ABSTRACT

Background

The cuticle, by ensuring protection against water loss, was a key innovation in plant terrestrialisation. This layer is characterised by the cutin matrix embedded and covered with cuticular waxes. In this study we describe the cuticular waxes on gametophytes of several species of liverworts and mosses, including Brazilian endemics.

Methods

Cuticular waxes from 34 species from different locations in the São Paulo state, Brazil, were analysed by gas chromatography coupled with mass spectrometry. The compounds were identified based on mass spectra fragmentation. The morphology of the epicuticular waxes was analysed using scanning electron microscopy.

Main results

The wax content in the liverwort species varied from 0.1 to 4 μg cm⁻², while in mosses the values ranged from 0.02 to 0.6 μg cm⁻². The main classes of wax compounds were fatty acids, alkanes, and primary alcohols. Aldehydes, alkenes, esters, ketones, triterpenes, a diacid and a secondary alcohol had a more restricted distribution. The morphology of the epicuticular waxes was predominately of the film type.

Conclusions

In general, wax content was higher in the liverworts than in the mosses. Fatty acids and alkanes were the most common class whilst alkenes, ketones, diacid, and a secondary alcohol are described for the first time as wax compounds in bryophyte gametophytes.

中文翻译：

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一些巴西苔类植物和苔藓中表皮蜡的形态和化学成分

摘要

背景

通过确保防止水分流失，角质层是植物陆地化的一项关键创新。该层的特点是角质基质嵌入并覆盖有角质层蜡。在这项研究中，我们描述了几种苔类植物和苔藓（包括巴西特有植物）配子体上的角质层蜡质。

方法

来自巴西圣保罗州不同地点的 34 个物种的表皮蜡通过气相色谱和质谱联用进行了分析。基于质谱碎片鉴定化合物。使用扫描电子显微镜分析表皮蜡的形态。

主要结果

苔类植物中的蜡含量从 0.1 到 4 μg cm ^-2不等，而苔藓中的蜡含量从 0.02 到 0.6 μg cm ^-2不等。蜡化合物的主要类别是脂肪酸、烷烃和伯醇。醛、烯烃、酯、酮、三萜、二酸和仲醇的分布更为有限。表皮蜡的形态主要是薄膜类型。

结论

一般来说，苔类中的蜡含量高于苔藓中的蜡含量。脂肪酸和烷烃是最常见的类别，而烯烃、酮、二酸和仲醇首次被描述为苔藓配子体中的蜡化合物。