A light microscopic study of the central metaxylem ontogenesis in the root of barley (Hordeum distichum L.)

Abstract

The cells of the central metaxylem in the barley root differentiate from isodiametrical meristematic cells into mature cylindrical vessel members of maximal length up to 1,3 mm [4]. The prospective cells of the central metaxylem divide only briefly and the mitosis soon passes into endomitosis with a continuing DNA synthesis, thus giving rise to endopolyploid nuclei with the DNA content of as much as 32C [4]. During the differentiation of the central metaxylem in the barley root, changes have been followed of the size of vessel members, their activity and organization of their protoplasts with the light microscope. Seedlings of barley (Hordeum distichum L., cv. Slovenský dunajský trh) were grown on sheets of moist filter paper at 25 °C. Segments of primary roots were fixed by glutaraldehyde and osmium tetroxide and embedded into Durcupan ACM Fluka. Approximately 1 μam thick sections were stained with toluidine blue and basic fuchsine (A. Lux, in press).