Silicon influences growth and mycorrhizal responsiveness in strawberry plants.

Effect of silicon (Si) on the response of strawberry (Fragaria × ananassa var. Parus) plants to arbuscular mycorrhizal fungus (AMF) was studied under growth chamber conditions. Plants were grown in perlite irrigated with nutrient solution without (- Si) or with (+ Si) 3 mmol L(-1) Si (~ 84 mg L(-1) Si as Na(2)SiO(3)) in the absence (- AMF) or presence (+ AMF) of fungus. Dry matter production, root colonization rate, photosynthesis rate and water relation parameters were all improved by both Si and AMF, and the highest amounts were achieved by + Si + AMF treatment. Mycorrhizal effectiveness increased by Si treatment associated with higher Si concentration in the + AMF plants. Leaf concentrations of total soluble and cell wall-bound phenolics were increased by Si accompanied by the enhanced activity of phenylalanine ammonia lyase, but not polyphenol oxidase. Profile of phenolics compound revealed that gallic acid, caffeic acid, epicatechin, chlorogenic acid, ellagic acid and kaempferol increased by both Si and AMF treatments, while p-coumaric acid decreased. In addition to vegetative growth, both treatments improved fruit yield and its quality parameters. Our results showed that Si and AMF acted in a synergistic manner and improved growth and biochemical parameters in strawberry plants. However, the mechanism for Si-mediated increase of mycorrhizal effectiveness is not known, thereby needing further elucidation.