Comprehensive analysis revealed that titanium dioxide nanoparticles could strengthen the resistance of apple rootstock B9 to saline-alkali stress

Abstract

Apple growth and development can be adversely affected by saline–alkali stress, which has become a significant factor restricting the high yield of the apple industry. In recent years, nanomaterials have become a potential source for plant growth and development. Titanium dioxide nanoparticles (TiO2NPs) play an important role in multiple plant development processes, including mitigating environmental stress. In this study, one-year-old apple rootstock B9 stem cuttings were used as research objects. Different concentrations of TiO2NPs were applied to the roots before saline–alkali treatment. Principal component analysis showed that 1 g kg−1 TiO2NPs treatment had the best effect in alleviating the stress for B9. It significantly reduced the damage to B9 under salt–alkali stress, increased the content of photosynthetic pigment, enhanced the performance of Photosystem II, and promoted photosynthesis. At the same time, the content of K+ was increased, and the ion toxicity was alleviated. In addition, TiO2NPs have also been shown to reduce B9 cell damage and lipid peroxidation, increase antioxidant enzyme activity, and regulate the accumulation of solutes. Overall, this study provides a theoretical basis for TiO2NPs to mitigate the adverse effects of plants under saline–alkali stress and provides useful insights for managing other plants affected by global salinity and alkalinity.