Thorén L Magnus, Tuomi Juha, Kämäräinen Terttu, Laine Kari
Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
Present address: Department of Plant Ecology, Ecology Building, Lund University, SE-223 62 Lund, Sweden.
New Phytol. 2003 Aug;159(2):507-511. doi: 10.1046/j.1469-8137.2003.00816.x.
• Carnivory in plants is restricted to nutrient-poor and open habitats presumably because of high benefits and/or low costs of carnivory in these conditions. Carnivory is costly because the plants need specific adaptations to capture prey. Drosera rotundifolia produces sticky substances on its leaf surface to catch prey. These substances are primarily carbon-based, and their production can be expected to be lower in shade. The benefit of carnivory is in terms of the increased nutritional gain which will be low when inorganic nutrients are available in the growth medium. We expected that investment in carnivory would be lower in shade and nutrient-rich conditions. • A factorial experiment involving shading and the addition of inorganic nutrients confirmed these predictions in the carnivorous, perennial herb D. rotundifolia. • Plants growing in shade or in media with nutrients added had less sticky leaves and had reduced their investment in carnivory. • Interestingly, the observed changes in the stickiness of the leaves were in accord with the carbon/nutrient balance theory, whereas a carbon-based secondary compound, 7-methyljuglone, in the leaves did not respond to shading or nutrient addition.
• 植物的食肉习性仅限于营养贫瘠且开阔的栖息地，这大概是因为在这些条件下食肉的益处高和/或成本低。食肉是有成本的，因为植物需要特定的适应性来捕获猎物。圆叶茅膏菜在其叶表面产生粘性物质以捕捉猎物。这些物质主要基于碳，预计在阴凉处其产量会降低。食肉的益处在于营养获取增加，而当生长介质中有无机养分时，这种增加会很低。我们预计在阴凉和营养丰富的条件下，对食肉习性的投入会更低。
• 一项涉及遮荫和添加无机养分的析因实验证实了这些对食肉多年生草本植物圆叶茅膏菜的预测。
• 在阴凉处或添加了养分的介质中生长的植物，其叶子粘性较小，并且减少了对食肉习性的投入。
• 有趣的是，观察到的叶子粘性变化符合碳/养分平衡理论，而叶子中的一种基于碳的次生化合物7-甲基胡桃酮对遮荫或添加养分没有反应。
