Iron Overload in the Root Environment of Rice (Oryza sativa- L) with a Miserable Nutrients Specification

Abstract

In waterlogged soils under low pH, Fe2+ availability increases and may reach toxic levels. The conditions of iron toxicity are quite well established over the World. The physiological effects of Fe2+ within plant with subsequent plants’ nutrients status are well documented in many literatures. Despite our current knowledge of the processes and mechanisms involved, iron toxicity, a function of growth conditions and the cultivar types remains as an important constraint to rice production, together with nutrients deficiency in the regional levels. To screen Fe tolerant cultivars and thus to evaluate the  mechanisms involved in response to excess Fe, experiment was carried out with rice cultivars – Ranjit, Siyal Sali and Mahsuri, grown by developing artificial Fe toxic conditions in the soils of experimental pots applying different Fe2+ concentrations (control- normal soil iron from rice field, +100, +200 and +300 ppm  respectively). The study of plants’ biochemical parameters confirmed the resistance of Mahsuri plants to Fe excess. With steady recovery of neutral pH and better chlorophyll contents, the root and shoot nutrients of Mahsuri were found to be higher compared to the plants of other two varieties when exposed to excess Fe. Except Fe and N in roots and shoots, the excess of Fe caused a negative impact on other nutrients in these vulnerable cultivars. Plants of Ranjit and Siyal Sali seem to be affected directly by Fe toxicity and also by the pseudo Fe toxicity, whereas Mahsuri seems to make use of the exclusion/and or avoidance mechanism to Fe overload.