LEAF DISSYMMETRY AND VEIN GROWTH FIELD - THE CASE OF THE TROPAEOLUM LEAF VEINS

The growth of the vein system of the leaf of Tropaeolum peltophorum was studied (i) at the vein level (analysis of the growth kinetics and of the growth field of the 7 primary veins) and (ii) at the limb level (comparison of the growth of the veins). The vein growth kinetics depend on the position of the vein on the leaf: there is a proximal / distal gradient and a bilateral gradient of the growth parameters (= variation of the temporal organization of the kinetics). The growth field of the veins (= local growth pattern) is also dependent on time and on vein position. Specific correspondences exist between singular points of the global growth curves (V-max,Gamma(min)) the variations of the growth field and the vein position. The spatio-temporal organization of the vein system growth is then characterized by positional variations of kinetic order which show the existence of a real morphogenetic dissymmetry.