Structure of the cuticular transpiration barrier: role of epicuticular wax

叶-气界面是由植物角质层覆盖所有外表皮细胞壁形成的。角质层是细胞外亲脂性生物聚合物。它由角质和沉积在角质聚合物中的角质蜡（角质内蜡）和外表面上的角质蜡（表皮蜡）组成。众所周知，角质层蜡主要建立角质层的蒸腾屏障，因为在蜡提取后，角质层渗透性增加2-3个数量级。通常，表皮蜡的形成和外观受到环境影响的显着影响，通常认为这会影响蒸腾屏障。然而，它仍然是未知的，在何种程度上表皮蜡有助于蒸腾屏障的形成。在这里建议的研究项目中，将使用一种经过验证的方法，即在选择性地从角质层表面去除表皮蜡之前和之后测量3 H2O的角质层水渗透率。将通过扫描电子显微镜、气相色谱法和质谱法平行进行成功除蜡的验证和量化。这种结合的方法应该最终允许回答长期存在的问题，表皮蜡是否有助于表皮蒸腾屏障的形成或没有？

The leaf atmosphere interface is formed by the plant cuticle covering all outer epidermal cell walls. The cuticle is an extracellular lipophilic biopolymer. It is composed of cutin and cuticular wax deposited in the cutin polymer (intracuticular wax) and on the outer surface (epicuticular wax). It is well known that cuticular wax is mainly establishing the transpiration barrier of the cuticle, since upon wax extraction cuticular permeability increases by 2-3 orders of magnitude. Often formation and appearance of epicuticular wax is significantly affected by environmental influences and it is normally assumed that this affects the transpiration barrier. However, it is still unknown to what extent epicuticular wax contributes to the formation of the transpiration barrier. In the research project suggested here, a verified method, measuring cuticular water permeability of 3H2O before and after the selective removal of epicuticular wax from the cuticle surface, will be used. Verification and quantification of successful wax removal will be done in parallel by scanning electron microscopy, gas chromatography and mass spectrometry. This combined approach should ultimately allow answering the long-lasting question whether epicuticular wax contributes to the formation of the cuticular transpiration barrier or not?