Influence of foliar treatment with silicon contained in the Actisil Hydro Plus preparation on the growth, flowering and chemical composition of Gazania rigens (L.) Gaertn., Salvia farinacea Benth and Verbena hybrida Voss

Silicon is an element that significantly reduces the vulnerability of plants to biotic and abiotic stress factors, increases their resistance to pathogens and pests, strengthens tissues and cellular membranes, increases biomass and crops, improves the nutritional state of plants and increases the chlorophyll content. It also influences the formation of morphological traits of plants. The aim of our research was to determine the influence of silicon contained in the Actisil preparation on the growth and blooming of Gazania rigens, Salvia farinacea and Verbena hybrida, which are commonly cultivated in flowerbeds and on balconies. A two-factor experiment consisted of the foliar application of a solution of silicon in the following concentrations: 0 mg dm-3, 120 mg dm-3 and 240 mg dm-3. The application was performed 2, 4 and 6 times at one-week intervals. Biometric measurements were carried out at the beginning of the blooming of plants. The laboratory analyses included determinations of P, K, Mg, Ca, Si and the chlorophyll content in leaves. Beneficial influence of silicon on most of the morphological traits of the analysed species was demonstrated. Plants responded the best to two or four treatments with the silicon solution of a concentration of 120 mg dm-3, with an increase in the values of the analysed morphological traits. The application of silicon did not significantly modify the content of mineral elements in the dry weight of leaves. The application of silicon to Gazania rigens led to an increase in the content of this element in leaves as well as to an elevated chlorophyll content.