Study on mechanism of silicon alleviating Cd stress in pakchoi

Cadmium (Cd) pollution is a widespread issue that threatens food safety and human health. Pakchoi is a well-liked vegetable, however, its leaves accumulate Cd. Consuming pakchoi grown in Cd-polluted regions can lead to severe health consequences. This study combines transcriptome and physiological experiments to explore the mechanism of silicon (Si) in alleviating Cd stress, improving yield and quality of pakchoi. The results showed that by regulating the expression of Cd absorption and transport genes in pakchoi, Si inhibits Cd absorption and transfer from roots to shoots of pakchoi and reduces the accumulation of Cd in pakchoi roots and shoots. Additionally, Si increased catalase and ascorbate peroxidase activities, decreased hydrogen peroxide and malondialdehyde, and alleviated Cd-induced oxidative stress. The application of Si inhibited chlorophyll degradation caused by Cd, enhanced the photosynthesis in pakchoi. Furthermore, Si inhibited the transport of nitrate to shoots by suppressing the expression of BrNRT1.1 and BrNRT1.2. Meanwhile, Si application can increase the contents of vitamin C, glucosinolates, carotenoids, calcium, iron and zinc in pakchoi leaves, improving its edible quality. These results indicate that silicon application is an effective method to alleviate cadmium stress in crops, which provides a feasible way to improve food safety in Cd-polluted areas.