Genetic variability on arsenic accumulation and its impact on yield in rice (Oryza Sativa L.) under elevated arsenic in soils

Abstract

Arsenic (As) is a human chronic carcinogenic, that occurs in soil due to naturalweathering of rocks and anthropogenic activities. As (V) is taken up into rice plantsthrough phosphate transporters owing to their chemical analogy, while As (III) uptakeand translocation into grains are through the silicon transport pathway due to theirsimilarity in molecular size. A glasshouse experiment using genetically diverse ricecultivars was carried out to investigate the accumulation of As on grains and the effecton the rice yield. In this experiment, different rice varieties were grown on natural ricesoils and the same soil that spiked with As (10 mg/kg). Sodium arsenate(Na₂HAsO₄.7H₂O) was used for As spiking. Total As content in unpolished grains werequantified by inductively coupled plasma mass spectrometer (ICP-MS). In rice grainsobtained from control pots, the As content varied from 10.6 to 44.2 μg/kg compared tothe rice grown on As treated soils in which As content varied from 99.1 to 271 μg/kg.The arsenic content in rice ranked in the order of Kalu heenati ˃ Bg 300 ˃ Behethheenati ˃ Madathawalu ˃ Bg 357 ˃ Pachchaperumal > Suwadel ˃ At 362 > Pokkali >Kahawanu that were grown on As-spiked soils, indicating the influence of geneticdiversity on the accumulation. The As level in soil and varieties and also their interactionhad a significant impact (p < 0.01) on the As accumulation in grains. The highest yieldwas reported in Pokkali under both controls and As treated soils, while Suwadel showedthe lowest grain yield under the elevated As level followed by Kahawanu. The lowestyield loss was observed in Beheth heenati among others under As stress and followed byKahawanu, Madathawalu and Pokkali. The finding of this study suggested that thenative cultivar, Pokkali is a better candidate that maintaining a lower grain As level witha higher yield under As stress in soil hence can be used to develop future rice cultivars togrown on As-contaminated soils.