【作者】 戴进用；

【导师】 朱朝华；

【作者基本信息】 海南大学 ， 农药学， 2010， 硕士

【摘要】 小飞蓬(Conyza canadensis),是菊科白酒草属的一种外来入侵植物,是严重为害的区域性杂草之一。小飞蓬的化感作用是其能够成功入侵的重要机制之一,目前这方面的工作还仍处于初步阶段。本文主要测定了小飞蓬对几种不同科属的受体植物的化感效应；测定经小飞蓬水浸液处理的萝卜幼苗体内生理生化指标的变化；运用分步萃取和柱层析技术,并结合生物测定方法,初步分析小飞蓬水浸液中的化感物质。主要的结果如下：1.小飞蓬水浸液具有较强的化感作用,且具有浓度效应,随着浓度的增大化感活性表现逐渐增强。小飞蓬水浸液能显著抑制受体植物种子的萌发,如0.20g／mL小飞蓬茎叶水浸液对苋菜种子的萌发率和萌发指数的RI值分别为-0.822和-0.892。另外,小飞蓬水浸液对受体植物幼苗的生长表现出了明显的抑制作用。当根部水浸液的浓度为0.10g/mL时,柱花草和苋菜这2种受体植物幼苗的根都受到了极显著地抑制,其RI值分别为-0.622和-0.667。2.各项指标的综合分析结果表明,小飞蓬植株不同部位的化感作用大小并不存在差异。但小飞蓬对不同植物所表现的化感作用大小差异显著,其中,苋菜受到的化感作用最强,柱花草次之。3.研究得出,相对高浓度的水浸液显著抑制了萝卜幼苗体内SOD和POD的活性,以致其叶绿素含量和可溶性蛋白质含量减少,抑制了茎的生长,而且增大了其根部MDA的含量,抑制了根的生长,最终导致植株鲜重的减小。但是相对低浓度的水浸液处理后,茎叶内SOD和POD活性以及叶绿素含量明显增大,可溶性蛋白质含量增大,从而茎长变长,最终植株鲜重增加了,但这后3项指标的增加程度并不明显。4.小飞蓬水浸液中有大量的能溶解于乙酸乙酯且具有化感活性的组分。在乙酸乙酯相萃取物的处理液中,萝卜种子的萌发率和萌发指数以及其幼苗根长受到的抑制率分别为98.37%、98.87%和93.09%。乙酸乙酯相萃取物和石油醚相萃取物的抑菌活性较高。乙酸乙酯相萃取物对香蕉炭疽菌的EC50仅为0.610mg/mL。5.柱层析分离小飞蓬乙酸乙酯相萃取物,得到了18组馏分,其中以Fr10-14和Fr19-30这2组馏分的生物活性最强,1.0mg/mL的处理液对柱花草种子萌发的抑制率分别达到了69.87%和65.81%,0.5mg/mL的处理液对香蕉炭疽菌生长的抑制率就分别达到了94.24%和94.60%。通过GC-MS分析得出,Fr19-30中含有的物质中,许多组分具有化感活性,如酮类和酯类等,其中7,7-二甲基-4-乙氧基亚甲基-双环[3,2,0]-2-庚烯-6-酮的含量最高,达到了37.70%。本论文对小飞蓬水浸液的化感作用进行了研究,可为系统评价小飞蓬化感作用特点和初步探究小飞蓬化感作用的机制提供理论基础,为进一步研究小飞蓬的化感物质奠定了基础更多还原

【Abstract】 Conyza canadensis (L.)Cronq.(C. canadensis),an. invasive plant of genus Conyza, Compositae,is one of the regional weeds which is serious harm to.The allelopathy of C. canadensis is the important mechanisms of it successful invasion,its research is still in preliminary stages.In this paper, determined the allelopathic effect of the aqueous extracts from C. canadensis on several receptor plants of different families and genus;determined the changes in physiological and biochemical indexes of Raphanus sativus’s seeding which was dealed with the aqueous extracts;through step extraction method and column chromatography,combined with biometrics,preliminarily analysed the allelochemical in the aqueous extracts from C. canadensis.The main results were as follows:1.The aqueous extracts from C. canadensis had strong allelopathic effects and concentration effect,with the increaseding of its concentration,the allelopathic activity is also increaseding gradually.The aqueous extracts from C. canadensis could inhibit the germination of receptor plants’seeds,such the RI values of 0.20g/mL aqueous extracts from the Stems and leaves of C. canadensis on the germination rate and germination index of Acalypha hainanensis’s seed were-0.822 and-0.892.In addition,the aqueous extracts from C. canadensis on the growth of receptor plants’seedling showed significant inhibition. When the concentration of the aqueous extracts from the roots of C. canadensis was 0.10g/mL,the roots of tylosanthes guianensias and Amaranthus mangostanus these tow receptor plants’seedlings have been significantly inhibited,the RI values were-0.622 and-0.667.2.Comprehensived analysis of the indicators show that,the difference between the allelopathy of different parts of C. canadensis’plant did not exist.However,the allelopathy of C. canadensis on different plants shown significant differences in size,which allelopathic effects on Amaranthus mangostanus were the strongest,followed by Stylosanthes guianensias.3.Researched results showed that,relative high concentrations of aqueous extracts inhibited the activity of SOD and POD of Raphanus sativus’seedlings,chlorophyll content and soluble protein content decreased,inhibited the growth of stems,increased MDA,and inhibit the growth of root,ultimately leading to reduced plant fresh weight.But after the treatment of the relatively low concentration, the activity of SOD,POD and chlorophyll content in leaves of Raphanus sativus’ seedlings significantly increased,soluble protein content increased,so the stem became longer,the final plant fresh weight increased,but the other three indicators increase in the degree is not obvious.4.There were a large number of components can be dissolved in ethyl acetate which have allelopathic activity in the aqueous extracts from C. canadensis.In. the treatment solution of ethyl acetate extract,the inhibition rates of the germination rate and germination index of Raphanus sativus’ seed and the root length of its seedlings were 98.37%,98.87% and 93.09%.Ethyl acetate extract and petroleum ether extract has high antibacterial activity,and the EC50 of ethyl acetate extract on Colletotrichum musae only is 0.6103mg/mL.5.Used column chromatography to separate ethyl acetate extracts of C. canadensis,obtained 18 sets of fractions,and the biological activity of Fr10-14 and Fr 19-30 these two groups is the strongest,the inhibition rate of 1.0mg/mL solution on the germination of Stylosanthes guianensias’Seed reached 69.87%and 65.81%,and the inhibition rate of 0.5mg/mL solution on the growth of Colletotrichum musae reached 94.24% and 94.60%.Obtained by GC-MS analysis,some of the substances in Fr19-30 contains have allelopathic activity,such as ketones and esters,and the content of 7,7-DIMETHYL-4-[(Z)-ETHOXYMETHYLIDENE]-BICYCLO[3.2.0]HEPT-2-EN-6-ONE is the highest in it, reaching 37.70%.Study on allelopathy of the aqueous extracts from C. canadensis would supply theory foundations for systematic review to the characteristics of C. canadensis’allelopathy and inqriry preliminarily the mechanisms of C. canadensis’allelopathy and establish basis for studying the allelochemical of C. canadensis in futher.更多还原