Nicotiana section Alatae exhibits great diversity among species in floral morphology, mating system, and predominant pollinators. As a first step towards estimating nectar's role in floral evolution, we studied nectar traits to determine whether they vary in association with predominant pollinators and mating system. Daily phenology determines when nectar becomes available to pollinators and differed between hummingbird- and moth-pollinated species. Nectar volume and concentration varied significantly among most species and pollinator groups, but were inversely correlated, so that total energy was similar among most species. In general, nectar volume was positively correlated with corolla length. The autogamous species, N. plumbaginifolia, had a nectar volume that matched expectations based on corolla length, but with lower concentration and total energy than predicted by corolla length, while nectar volume was lower than predicted by corolla length in the autogamous population of N. longiflora. Sugar and amino acid components (determined through HPLC) were similar among species, although differences did exist. The nectar of most species was sucrose-dominant, but the autogamous N. plumbaginifolia had nectar that contained similar proportions of sucrose, glucose, and fructose. Many nectar traits varied in association with the predominant pollinators and, in some cases, with the mating system.

中文翻译：

---

与花性状、传粉媒介和交配系统相关的烟草科 Alatae（茄科）的花蜜性状

Nicotiana section Alatae 在花卉形态、交配系统和主要传粉媒介方面表现出极大的多样性。作为估计花蜜在花卉进化中的作用的第一步，我们研究了花蜜性状以确定它们是否因主要传粉媒介和交配系统而变化。每日物候决定花蜜何时可供传粉者使用，并且蜂鸟和蛾子授粉的物种之间存在差异。大多数物种和传粉者群体的花蜜量和浓度差异很大，但呈负相关，因此大多数物种的总能量相似。一般来说，花蜜量与花冠长度呈正相关。交配物种 N. plumbaginifolia 的花蜜量符合基于花冠长度的预期，但在 N. longiflora 的自交花序种群中，浓度和总能量低于花冠长度的预测，而花蜜量低于花冠长度的预测。糖和氨基酸成分（通过 HPLC 测定）在物种之间相似，但确实存在差异。大多数物种的花蜜以蔗糖为主，但自交的 N. plumbaginifolia 的花蜜含有相似比例的蔗糖、葡萄糖和果糖。许多花蜜性状因主要传粉媒介而异，在某些情况下，与交配系统有关。尽管确实存在差异。大多数物种的花蜜以蔗糖为主，但自交的 N. plumbaginifolia 的花蜜含有相似比例的蔗糖、葡萄糖和果糖。许多花蜜性状因主要传粉媒介而异，在某些情况下，与交配系统有关。尽管确实存在差异。大多数物种的花蜜以蔗糖为主，但自交的 N. plumbaginifolia 的花蜜含有相似比例的蔗糖、葡萄糖和果糖。许多花蜜性状因主要传粉媒介而异，在某些情况下，与交配系统有关。