Resumo

FUENTES, Leticia et al. Physiological and biochemical response of Stylosanthes guianensis cv. CIAT-184 and Centrosema molle to sodium chloride stress . Pastos y Forrajes [online]. 2010, vol.33, n.2, pp. 1-1. ISSN 0864-0394.

A study was conducted on the effect of different concentrations of sodium chloride (NaCl) on seedlings of Stylosanthes guianensis cv. CIAT-184 and Centrosema molle, cultivated on topsoil. Fifteen days after the treatment fresh mass, dry mass, root/shoot ratio and biomass distribution were determined, as well as the concentration of soluble phenols, cell wall-bound phenols and total phenols, in addition to chlorophyll a, b and total chlorophyll. In both cultivars the roots were the most affected organs regarding fresh mass and there was a decrease of dry mass at high concentrations of NaCl. The root/shoot ratio showed an increase at 200 mM of NaCl in S. guianensis, while no significant changes were observed in C. molle. As the concentration of NaCl increased, the concentration of soluble phenols increased noticeably in the roots of both species, as well as total phenols; while in the leaves increases in the levels of soluble phenols were observed only in S. guianensis. The concentration of chlorophyll a and total chlorophyll significantly decreased at 200 mM of NaCl in both cultivars with regards to the control. The levels of chlorophyll b decreased in C. molle at 200 mM and remained constant in S. guianensis. The chlorophyll stability value showed highly significant differences in C. molle (-8,154 and 269,1 for 100 and 200mM of NaCl), unlike S. guianensis which showed higher stability (20,47 and 31,37). The chlorophyll a/b ratio decreased in Centrosema and no differences were observed among treatments in Stylosanthes.

Palavras-chave : Centrosema molle; chlorophylls; phenolic compounds; salinity; Stylosanthes guianensis.

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