新西兰婆婆纳属植物的红色（花青素）叶缘与酚类含量的增加无关。
Red (anthocyanic) leaf margins do not correspond to increased phenolic content in New Zealand Veronica spp.
机构信息
Wake Forest University, Department of Biology, Winston-Salem, NC 27106-7325, USA.
出版信息
Ann Bot. 2010 Apr;105(4):647-54. doi: 10.1093/aob/mcq005. Epub 2010 Feb 9.
BACKGROUND AND AIMS
Red or purple coloration of leaf margins is common in angiosperms, and is found in approx. 25 % of New Zealand Veronica species. However, the functional significance of margin coloration is unknown. We hypothesized that anthocyanins in leaf margins correspond with increased phenolic content in leaf margins and/or the leaf entire, signalling low palatability or leaf quality to edge-feeding insects.
METHODS
Five species of Veronica with red leaf margins, and six species without, were examined in a common garden. Phenolic content in leaf margins and interior lamina regions of juvenile and fully expanded leaves was quantified using the Folin-Ciocalteu assay. Proportions of leaf margins eaten and average lengths of continuous bites were used as a proxy for palatability.
KEY RESULTS
Phenolic content was consistently higher in leaf margins compared with leaf interiors in all species; however, neither leaf margins nor more interior tissues differed significantly in phenolic content with respects to margin colour. Mean phenolic content was inversely correlated with the mean length of continuous bites, suggesting effective deterrence of grazing. However, there was no difference in herbivore consumption of red and green margins, and the plant species with the longest continuous grazing patterns were both red-margined.
CONCLUSIONS
Red margin coloration was not an accurate indicator of total phenolic content in leaf margins or interior lamina tissue in New Zealand Veronica. Red coloration was also ineffective in deterring herbivory on the leaf margin, though studies controlling for variations in leaf structure and biochemistry (e.g. intra-specific studies) are needed before more precise conclusions can be drawn. It is also recommended that future studies focus on the relationship between anthocyanin and specific defence compounds (rather than general phenolic pools), and evaluate possible alternative functions of red margins in leaves (e.g. antioxidants, osmotic adjustment).
背景和目的
被子植物的叶缘呈红色或紫色较为常见，新西兰婆婆纳属植物约有 25%具有这种特征。然而，这种边缘颜色的功能意义尚不清楚。我们假设，叶缘的花青素与叶缘和/或整片叶子中较高的酚类含量相对应，这向取食叶缘的昆虫发出了低适口性或低叶片质量的信号。
方法
在一个共同的花园中，检查了五种具有红色叶缘的婆婆纳属植物和六种没有红色叶缘的植物。使用 Folin-Ciocalteu 法定量测定幼叶和完全展开叶片的叶缘和内部叶片区域的酚类含量。叶缘被取食的比例和连续取食的平均长度被用作适口性的替代指标。
主要结果
在所有物种中，与叶片内部相比，叶片边缘的酚类含量始终较高；然而，无论叶片边缘还是更内部的组织，其酚类含量在边缘颜色方面均无显著差异。平均酚含量与连续取食的平均长度呈负相关，表明对放牧具有有效抑制作用。然而，红色和绿色叶缘的取食量没有差异，具有最长连续取食模式的植物物种都是具有红色叶缘的。
结论
新西兰婆婆纳属植物的红色叶缘并不是叶片边缘或内部叶片组织总酚含量的准确指标。红色颜色也不能有效阻止对叶缘的取食，但在得出更精确的结论之前，需要进行控制叶片结构和生物化学变化（例如种内研究）的研究。此外，建议未来的研究重点关注花色苷与特定防御化合物之间的关系（而不是一般的酚类物质），并评估叶片中红色边缘的可能替代功能（例如抗氧化剂、渗透调节）。
Zotero 插件