小麦叶片表皮蜡质成分及含量分析

Analysis on Composition and Content of Leaf Cuticular Waxes of Wheat(Triticum aestivum)Detected by GC-MS

为了解小麦叶片表皮蜡质晶体结构及成分,以具有白霜状表型的小麦品系310为材料,在抽穗期选取小麦倒二叶,用扫描电镜观察叶片蜡质晶体结构,并采用气相色谱/质谱(GC-MS)分析其蜡质组分,以峰面积为指标,定量计算各蜡质组分的含量。结果表明,小麦叶片上表皮的蜡质晶体呈现致密的片状结构,下表皮呈现管状结构。抽穗期叶片的蜡质总含量为9.204±0.650μg·cm-2。其中,脂肪醇含量最高,为3.690±0.485μg·cm-2,占蜡质总量的40.37%;烷烃次之,含量为3.040±0.678μg·cm-2,占蜡质总量的32.88%;醛、酸、二酮分别为0.524±0.032μg·cm-2、0.469±0.040μg·cm-2、0.951±0.064μg·cm-2,分别占蜡质总量的5.65%、5.18%和7.12%;未鉴定出的成分为0.815±0.140μg·cm-2,占蜡质总量的8.79%。在叶片表皮蜡质总化合物中,C28醇分布最多,占化合物总量的32.16%;其次为C29烷烃,占化合物总量的18.72%。

In order to identify the cuticular wax components of wheat(Triticum aestivum),wheat line310was used as the material and its penultimate leaves were harvested at heading stage for GC-MS(Gas Chromatography-Mass Spectrometry)analysis,and the crystals of epicuticular wax was observed by scanning electron microscope at the same time.The results showed that the total leaf wax content was 9.204±0.650μg·cm-2.Fatty alcohols were the dominant components of leaf blade waxes,which were about 3.690±0.485μg·cm-2.The content of alkanes were 3.040±0.678μg·cm-2.The contents of aldehydes,acids and diketone were 0.524±0.032μg·cm-2,0.469±0.040μg·cm-2 and 0.951±0.064μg·cm-2,respectively.Unidentified compounds were 0.815±0.140μg·cm-2.Octacosanol was the major component of the fatty alcohols,and it accounted for32.16%of the total cuticular waxes,and then nonacosane accounted for 18.72%.The micromorphology of the epicuticular wax crystals observed on both sides of leaf surface by SEM showed that adaxialleaf surface was dominated by platelets crystals,while the abaxial leaf blade surface dominated by tubular structure crystals.The results laid a theoretical foundation for further studying on the waxes and wax biosynthesis pathway in wheat.