Abstract

The beneficial role of silicon (Si) in the growth of some plants is linked to its uptake and accumulation inside their tissue. However, the optimum level of Si in the nutrient solution that can provide maximum benefits and its interaction with other elements is less understood. A study was conducted to evaluate the impact of different levels of soluble Si in nutrient solutions on the uptake and distribution of Si and other elements into different parts of zucchini and zinnia, and its effects on the growth of these two plants. Increasing the concentrations of Si in the nutrient solution increased the accumulation of Si (in leaves and roots) and potassium (in stem and petiole) and reduced calcium without affecting the levels of magnesium and phosphorus in different organs of both plants. Application of Si at 50 mg L^-1 resulted in maximal accumulations of P, Ca and Mg in both plants and increased their growth. However, the application of higher levels of Si caused stunting. For optimal benefits, application of Si at 50 to 100 mg L^-1 is recommended for these plants.

Key words: Accumulation, distribution, growth, silicon, uptake, zinnia, zucchini.