酸天冬氨酸族烟碱AMP、GMP谷氨酸族蛋白质卟啉

3、(chl,Cyt)PPP第4页/共31页第二节 植物体内的次级产物次级产物：是植物体内由糖类等有机物代谢衍生而来的物质。贮存在液泡或细胞壁中，是代谢的中产物，不再参与代谢。次级产物具有重要作用：是植物生命活动所必需的，如IAA、GA；叶绿素和类葫萝卜素及花色素；木质素等，是植物组织色、香、味的主要构成成分，是药业或工业的重要原料。植物的次级产物可分3类：酚类、萜类、含氮次级化合物第5页/共31页第6页/共31页萜类的种类：萜类是以异戊二烯(isoprene)为单位组成的，按其数目，可分为:单萜(monoterpene)、倍半萜(sesquiterpene)、双萜(diterpene)、三萜(t

4、riterpene)、四萜(tetraterpene)、多萜(polyterpene)。CH3 头 CH2=C CH=CH2 尾一、萜 类 terpene第7页/共31页Terpenoids:The largest groupFormed from 5-C subunits(isoprene)synthesizedfrom G-3-P,pyruvate,and acetyl-CoACompounds have from 10 to 40 carbonsSome terpenoids have functions in growth anddevelopment Plant hormones(g

5、ibberellins,abscisic acid)Accessory pigments in photosynthesisMost terpenoids act as herbivory deterrents andare a prime example of a“biochemical arms race”第8页/共31页Monoterpenes(C-10)Pyrethroid insecticides拟除虫菊脂Conifer resins松脂Plant-plant defensive Communication防御沟通 Deter pest Attract pest predatorsE

6、ssential oils（Essential oils are often stored in surface glands表面腺细胞）第9页/共31页Sesquiterpenes(C-15)Herbivory deterrents威慑草食动物(generalized)BitternessExamples include sagebrush山艾树 and sunflower向日葵第10页/共31页Diterpenes(C-20)Toxins and irritants 毒与刺激(generalized)Resins from some trees to seal herbivore indu

7、ced wounds 松脂封闭取食伤口Human use has adapted these compounds to anti-cancer drugs(Taxol紫杉醇 from Pacific yew紫杉)第11页/共31页Tri-terpenes(C-30)More specialized toxinsSteroid in structure结构类固醇Examples Cardenolides vertebrate heart toxins脊椎动物心脏毒素 Saponins 皂角苷 detergent like structure第12页/共31页植物体内重要的萜类物质：挥发油：是单萜

8、和倍半萜，樟树茎、柑橘果皮、薄荷植株等 棉 酚：倍半萜，是重要的抗虫侵袭、抗真菌和细菌的物质 固 醇：三萜的衍生物，质膜成分，植物蜕皮激素的成分 类胡萝卜素：四萜衍生物，有叶黄素、胡萝卜素番茄红素等，橡 胶：多萜化合物一、萜 类 terpene第13页/共31页二、酚 类phenol种类：按芳香族环上带有的碳原子数可分为 简单酚类、木质素、类黄酮类、鞣质类和其它酚类主要的酚类化合物有：简单酚类：桂皮酸、咖啡酸、香豆素、水扬酸 木质素：没食子酸、木质素、类黄酮类：花色素苷、黄酮、黄酮醇、异黄酮 鞣质类：缩合鞣质和可水解鞣质第14页/共31页Phenolic compoundsCommon ele

9、ment is a phenolic groupDerived from amino acids,principally phenylalanine（苯丙氨酸）第15页/共31页Examples of phenolic compounds and their rolesPhenylpropanoids（苯丙酸类化合物），具有苯环-C3的基本骨架。Allelopathic compounds inhibit plant growth（A为咖啡酸、阿魏酸）第16页/共31页Examples of phenolic compoundsand their rolesFuranocoumarins 呋喃

