Nanosized titanium dioxide seed priming enhances the salt tolerance of the ornamental and medicinal plant Paeonia suffruticosa

摘要

Paeonia suffruticosa is a popular ornamental and medicinal plant it is vulnerable to saline stress. To find an effective seed treatment for P. suffruticosa under salt stress, the present study explored the effects of nanosized titanium dioxide (nano-TiO2) priming on the germination, growth and physiological response of P. suffruticosa under salt stress. The seeds were primed with different concentrations of nano-TiO2 for either 48 h or 72 h in a growth chamber. The germination characteristics, activities of superoxide dismutase, peroxidase, and catalase enzymes, net photosynthetic rate (Pn), chlorophyll content, lateral root number, and seedling biomass were evaluated. The results indicated that treatment with 2, 10, and 100 mg·L-1 nano-TiO2 significantly reversed the adverse effects of salinity stress on P. suffruticosa seed germination and increased the activities of superoxide dismutase, peroxidase, and catalase, the number of lateral roots and the content of chlorophyll in seedlings, thereby increasing seedling dry weights P. suffruticosa of when primed for 48 h. Nano-TiO2 priming for 72 h increased the Pn of P. suffruticosa seedlings, while priming for 48 h decreased Pn or had no significant effect. The findings suggest that priming seeds with 2, 10, or 100 mg·L-1 nano-TiO2 is an effective method for enhancing seed germination and early seedling growth in P. suffruticosa under salt stress.