Abstract Tetraena mongolica Maxim, a relic shrub of the paleo-Mediterranean flora, is normally accompanied in the Western Ordos desert by another plant species in the same taxonomic family, Zygophyllum xanthoxylum (Bunge) Maxim, and together they play a vital role in the ecology of the local environment. Z. xanthoxylum has been identified as having stronger drought tolerance than T. mongolica. As an important water barrier, cuticles were compared between these two relatives to better reveal the mechanism of their different drought tolerance. Z. xanthoxylum possesses more flattened wax crystals, lower epidermal permeability and higher water use efficiency (WUE) than T. mongolica. The composition of cuticular lipids were analyzed, and the results showed that Z. xanthoxylum had significantly higher total amounts of both cuticular wax and cutin monomers than T. mongolica, with all wax class (especially alkanes) and cutin monomer amounts being much higher in Z. xanthoxylum. Cuticle-associated genes were analyzed by transcriptome sequencing, and the results showed that more alkane synthesis genes were up-regulated in Z. xanthoxylum. These findings provide different cuticles on these two succulent xerophytes and reveal the relationships with their different drought tolerance. This study is helpful to reveal the function of plant cuticle in adaptability to extreme environments.

中文翻译：

---

鄂尔多斯高原（戈壁沙漠）两种肉质旱生植物、蒙古四叶草和夹竹桃(Bunge) Engl叶片表皮脂质的比较分析

摘要 Tetraena mongolica Maxim 是古地中海植物区系的一种遗迹灌木，在鄂尔多斯西部沙漠中通常伴随着同一分类科的另一种植物物种Zygophyllum xanthoxylum (Bunge) Maxim，它们共同在生态学中发挥着重要作用。当地的环境。Z. xanthoxylum 已被确定为比 T. mongolica 具有更强的耐旱性。作为重要的水屏障，比较了这两个亲戚之间的角质层，以更好地揭示其不同耐旱性的机制。Z. xanthoxylum 比 T. mongolica 具有更扁平的蜡晶体、更低的表皮渗透性和更高的水分利用效率 (WUE)。分析了表皮脂质的组成，结果表明 Z. xanthoxylum 的角质层蜡和角质单体的总量显着高于 T. mongolica，所有蜡类（尤其是烷烃）和角质单体的数量在 Z. xanthoxylum 中都高得多。通过转录组测序对角质层相关基因进行分析，结果表明，在黄花菜中更多的烷烃合成基因上调。这些发现为这两种多汁旱生植物提供了不同的角质层，并揭示了它们与不同耐旱性的关系。本研究有助于揭示植物角质层在适应极端环境中的作用。结果表明，更多的烷烃合成基因在花椒中上调。这些发现为这两种多汁旱生植物提供了不同的角质层，并揭示了它们与不同耐旱性的关系。本研究有助于揭示植物角质层在适应极端环境中的作用。结果表明，更多的烷烃合成基因在花椒中上调。这些发现为这两种多汁旱生植物提供了不同的角质层，并揭示了它们与不同耐旱性的关系。本研究有助于揭示植物角质层在适应极端环境中的作用。