Millett Jonathan, Jones Roger I, Waldron Susan
Department of Biological Sciences, Lancaster University, Lancaster LA1 4YQ, UK.
Present address: Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, UK.
New Phytol. 2003 Jun;158(3):527-534. doi: 10.1046/j.1469-8137.2003.00763.x.
• The contribution of insect prey to total N in the carnivorous plants, Drosera rotundifolia and D. intermedia, was quantified in situ and without any experimental manipulation using natural abundance stable isotope analysis. • Samples of D. rotundifolia and D. intermedia, insects and noncarnivorous reference plants were collected from three contrasting locations across Britain. The proportion of Drosera nitrogen obtained from insect prey was calculated by a mixing model using δ N values from the different plant groups. • The mean proportion of Drosera N derived from prey was 50%. There were significant differences in this proportion between sites, and significant differences within sites. There were significant differences between plant tissues and a significant negative relationship between the proportion of N derived from prey and the C : N ratio of Drosera tissues. • There was little evidence of differences in prey capture/utilisation in response to N availability, possibly due to a limited range in available N between the sites. However, evidence of a positive benefit of prey capture was apparent through the decrease in C : N ratio with increasing prey N concentrations in the plants.
• 利用自然丰度稳定同位素分析，在原位且无任何实验操作的情况下，对食虫植物圆叶茅膏菜和中间茅膏菜中昆虫猎物对总氮的贡献进行了量化。
• 从英国三个不同地点采集了圆叶茅膏菜、中间茅膏菜、昆虫和非食虫参考植物的样本。利用不同植物组的δN值，通过混合模型计算了茅膏菜从昆虫猎物中获取的氮的比例。
• 茅膏菜从猎物中获取的氮的平均比例为50%。该比例在不同地点之间存在显著差异，在同一地点内也存在显著差异。植物组织之间存在显著差异，且从猎物中获取的氮的比例与茅膏菜组织的C:N比之间存在显著的负相关关系。
• 几乎没有证据表明猎物捕获/利用情况会因氮的有效性而有所不同，这可能是由于各地点之间可利用氮的范围有限。然而，随着植物中猎物氮浓度的增加，C:N比降低，这表明猎物捕获具有明显的积极益处。
