Seed Testa Micromorphology of Thirty-eight Species of Allium (Amaryllidaceae) from Central Asia, and Its Taxonomic Implications
20 September 2016
LIN, Chen-yi; TAN, Dun-yanMicromorphological characteristics of the seed testa of thirty-eight species belonging to nineting sections and seven subgenera of Allium from Central Asia were evaluated with a scanning electron microscope (SEM) and taxonomically significant characters were found. The results showed that the epidermis consists of polygonal cells with different dimensions, cellular arrangement is tight or loose with or without reticulate tissue, and arrangement of cells is regular or irregular. The main variation was for anticlinal walls, for which the outline could be straight, straight to arched, arched or undulating like an S or U. Convex and (or) concave verrucate periclinal walls occurred in all species investigated. Based on the characteristics of the anticlinal and periclinal walls of the thirty-eight species, six groups of Allium were distinguished, and a dichotomous key for them was developed. Cellular arrangement and periclinal and anticlinal wall traits of the thirty-eight species of Allium were stable and distinct within a species but with great differences among species. This is the first report of seed testa micromorphology for twenty-four species of Allium. We conclude that seed epidermal characteristics provide useful and important information for distinguishing between species of Allium, and thus they have taxonomic significance.