Morphogenesis of roots in edible canna - With special reference to adventitious roots

The morphological and anatomical features of the development of roots in ed ible canna (Canna edulis Ker-Gawl.) were investigated with special referenc e to its adventitious roots. A typical fibrous root system, which was compr ised of thick adventitious roots and thinner primary and secondary lateral roots, was formed in this species. In mature adventitious roots, the polyar ch stele with many vessels and the cortex with lacunae were unique features . There was no clear nodal structure in the stele of rhizome and the intima te interconnection of node and stelar vascular bundle was not observed. The re was no regularity of the development of adventitious roots as seen in gr amineous species. Compared with Musa species, the morphological and anatomi cal features were rather similar but the number of primordia and thickness of adventitious roots, the number of vascular bundles, and the size of lacu nae were smaller in edible canna. It is considered that the mode of develop ment and tissue structure of adventitious roots are related to the morphoge nesis of the root system to support the large aboveground part of this spec ies.