• Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well‐described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen.
• We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols.
• 24‐methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (C‐24 alkylation, ring B desaturation). Plants originating in tropical‐like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds.
• Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.

中文翻译：

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花粉甾醇与系统发育和环境有关，但与传粉媒介协会无关

• 植物甾醇是具有基本结构和调节功能的主要植物代谢物。它们也是不能合成甾醇的植食性昆虫（包括传粉昆虫）的必需营养素。尽管植物营养组织的组成和多样性已得到充分描述，但很少有研究检查花粉中植物甾醇的多样性。
• 我们对 122 个植物物种（105 个属，51 个科）中的 25 种花粉植物甾醇进行了定量，以确定它们在植物分类群中的组成和多样性。我们检索了有关植物系统发育、环境条件和该物种传粉媒介的文献和数据库，以研究与花粉甾醇的关系。
• 24-亚甲基胆固醇、谷甾醇和异岩藻甾醇是最常见和最丰富的花粉甾醇。我们发现了 12 种甾醇、甾醇总含量和甾醇多样性的系统发育聚类，以及反映其潜在生物合成途径（C-24 烷基化、B 环去饱和）的甾醇分组。起源于热带气候（较高的年平均温度、较低的季节性温度、最潮湿的季度降水量较高）的植物更有可能记录较高的花粉甾醇含量。然而，花粉甾醇的组成和含量与授粉媒介没有明显的关系。
• 我们的研究首次表明花粉甾醇多样性在系统发育上是聚类的，并且花粉甾醇含量可能会适应环境条件。