叶表皮蜡质纹饰特征的种内变异——以青藏高原地区的紫花针茅和小叶棘豆为例

Intraspecific Variation of Leaf Epidermal Cuticle Waxes under Scanning Electronic Microscope:Stipa purpurea and Oxytropis microphylla from the Qinghai-Tibet Plateau

叶表皮在扫描电镜下的微形态特征,特别是蜡质纹饰的微形态特征,被认为具有重要的分类学和系统学价值。既往的叶表皮微形态特征的研究主要集中于种或种以上分类等级,而对种内微形态特征变异的研究较少。本研究以紫花针茅和小叶棘豆为研究对象,各选取29份及15份来自青藏高原不同地区的实验材料,在扫描电镜下观察叶表皮蜡质纹饰微形态特征。结果表明:两种植物的蜡质纹饰微形态特征在种内都存在较大的变异,推测该特征并不受单一因素的选择作用,生境的异质性导致蜡质纹饰的多态性。本研究建议在使用叶表皮微形态特征开展分类学和系统学研究时,应加大取样量并涵盖尽可能多的生境类型,才有可能阐明一个物种叶表皮微形态特征的变异范围。

Leaf epidermal microfeat^es under Scanning Electronic Microscope （ SEM）, especially microfeatures of cuticle waxes, are considered to be a valuable character in plant taxonomy and systematics. Previously studies of leaf epidermal microfeatures mainly focused on levels of species or above species, whereas intraspecific study was rare. In order to explore intraspecific variation of leaf epidermal microfeatures, we selected multiple materials of Stipa pur- purea and Oxytropis microphylla （29 and 15 samples, respectively） to observe the microfeatures of leaf cuticle waxes under SEM. The results revealed that these two species bearing high intraspecific variations of microfeatures of leaf cuticle waxes, and these variations lack of a strong correlation with any single biotic or abiotic factors, in contrast, it is affected by combined effects of multiple factors. Therefore, the use of microfeature of leaf cuticle waxes in taxonomical and systematic study will depend, to great extent, upon the detection of microfeature variation range, by extensive sampling along the whole distribution area.