《烟草栽培理》-翻译作业-烟草11级-杜桂标.docVIP

《烟草栽培生理》作业 任课教师：杨飞 班级：烟草2011级2班 姓名： 学号：201131 文献来源: The Only African Wild Tobacco, Nicotiana africana :Alkaloid Content and the Effect of Herbivory （在NCBI上找不到，不过查了影响因子PLOS3.534的影响因子） The Only African Wild Tobacco, Nicotiana africana :Alkaloid Content and the Effect of Herbivory 唯一的非洲野生烟草，N.AFRICANA：生物碱含量和草食动物对其的影响 Abstract Herbivory in some Nicotiana species is known to induce alkaloid production. This study examined herbivore-induced defenses in the nornicotine-rich African tobacco N. africana, the only Nicotiana species indigenous to Africa. We tested the predictions that: 1) N. africana will have high constitutive levels of leaf, flower and nectar alkaloids; 2) leaf herbivory by the African bollworm Helicoverpa armigera will induce increased alkaloid levels in leaves, flowers and nectar; and 3) increased alkaloid concentrations in herbivore-damaged plants will negatively affect larval growth. We grew N. africana in large pots in a greenhouse and exposed flowering plants to densities of one, three and six fourth-instar larvae of H. armigera, for four days. Leaves, flowers and nectar were analyzed for nicotine, nornicotine and anabasine. The principal leaf alkaloid was nornicotine (mean: 28 m g/g dry mass) followed by anabasine (4.9 m g/g) and nicotine (0.6 m g/g). Nornicotine was found in low quantities in the flowers, but no nicotine or anabasine were recorded. The nectar contained none of the alkaloids measured. Larval growth was reduced when leaves of flowering plants were exposed to six larvae. As predicted by the optimal defense theory, herbivory had a localized effect and caused an increase in nornicotine concentrations in both undamaged top leaves of herbivore damaged plants and herbivore damaged leaves exposed to one and three larvae. The nicotine concentration increased in damaged compared to undamaged middle leaves. The nornicotine concentration was lower in damaged leaves of plants exposed to six compared to three larvae, suggesting that N. africa