Residual efficiency of iron-nanoparticles and different iron sources on growth, and antioxidants in maize plants under salts stress: Life cycle study

Exogenous application of iron (Fe) may alleviate salinity stress in plants grown on salt affected soils. This study aims to evaluate the comparative residual effects of iron nanoparticles (FNp) with other Fe sources including iron-sulphate (FS) and iron-chelate (FC) on the maize (Zea mays L.) crop grown under salt stress. All three Fe sources were applied at the rate of 15 and 25 mg/kg of soil before sowing of wheat and no amendments were used before sowing of maize crop. Results revealed that FNp at 25 mg/kg (FNp-2) substantially increased maize plant height, root length, root dry weight, shoot dry weight, and grain weight by 80.7%, 111.1%, 45.7%, 59.5%, and 77.2% as compared to normal and 62.6%, 81.3%, 65.1%, 78%, and 61.2% as compared to salt-stressed controls, respectively. The FNp-2 showed higher activities of antioxidant enzymes, such as superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase compared to salt stressed control (50.6%, 51%, 48.5%, and 49.2%, respectively). The FNp-2 showed the increase in levels of chlorophyll a content by 49.9%, chlorophyll b content by 67.2%, carotenoid by 62.5%, total chlorophyll content by 50.3%, membrane stability index by 59.1%, leaf water relative contents by 60.3% as compared to salt stressed control. The maximum Fe and Zn concentrations in maize roots, shoots, and grains were observed in FNp treatment as compared to salts stressed control. Higher application rates of Fe from all the sources remained better in alleviating the salinity stress in maize compared to their respective low rates. The study concluded that FNp alleviated salinity stress, increased nutrient uptake and enhanced the yield of maize grown on salt affected soil.