Silicon Supplied Via Roots or Leaves Relieves Potassium Deficiency in Maize Plants

Abstract

The aim of this study was to determine whether silicon (Si) supplied via nutrient solution or foliar spray is nutritionally and physiologically efficient in mitigating potassium (K) deficiency in maize plants. To that end, an experiment was conducted in a greenhouse with maize plants grown in a hydroponic system. The treatments included two levels of K, i.e. K deficient (0.2 mmol L−1 of K) and K-sufficient (6 mmol L−1 of K). Under both these conditions, Si was supplied through stabilized potassium sodium silicate via nutrient solution (2 mmol L−1 of Si) or foliar spray (5.3 mmol L−1 of Si) and control (0 mmol L−1 of Si), using a completely randomized design and four repetitions. Potassium deficiency without the addition of Si showed less accumulation of K and Si and lower levels of photosynthetic pigments. It also caused the reduction in gas exchange and, consequently, a reduction in vegetative development. However, Si relieved K-deficiency stress in maize plants, since it improved nutritional, physiological and growth variables. The application of Si to K-deficient maize plants improved their water use efficiency, their chlorophyll and carotenoid contents, and their dry matter production. This effect was more evident in the treatment of Si via roots.