Silicon (Si) has been verified to be a beneficial element for enhancing plant salt tolerance, but the mechanisms behind Si-mediated salt tolerance is still not fully understood. In this paper, seedlings of mung bean (Vigna radiata L.) growing in perlite culture matrix were treated with Si (0–2 mM K2SiO3) under NaCl (0–200 mM) stress, and the potential responding pathways involved in alleviating salt damage were investigated. The results showed that the biomass and chlorophyll content increased significantly by Si addition under salt stress. The soluble protein content increased about 17.8%, while soluble sugar and MDA decreased for 16.9 and 23.5%, respectively. The activity of ascorbate peroxidase and peroxidase increased about 50.3–52.4 and 27.7–33.7%. The results of scanning electron microscopy showed that Na+ content in leaves was higher than that in roots. RT-PCR results indicated that the transcription level of key ions transporter genes (POD, AT1, HKT1, Lsi1) were up-regulated after Si addition. These results revealed that Si application could enhanced salt tolerance by adjusting content of osmoregulatory substances, promoting antioxidant enzymes activity and up-regulating ions transporter genes expression. These results provide new insights into the potential mechanisms of Si-mediated salt tolerance in V. radiata plants.
Kang et al. (Tue,) studied this question.