《烟草栽培生理》-翻译作业-烟草11级-杜桂标

《烟草栽培生理》作业

任课教师：杨飞

班级：烟草2011级2班

姓名：杜桂标 学号：2011312961

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. africana rather invests in new growth as opposed to protecting older leaves under severe attack. The results indicate that the nornicotine-rich N. africana will be unattractive to herbivores and more so when damaged, but that potential pollinators will be unaffected because the nectar remains alkaloid-free even after herbivory.

摘要

取食在一些烟草属物种是已知诱导生物碱生成。本研究虫害诱导防御中去甲烟碱丰富的非洲烟草N. AFRICANA，唯一的烟草品种原产于非洲。我们测试的预言：1）N. AFRICANA将

有叶，花和花蜜生物碱较高水平的组成; 2）叶取食非洲棉铃虫棉铃虫将导致增加生物碱含量叶，花和花蜜; 3）增加生物碱含量草食动物损坏的工厂将幼虫生长产生负面影响。我们在大花盆在温室中，并暴露开花植物生长N. AFRICANA到棉铃虫1，3和6第四龄幼虫的密度，四天。叶，花和花蜜为尼古丁，降烟碱和假木贼进行了分析。委托人叶的生物碱是去甲烟碱（平均：28毫克/克干重），然后加入假木贼碱（4.9毫克/克）和烟碱（0.6毫克/克）。去甲烟碱被发现在低量在花丛中，但没有尼古丁或假木贼记录。花蜜包含没有测量的生物碱。幼虫生长减少，当开花植物的叶子被暴露到六幼虫。由于预测的最佳防守理论，虫食了局部的效果，导致在这两个完好的前叶受损草食动物和植物暴露在一个和三个幼虫草食动物损坏叶片增加去甲烟碱浓度。尼古丁浓度增加受损较完好的中部叶。降烟碱浓度较低，叶片暴露到六比三幼虫植物受损，这表明N. AFRICANA而投资于新的增长，而不是保护老叶受到严厉抨击。结果表明，去甲烟碱丰富N. AFRICANA将不能吸引食草动物多，所以当损坏，但潜在的授粉者将不会受到影响，因为即使花蜜后取食生物碱依然无。

Introduction

Plants have evolved a variety of chemical defenses to fend off a multitude of attackers [1]. Plants may use both constitutive and herbivore-induced defenses; these can involve primary as well as secondary metabolism, as in compensatory growth that occurs as a plastic phenotypic response to damage [2], [3]. Due to the cost of producing defensive chemicals [4], [5] plants may synthesize these chemicals only after damage has occurred [6]. Whilst constitutive defenses may be costly, a disadvantage of induced defenses is that there is a time delay between herbivore damage and a plant’s response to the damage [7], (but see [8]), essentially leaving the plant susceptible to attack before the induced defenses are activated. Based on the costs of a defense, the value of a plant part and the probability of that plant part being attacked by herbivores, the optimal-defense theory predicts that plant parts that are most valuable and most likely to be attacked will be allocated greatest defenses [9], [10], i.e. reproductive organs and organs necessary for survival [11]. Furthermore, induced defenses are also costly: when the roots of Nicotiana attenuata (Solanaceae) plants were treated with methyl jasmonate (a hormone induced by wounding), the induced plants produced 26% fewer seeds than non-induced controls [12], indicating that induced defenses can be detrimental to plant reproduction. Fitness reductions associated with herbivore resistance are common in plants (for reviews see [13], [14]).

Species of Nicotiana L. have been used as model systems to study the role of secondary metabolites in plant-herbivore and plant-pollinator relationships [15], [16], [17]. These studies have mostly concentrated on Nicotiana species with nicotine as the principal alkaloid. The four main alkaloids found in the genus Nicotiana are nicotine, nornicotine, anabasine and anatabine

[18] with nicotine occurring in almost all species [19]. Nicotine is highly toxic to many insects [8],

[20], but nornicotine and anabasine are known to be even more toxic than nicotine [21], [22].

Leaf damage in Nicotiana species has been shown to induce higher alkaloid levels in the vegetative tissues [23], [24], [25] and also in the flowers and nectar [17], [26], [27]. For example, leaf damage increases the nicotine concentration of N. attenuata, both lo …… 此处隐藏：9020字，全部文档内容请下载后查看。喜欢就下载吧 ……