Chlorophyll fluorescence and lipid peroxidation changes in rice somaclonal lines subjected to salt stress

The aim of the present work was to explore physiological changes provoked by somaclonal variation in response to salinity. Two parental cultivars (La Candelaria and Yerua) and their derived somaclones were used as a source for breeding new rice lines with improved salt tolerance. We studied the effect of NaCl salt stress on chlorophyll fluorescence-related parameters, such as the maximum quantum yield of primary PSII photochemistry (Fv/Fm) and the performance index for energy conservation from photon absorbed by PSII antenna (PIABS). In addition malondialdehyde (MDA) content and leaf temperature (LT) responses were also measured. In somaclonal lines, Fv/Fm, PIABS, MDA and LT showed coefficients of variation of 13.7, 39.3, 25.5, and 3 %, respectively, for La Candelaria and 1.4, 17.6, 34.4 and 3 % for Yerua. However, the fragrant character did not differ in the aromatic somaclonal lines with respect to their parentals. Our results suggest that the Fv/Fm ratio would not be as good marker of PSII vitality as PIABS for salinized rice somaclones, unless they are highly susceptible to salinity. On other hand, the MDA content showed a strong negative correlation with the PIABS content in somaclones of both rice cultivars, suggesting that MDA levels could also be used as an oxidative damage index in rice somaclones.