10、香豆素类(celery芹菜,parsnip欧洲防风草,and parsley欧芹)Toxicity to insect herbivores（草食昆虫毒素）UV-activated toxins：UVA（320-400nm）激发为高能电子态，插入DNA中，与胞嘧啶和胸腺嘧啶结合，阻断DNA转录和修复，导致细胞死亡。第17页/共31页Examples of phenolic compoundsand their rolesBenzoic acid derivatives（安息香酸派生物）Systemic resistance to pathogens（病原物系统抗性）第18页/共31页Plant

11、“immune systems”Plant-wide response to a local infectionMay involve both toxic compounds like oxygen radicalsCan produce a memory response第19页/共31页Plant“immune systems”Phytoalexins（植物抗毒素）are a primary player in plant immune responsePhytoalexins can be antimicrobial terpenoids or phenolics（抗菌的萜或酚类）Sy

12、nthesized in response to infection or attack第20页/共31页Jasmonic acid Stress anddefense hormoneProduced in response to a signal transduction pathwayInduces synthesis of other defensive compoundsActivates responses at the gene level第21页/共31页Examples of phenolic compoundsand their rolesLignin木质素 Reinforc

13、ing molecule(esp.in woody tissue)组成物质 Decreases palatabilityTannins丹宁 Flavor deterrent威慑味道，如涩味 Tea,blackberry,grape,apple Mode of action is via protein binding蛋白鞣质结合第22页/共31页Examples of phenolic compoundsand their rolesFlavonoids Anthocyanins（花青素）:Pigmentation(pollinator attractant)Flavones and Flav

14、onols（黄酮和黄酮醇）:UV protection and beeAttractant（引诱剂）：(nectar guides花蜜引导)Isoflavones（异黄酮）:Antimicrobial（抗菌）,antiestrogenic（抗雌激素）第23页/共31页三、含氮次级化合物l生物碱(alkaloid)：核酸的组分，亦是维生素B1、叶酸和生物素的组 分，它对动物有毒，可起防御敌害作用；是重要药物的 有效成分，如奎宁、吗啡、利血平、阿托品等。l含氰苷(cyanogenic glycoside)：豆类、禾谷类和玫瑰中较多，本无毒，但释放HCN。l芥子油苷(mustard oil glyc

15、oside)：十字花科，本无毒，但水解后产生有毒物质。l非蛋白氨基酸(nonprotein amino acid)：不构成蛋白质的氨基酸，有毒性，有的阻止 蛋白氨基酸的合成或吸收。第24页/共31页Nitrogen-Containing Compounds:Only chemical similarity is the presence of nitrogen somewhere in the moleculeWell studied because of their toxicity to animals and their medicinal valuePerhaps the most e

16、asily-recognizable group of secondary compounds in plants第25页/共31页Examples of N-containingcompounds and their rolesAlkaloids A large group of compounds found in 20%ofall plant species All contain a heterocyclic ring杂环(i.e.,a ring formed from carbons and one nitrogen)Best known for their pharmacologi

17、cal effect on animals(动物药理学的效应)第26页/共31页Examples of alkaloids第27页/共31页Examples of N-containingcompounds and their rolesCyanogenic glycosides含氰苷，存在与叶表皮的液泡中 A large group of compounds found in thousands of plant species Stored in leaves(cherry樱桃,Johnson grass),seeds(apple,peach),or roots(cassava木薯)Enz

18、ymatic release of cyanide gas following herbivory第28页/共31页Examples of N-containingcompounds and their rolesGlucosinolates(mustard oil glycosides)芥子油苷：十字花科，本无毒，但水解后产生有毒物质。Principally found in plants from the Brassicaceae Enzymatic release following herbivory Volatile defensive compounds 挥发性防御物(toxins,deterrents)Can also serve as attractants引诱剂第29页/共31页Examples of N-containingcompounds and their rolesl非蛋白氨基酸：不构成蛋白质的氨基酸，有毒性，有的阻止 蛋白氨基酸的合成或吸收。Non-protein amino acids Interfere with herbivore protein synthesis Replace normal amino acids to create nonfunctional proteins第30页/共31页谢谢大家观赏！第31页/共31页