Effects of aqueous Moringa oleifera leaf extract on growth performance and accumulation of cadmium in a Thai jasmine rice—Khao Dawk Mali 105 variety

Abstract

The contamination of paddy fields and rice grains by cadmium (Cd) adversely affects human health. Thus, many approaches have been proposed to reduce the accumulation of Cd in rice. Here, we investigate the potential of aqueous Moringa oleifera leaf extract (AMOLE) in decreasing uptake and toxicity of Cd in a popular Thai jasmine rice variety, Khao Dawk Mali 105 (KDML105). Plants were grown in Petri dishes, a hydroponic system, and a pot system under different concentrations of Cd, in the presence and absence of AMOLE. In Petri dishes, Cd reduced the percentage of germination by 79%, but the treatment with 0.5 mg mL−1 AMOLE significantly increased the germination percentage. Moreover, AMOLE significantly decreased Cd accumulation in rice seedlings by 97%. In the hydroponics system, 0.5 mg mL−1 AMOLE decreased Cd content in shoots by 48%. Although no significant physiological changes in response to Cd treatments were observed in the pot system, a large amount of Cd was accumulated in rice roots. The AMOLE treatments significantly reduced Cd accumulation in rice shoots and decreased Cd content in milled grain by half compared to those without AMOLE treatment. We conclude that AMOLE reduced Cd toxicity, enhanced seedling growth, and reduced Cd accumulation in rice grains.