Pre-Silicon Treatment Alleviates Drought Stress and Increases Antioxidative Activity in Kentucky Bluegrass (Poa pratensis L.)

Drought is an important environmental stress that adversely affects plant growth and causes a reduction in growth. Despite the expanded areas of use and the increasing usefulness of the turfgrass, research on the drought stress on turfgrass is still insufficient and there have only been few studies that investigated the effects of silicon on the drought-resistance of turfgrass. This study was performed to determine the effects of silicon on Kentucky bluegrass (Poa pratensis L.) after the application of drought stress. The daily amount of water or silicon solution was 250 mL per a pot. For 14 days, plants were treated with 0, 0.1 and 1.0 mM silicon solution for silicon treatments and with distilled water for control. Afterward, the plants were exposed to a 21-day drought treatment but the control received water as usual. Compared with the non-silicon treatment, application of silicon the increased the fresh weight of shoot and root as well as water content. The silicon pretreatments before drought significantly decreased chlorophyll contents, electrolyte leakage and the concentrations of malondialdehyde (MDA) and H₂O₂. However, the DPPH radical scavenging and glutathione (GSH) activities were significantly increased. Also, the responsive activities of the antioxidant enzymes encompassing superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD) were significantly enhanced. Our results suggest that silicon could help Kentucky bluegrass perform better under drought stress by increasing their antioxidant activities while decreasing lipid peroxidation.