Nitric oxide mediated regulation of iron deficiency chlorosis in aerobic rice genotypes

Abstract

Iron deficiency chlorosis cripples aerobic rice on calcareous soils, yet nitric oxide's signaling role in rice iron acquisition is poorly understood. This research examined NO regulation of iron uptake in ten aerobic rice genotypes at the Swedish University of Agricultural Sciences, Uppsala (2022-2023). Plants grew in nutrient solution with adequate or deficient Fe, with and without 100 µM SNP as NO donor. Fe-efficient genotypes produced 2.1-2.8-fold more endogenous NO under deficiency. Exogenous NO raised root Fe by 28.6% and SPAD values by 19.4% in susceptible lines. A strong correlation (r = 0.87) linked NO with chlorophyll retention. NO appears to activate Strategy II iron acquisition through enhanced phytosiderophore release.