Silicon nanoparticles mitigate oxidative stress of in vitro-derived banana (Musa acuminata ‘Grand Nain’) under simulated water deficit or salinity stress

Abstract

Climate change and rising sea levels increasingly threaten agriculture, especially in the coastal regions. Banana cultivars, especially the Cavendish clones, are sensitive to salinity stresses, which results in decreased production. In the current study, we evaluated the water deficit stress remediating effects of silicon nanoparticles (SiO2NPs) on micropropagated banana cv. “Grand Nain” - either under in vitro conditions in the laboratory or ex vitro in the greenhouse. In vitro water deficit was induced with polyethylene glycol (PEG-8000). Addition of in vitro SiO2NPs enhanced shoot growth and chlorophyll content. Malondialdehyde content (MDA) and electrolyte leakage (EL) were reduced in 3% PEG-stressed plants following the addition of the 150 mg/l SiO2NPs (38.73 nmole and 4.93%) compared with the control plants (51.67 nmole and 5.76%). In the greenhouse study, plants under salt and water deficit treatments were sprayed with SiO2NPs at (0, 200, 400 and 600 mg/l). Under salinity stress conditions, SiO2NPs improved photosynthesis as the stressed plants had similar chlorophyll content as control unstressed plants (23.33). SiO2NPs at 400 mg/l application increased K+ level (10.54%) and decreased Na+ levels (1.17%). Under simulated water deficit stress conditions, 600 mg/l SiO2NPs significantly increased K+ and K+/Na+ percent (10.37 and 14.40%) along with improvement in chlorophyll content index at all levels of SiO2NPs application. The overall results revealed that SiO2NPs application can improve chlorophyll content, induce K+ uptake, modulate Na+ levels and decrease cell wall damage in the treated plants comparing to the untreated plants under abiotic stress. Our results suggest that the application of SiO2NPs can help maintain plant integrity in the banana cultivar ‘Grand Nain’ under simulated abiotic stress.