Abstract

Phosphorus (P) deficiency is one of the major concerns that limit not only the yield, but also the quality and healthy properties of wheat produced in Southern Chile. Current evidence has shown that silicon (Si) can be envisaged as a sustainable alternative to enhance the tolerance to P deficiency of wheat. We investigated the effect of Si fertilization on phenols concentration, antioxidant activity, photosynthetic performance and yield of wheat (Triticum aestivum) growing at different P supply. A field assay by using wheat cv. Fritz was performed on an Andisol with low available P content never amended with Si fertilizers. Three P doses (0, 200 and 400 mg P kg-1 soil; as Triple superphosphate) were applied in combination with three Si doses (0, 250, 500 mg Si kg-1 soil; as Magnesil®). Three harvest periods corresponding at different growth stages (tillering, anthesis and mature grain) were evaluated. At tillering stage, reductions of total phenols, CO2 assimilation, stomatal conductance and transpiration were found in plants not fertilized with P. However, Si application increased phenol accumulation and photosynthetic parameters in tillers of wheat at either 0 or 200 mg kg-1 P added. An enhancement of antioxidant activity by about 20% was also induced by Si in plants cultivated at low availability of P in soil. At anthesis stage, although no changes in photosynthetic parameters among treatments were observed, increasing Si doses improved phenols concentration and antioxidant capacity as the dose of P supply augmented from 0 to 400 mg kg-1 P. Consequently, Si amendment enhanced grain yield in wheat irrespective of the P supplied. Acknowledgment: FONDECYT Project 1161326 and Dirección de Investigación of Universidad de La Frontera.