Abstract

BACKGROUND: Green-tea-synthesized copper oxide nanoparticles (CuO NPs) and S-nitrosoglutathione (GSNO), a nitric oxide (NO) donor, were applied individually and in combination to lettuce leaves. We aimed to investigate whether a combined application of CuO NPs and GSNO might enhance plant growth when compared to individual treatments and the control group. RESULTS: Spherical CuO NPs (13.4 ± 0.1 nm) at 50 μg mL−1 and/or GSNO at 100 μmol L−1 were individually and simultaneously sprayed onto lettuces leaves. All treatments had a positive effect on plant growth, and the administration of CuO NPs + GSNO promoted a threefold increase in lettuce dry weight. The treatments did not change plant transpiration, and all treatments enhanced instantaneous carboxylation efficiency compared to control. In the roots, all treatments enhanced the levels of S-nitrosothiol in the following order: CuO NPs < GSNO < CuO NPs + GSNO. Administration of GSNO significantly increased total phenolic content (twofold) and flavonoid content (fourfold) compared to the control group. All treatments increased the leaf levels of K, Na, Ca, Mg and S compared to the control group. CONCLUSION: All treatments promoted positive effects on lettuce growth, and no oxidative damage was observed, under the experimental conditions evaluated. A combined administration of CuO NPs and GSNO enhanced important physiological, biochemical and nutritional parameters of lettuces. © 2021 Society of Chemical Industry.