Evaluation of Growth Parameters and Biochemical Markers of Corn Plants Under Saline Stress

Abstract

This study aimed to investigate the effect of salinity on growth parameters and oxidative stress markers in leaves and roots of two sweet corn genotypes: BR 427III, obtained from Embrapa Milho e Sorgo, and Tropical Plus®, a commercial hybrid. The genotypes were kept in 15-L pots with typical dystrophic red latosol soil, and irrigated with NaCl solution (0, 25, 50, 100, 150 and 300 mM). At 105 days after planting, the samples were collected, immediately frozen in liquid nitrogen, and stored at -80 ºC for posterior analyses.  After this period, it was verified that, while NaCl concentration increased, there was a decrease in leaf and root fresh and dry masses as well as in shot and root lengths of both evaluated genotypes. A decrease in the stem diameter of BR427III genotype plants and in the chlorophyll index of both genotypes was observed. Sodium accumulation in the root and leaves increased according to the stress severity; however, potassium content reduced in both roots and leaves. Proline content increased significantly in the leaves of both evaluated genotypes when exposed to higher concentrations of NaCl. On the other hand, malondialdehyde content decreased in leaves and root of Tropical Plus genotype, where an increase in electrolyte overflow from membrane damage caused by stress severity was observed.