Abstract

FERRAROTTO, María  and  JAUREGUI, Damelis. Estudio de la maduración de vasos del metaxilema asociada al medio de crecimiento en raíces de soya (Glycine max (L.) Merr.). INCI [online]. 2005, vol.30, n.2, pp.87-92. ISSN 0378-1844.

Growing plants in controlled hydroponic environments is common in botanical research. However, the distribution and anatomy of the root system in this condition has to be considered as it may vary in response to the growing medium. Two soybean genotypes, ‘Doko’ and ‘Conquista’, of potential use in Venezuelan ecosystems, were evaluated. Growth of the root system and maturation stages of metaxylem vessels were determined, and the relative axial flow rate was estimated by the Hagen-Poiseuille law. Equal amounts of plantlets of both genotypes were simultaneously planted in plastic pots with sand and in a hydroponic system with nutrient solution only. At 33 days after planting, no distinct genotypic differences were observed in root dry weight and root surface area in plants growing in either condition. However, the length of individual roots integrating the same root system was higher in nutrient solution in both genotypes. In nutrient solution the maturation of vessels in both genotypes was observed farther from the root tip than in roots growing in sand. The estimated relative axial flow rate was higher in ‘Conquista’ growing in sand than in nutrient solution primarily, because at 4cm from the root tip the late metaxylem vessels were in a more advanced maturation stage with disintegrated protoplast. ‘Doko’ from the same growing medium and the same distance from the root tip presented less mature vessels. In nutrient solution the estimated relative flow rate was lower than in sand in both genotypes.

Keywords : Flujo Axial; Glycine max; Maduración; Metaxilema; Soya.