Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
Sci Rep. 2024 May 25;14(1):11992. doi: 10.1038/s41598-024-62626-7.
Nature is aglow with numerous captivating examples of UV-fluorescence in the animal kingdom. Despite a putative role as a visual signal, exploration of UV-fluorescence in plants and its role in plant-animal interactions is lagging in comparison. Almost 50 years ago, UV-fluorescence of floral nectar, a crucial reward for pollinators, was reported for 23 flowering plant species. Since this intriguing discovery, UV-fluorescent nectar has only seldom been addressed in the scientific literature and has not been scrutinized in a phylogenetic or ecological context. Here, we report the prevalence of vibrant UV-fluorescent floral nectar across the family Cleomaceae, including the first photographic documentation in vivo colour for flowering plants. Though Cleomaceae flowers are morphologically diverse varying in colour, nectary prominence, and nectar volume, UV-fluorescent floral nectar may be a ubiquitous characteristic of the family. Fluorescence spectra show that the identity and number of fluorescent compounds in floral nectar may differ among Cleomaceae species. As Cleomaceae pollinators range from insects to bats and birds, we suggest that the UV-fluorescent floral nectar not only functions as a visual cue for the diurnal pollinators but also for the nocturnal/crepuscular pollinators in low light settings.
自然界中有许多令人着迷的动物王国中的 UV 荧光现象的例子。尽管 UV 荧光可能具有视觉信号的作用，但与动物相比，植物中的 UV 荧光及其在植物-动物相互作用中的作用的研究还远远不够。大约 50 年前，人们报道了花卉花蜜的 UV 荧光，花蜜是传粉者的重要奖励，当时涉及 23 种开花植物物种。自这个有趣的发现以来，UV 荧光花蜜在科学文献中很少被提及，也没有在系统发育或生态背景下进行深入研究。在这里，我们报告了在整个山柑科中存在鲜艳的 UV 荧光花卉花蜜，包括首次对活体开花植物的颜色进行的摄影记录。尽管山柑科的花朵在颜色、蜜腺明显度和花蜜量上形态多样，但 UV 荧光花蜜可能是该科的普遍特征。荧光光谱表明，花蜜中荧光化合物的种类和数量可能因山柑科物种而异。由于山柑科的传粉者从昆虫到蝙蝠和鸟类不等，我们认为 UV 荧光花蜜不仅是白天传粉者的视觉线索，而且在低光照条件下也是夜间/黄昏传粉者的视觉线索。
