Efecto de un brasinoesteroide sintético (DAA-6) sobre el crecimiento del vástago y las raíces de la caña de azúcar

Abstract

Brassinosteroid were accepted in 1996 as a new class of plant growth regulators. Information about its effects on sugarcane growth and development is scarce; moreover there are few reports about the dose-effect relationship even for other plant species. The natural concentrations of this plant growth regulator are very low, between 10-7 and 10-1 ppm depending on the tissue; however, the analogues of brassinosteroid produced in Cuba, have been used for field application at relatively large concentrations (1-0,01 ppm). The objective of this paper is to find out the effect of the DAA-6 (BIOBRAS-6) on the sugarcane root and shoot growth and to determine the effect of concentration on growth. A Cuban sugarcane variety (Ja 60-5) with difficulties for rooting was selected for the experiments. Nodes from the upper third of the cane were soaked in DAA-6 solutions different in con-centration (1 to 10-6 ppm); a control with distill water was used. The kinetic of rooting, total root length per node and shoot height were measured. The maximum stimulation effect on root and shoot growth, after ten days of treatment, was found to occur at 10-6 and 10-4 ppm respectively. The root emission per node increased with all treatment with a maximum at the lowest concentration assayed: 10-6 ppm. Rooting was earlier with all DAA-6 treatments. It is discussed that the stimulating effect of DAA-6 on sugarcane root and shoot growth could be due to its effect on the activity of xyloglucan endotransglycosylases and the in-crease of the cell membranes permeability to water.