Abstract
The adventitious roots of edible canna (Canna edulis Ker-Gawl.), are classified as the ‘vertical’ roots, which penetrate deep in soil, and the ‘horizontal’ roots, which run shallow underground. Most of the vertical roots are comprised of the basal ones, which generate in pairs at the nodal part of rhizome. From the viewpoint of functional differentiation of the two types of roots, their respiration rates were compared at different stages of growth, distances from stock and direction of root elongation by the use of a gas-phase oxygen electrode system. Root respiration rates decreased with age, but a difference between the two types of roots was not observed except in the early growth stage. Root activity, such as nutrient absorption in this crop, was considered to be performed mainly by a large quantity of horizontal roots rather than the qualitative difference between horizontal and vertical roots.