Response of photosynthesis and superoxide dismutase to silica applied to creeping bentgrass grown under two fertility levels

Abstract

Responses of photosynthesis, Superoxide dismutase activity, and disease tolerance of creeping bentgrass (Agrostis palustris Huds. A.) to soluble potassium silicate (20.8% SiO₂) treatments was investigated under two fertilization regimes during 1997 and 1998. Potassium silicate was applied twice a month at 603 and 1205 mL 100 m⁻² under high or low fertilization regimes in the field, sampled from which were subjected to low soil moisture in a greenhouse environment. Foliar application of silicate stimulated antioxidant superoxide dismutase (SOD) activity in the bentgarss, especially under the high fertilization regime. Silicate increased photosynthetic capacity (PC) and chlorophyll content when applied at 603 mL 100 m⁻². Dollarspot disease incidence was significantly reduced with silicate treatment regardless of fertilization regime. Silicate did not significantly impact clipping weight. Under low soil moisture (‐0.05 MPa), silicate also enhanced SOD activity, PC, and chlorophyll content as well as root mass of bentgrass. Results suggest silicate may be used to enhance turfgrass drought and disease tolerance of turfgrass.

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