Effects of sodium silicate on the growth and starch content in seeds of Mungbean (Vigna radiate L.) under salt stress

Abstract

Mungbean is known as an essential legume with high nutritional value for human beings. They are not only a source of vegetable proteins but they are also rich in vitamins and minerals. Salinity stress affects negatively mungbean growth, especially at germination and seedling stages. Thus, finding measures to limit the impact of salinity stress will have positive effects on mungbean production. The present study investigates the effectiveness of sodium silicate application (6, 12, 18, 24 mM) in alleviating the negative impact of salinity stress on seed germination and seedling growth. Physiological and biochemical changes during the growth of mungbean were analyzed. Our experiments showed that salinity stress dramatically impeded the germination of mungbean seeds. Under the salinity condition (125 mM NaCl), the germination index decreased by approximately 65 % compared to control plants. Salinity stress caused a significant decrease in leaf chlorophyll and leaf relative water content, whereas respiration rate, leaf epicuticular wax and carotenoid content increased in comparison to control plants. The application of 12 mM sodium silicate improved plant performances under salinity stress, as indicated by the increase in fruit and seed number, seed weight (72.33 mg), and starch content (0.51 g g−1) in seeds. Moreover, sodium silicate treatment induced an increase in chlorophyll a content (4.00 mg g−1), carotenoid content (2.50 mg g−1), and epicuticular wax content (3.67 µg cm−2) in the leaves of plants under salt stress. These results were scientific evidence that might help us to understand the role of Si in the improvement of the salt tolerance of mungbean.