Several mineral compounds influence adventitious rooting, and those containing boron and calcium, play an important role. They are associated to the enzyme regulation, cell division, cellular metabolism (induction stage) and roots enlargement (expression stage). The aims of this work were to study the variation of the endogenous calcium and boron concentrations along the rooting, and determine their optimal concentrations in the rooting basal medium of Nothofagus nervosa. Significant variation in endogenous calcium concentrations was detected along the rooting phase, strongly correlated with rhizogenesis phenomenons and linked to total peroxidase variation as cited elsewhere. Calcium and boron concentrations in the basal medium significantly affected the rooting. Treatment containing 60 mg.L-1 Ca and 1 mg.L-1 B produced root formation in fewer days than other combinations. The variation of these nutrient concentrations in the medium is a useful tool to improve microcutting rooting. Roots are obtained earlier and in a shorter period of time, finally resulting in more homogeneous microplants with a better developed rooting system.

Fil: Curvetto, Nestor Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina

Fil: Martínez Pastur, Guillermo José. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Arena, Miriam Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina