MORPHOLOGICAL AND ANATOMICAL CHARACTERIZATION OF THE COLEOPTILE OF TRITICUM-AESTIVUM WITH REGARD TO THE EVOLUTION OF FORMS WITH DIFFERENT PLOIDY LEVELS

Details of the morphology and anatomy of the coleoptile of wheat plants are given; these have not been described adequately previously. The investigations focussed on the hexaploid summer wheat Triticum aestivum L. cv. Hatri, and three taxa with different ploidy levels.In darkness the longitudinal growth of the coleoptile was delayed by nearly 24 h but the final length, reached after 120 h, was double that of coleoptiles of plants cultivated under continuous light. As soon as the coleoptile has grown, the primary leaf pushes through a pore pre-formed during the meristematic stage and located 1-1·5 mm behind the apex. The pore is stabilized mechanically by anastomosing of the originally free ends of the vascular bundles, as well as by increased lignification in this region. The species investigated differ in length, f. wt and d. wt, size of epidermal cells, and especially in the size of guard cells of the coleoptiles. The number of parenchyma layers, however, shows no specificity. © 1990 Annals of Botany Company.