Ultra-structure alteration via enhanced silicon uptake in arsenic stressed rice cultivars under intermittent irrigation practices in Bengal delta basin.

The study implements a periodical intermittent water cycle during rice cultivation providing insight potential in minimizing soil bio-available arsenic. Soil As concentrations were 34 ± 0.49 and 72.03 ± 0.54 mg kg-1 As respectively in two selected fields with rice cultivars gosai and satabdi, in comparison to 42.26 ± 0.37 and 83.69 ± 0.48 mg kg-1 in continuously flooded field soil, determined through ICP-MS. The study found higher translocation of silicon from soil to rice plant parts under intermittent irrigation having pH range of 7.6–9.4 and greater availability of soil organic content that in turn release more labile silicon from soil to aqueous phase for plant accumulation. This increased uptake of silicon strengthens rice shoots, nodes and leaf xylem-phloem integrity compared to conventional continuously flooded rice cultivation approach, suppressing the arsenic translocation, as observed under FE-SEM real-time imaging. Fresh plants were analysed for bioaccumulation and translocation factors of arsenic and silicon to justify the enhanced silicon uptake under proposed practice. Plant stress regulator enzymes viz. malondialdehyde (MDA), total protein, superoxide dismutase (SOD), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) from both conditions and found to be better in intermittent method over conventional practice with higher productivity. Image 1 • Implementation of intermittent irrigation in rice cultivation significantly reduces arsenic accumulation in rice plant. • Dry-wet irrigation practice renders the lesser arsenic mobilization involving soil physico-chemical parameters. • Soil silicon dissolution is enhanced under intermittent dry-wet phase from H 4 SiO 4 bound minerals. • Increased silicon uptake suppresses arsenic translocation and improves rice internal ultra-structure. • Stress markers are lower in silicon rich plants under intermittent irrigation over conventional flooding practice. [ABSTRACT FROM AUTHOR]