The only African wild tobacco, Nicotiana africana: alkaloid content and the effect of herbivory.
The only African wild tobacco, Nicotiana africana: alkaloid content and the effect of herbivory.
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DOI：
10.1371/journal.pone.0102661
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Krüger K
中科院分区：
文献类型：
--
作者：
Marlin D;Nicolson SW;Yusuf AA;Stevenson PC;Heyman HM;Krüger K
已知一些烟草物种的食草性可以诱导生物碱的产生。这项研究考察了富含降尼古丁的非洲烟草N.africana的食草动物诱导的防御，这是唯一一种原产于非洲的烟草物种。我们检验了以下预测：1)非洲棉铃虫将含有高组成水平的叶、花和花蜜生物碱；2)非洲棉铃虫对叶片、花和花蜜的食草性将导致叶片、花和花蜜中生物碱含量增加；3)被草食动物损害的植物中生物碱浓度增加将对幼虫的生长产生负面影响。我们在温室的大盆栽中种植非洲棉铃虫，并将开花植物暴露在棉铃虫一龄、三龄和六龄四龄幼虫的密度下，为期四天。对烟叶、花朵和花蜜中的尼古丁、去甲烟碱和烟碱进行了分析。主要的叶生物碱是去甲烟碱(平均为28微克/克干重)，其次是烟碱(4.9微克/克)和烟碱(0.6微克/克)。在花朵中发现了少量的去甲烟碱，但没有记录到尼古丁或烟碱。花蜜中不含有所测量的生物碱。当开花植物的叶片暴露于6头幼虫时，幼虫的生长受到抑制。根据最优防御理论的预测，食草动物具有局部效应，并导致食草动物受害植株顶叶和食草动物受害叶片暴露于1头和3头幼虫的去甲烟碱浓度增加。受害中部烟叶烟碱浓度高于未受害中部叶片。与3只幼虫相比，暴露于6只幼虫的植物受损叶片中去甲烟碱的浓度较低，这表明非洲新冠更愿意投资于新的生长，而不是在严重攻击下保护较老的叶片。结果表明，富含降尼古丁的非洲野百合对食草动物没有吸引力，受到损害时更具吸引力，但潜在的传粉者不会受到影响，因为即使在食草后，花蜜也不含生物碱。
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 µg/g dry mass) followed by anabasine (4.9 µg/g) and nicotine (0.6 µg/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.
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影响因子：
2.3
作者：
BALDWIN, IT;OHNMEISS, TE
通讯作者：
OHNMEISS, TE
影响因子：
2.3
作者：
Baldwin, IT
通讯作者：
Baldwin, IT
DOI：
10.1073/pnas.95.14.8113
发表时间：
1998-07-07
影响因子：
11.1
作者：
Baldwin, IT
通讯作者：
Baldwin, IT
影响因子：
7.2
作者：
Kessler, Danny;Bhattacharya, Samik;Baldwin, Ian T.
通讯作者：
Baldwin, Ian T.
影响因子：
2.7
作者：
BALDWIN, IT;SCHMELZ, EA
通讯作者：
SCHMELZ, EA