Comparative study of physiological and growth parameters for sodium and iron toxicities in upland and lowland cultivars of Oryza sativa L.

Abstract

Abiotic stresses are common limitations to rice productivity worldwide. Sodium and iron toxicities affect the rice crop yield adversely. The aim of this study was to compare the effects of these toxicities on seedling growth and ionic distribution in (two upland: SK1 and Panderas and three lowland: Pokkali, MR211 and Firat) rice varieties. Sodium and iron toxicities (NaCl: 0, 80mM and 120mM and FeCl2: 0, 3.5mM and 7.5mM) were imposed separately, to three weeks old seedling for two weeks, using a hydroponic system. Results showed a significant adverse effect on growth traits with an increase in iron and sodium toxicities. Ionic distribution analysis of roots, leaves and flag leaves revealed that an increase in Na+ and Fe2+ ions reduced K+ uptake. Pokkali showed low accumulations of Na+ and Fe2+ in root, leaves and flag leaf in all stress levels of these toxicities. Firat showed high accumulation of Na+ and low accumulation of Fe2+ in high stress levels of these toxicities, respectively. MR211and Panderas showed high stress injury scores in both toxicities. Therefore, it is concluded that the tolerance for sodium and iron toxicities may be independent mechanisms as reflected by physiochemical analysis. However, ability to uptake potassium would help the seedling to ameliorate the effects of these toxicities.