Abstract

The benefits of silicon (Si) have been studied in various plants species. Thus, Si promotes the production of antioxidant compounds such as phenol compounds, which are related with defense mechanisms and structural support in plants. In this study we investigated Si uptake and antioxidant performance of ryegrass plants cultivated under different Si -doses and -sources. A pot experiment was conducted with ryegrass (Lolium perenne L., cv. Nui) on an Andisol. Plants were fertilized with Si (calcium silicate or sodium silicate) at doses of 0, 250, 500 or 1000 mg Si/kg soil. At harvest, the dry weight and Si concentration of shoots and roots were determined on samples of two consecutive cuts. Additionally, phenols concentration and lipid peroxidation were analyzed in plant tissues as an index of oxidative damage. No differences in dry weight (DW) were observed in the first cut by effect of Si supply. However, for the second cut, DW increased by the addition of all doses of sodium silicate and the highest of calcium silicate. The results also showed that Si uptake in shoots and roots were increased by the application of Si. Furthermore, a significant reduction of lipid peroxidation was found when increasing doses of Si (sodium silicate or calcium silicate) were applied. At all Si supply levels, the decrease of the oxidative damage was accompanied by an increase of the concentration of phenolic compounds. Our results indicate that Si exert a benefic effect on the antioxidant system decreasing oxidative stress in ryegrass plants. Acknowledgements: FONDECYT project 1120901, and Dirección de Investigación of the Universidad de La Frontera (Temuco, Chile).