Plant secondary metabolites in nectar: impacts on pollinators and ecological functions
Plant secondary metabolites in nectar: impacts on pollinators and ecological functions
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DOI：
10.1111/1365-2435.12761
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发表时间：
2017
影响因子：
5.2
通讯作者：
P. Stevenson;S. Nicolson;Geraldine A. Wright
中科院分区：
文献类型：
--
作者：
P. Stevenson;S. Nicolson;Geraldine A. Wright
1.次生代谢产物在植物防御食草动物中的生态功能已得到充分证实，但它们在植物与传粉者相互作用中的作用不太明显。花蜜是传粉者的主要奖励，因此许多物种的花蜜中出现防御化合物是出乎意料的。然而，越来越多的证据支持这些成分对植物和传粉者的各种潜在益处。2.花蜜中的次级代谢产物可能对访花者有毒或具有排斥性，但它们也可能未被发现或使花蜜具有吸引力。例如，花蜜中的咖啡因提高了传粉者对与食物奖励相关的线索的记忆，并增强了花粉的传递。所有这些影响都取决于花蜜代谢物的浓度，因此应该在一系列生态相关剂量下进行实验评估。3.有益的影响可能包括以下几点：a）增加植物-传粉者相互作用的专门化，B）保护花蜜不被抢劫或盗窃，以及c）保护花蜜中的营养物质不被微生物降解，减少访花者的微生物疾病水平。4.这篇综述综合了最近文献中的证据，支持选择花蜜中的次生代谢产物作为一种适应，推动植物和它们的传粉者之间的共同进化。然而，它们在花蜜中的存在可能仅仅是它们在植物的其他地方发生防御的结果（多效性）。我们提请注意，需要进行研究，证明对植物的益处，暴露水平的重要性以及对目标物种的影响，而不仅仅是目前对生物碱和蜜蜂的重视。
1. The ecological function of secondary metabolites in plant defence, against herbivores is well established, but their role in plant-pollinator interactions is less obvious. Nectar is the major reward for pollinators, so the occurrence of defence compounds in the nectar of many species is unexpected. However, increasing evidence supports a variety of potential benefits for both plant and pollinator from these components. 2. Secondary metabolites in nectar can be toxic or repellent to flower visitors, but they can also go undetected or make nectar attractive . For example, caffeine in nectar improves pollinator memory for cues associated with food rewards and enhances pollen transfer. All of these effects depend on the concentration of nectar metabolites so should be evaluated experimentally at a range of ecologically relevant doses. 3. Beneficial effects may include the following: a) increasing specialization in plant-pollinator interactions, b) protecting nectar from robbery or larceny, and c) preservation of nutrients in nectar from microbial degradation and reducing microbial disease levels in flower visitors. 4. This review synthesises evidence from recent literature that supports selection for secondary metabolites in floral nectar as an adaptation that drives the co-evolution between plants and their pollinators. However, their presence in nectar could simply be a consequence of their occurrence elsewhere in the plant for defence (pleiotropy). We draw attention to the need for studies demonstrating benefits to the plant, the importance of levels of exposure and a effects on target species beyond the current emphasis on alkaloids and bees.