Silicon supplements affect floricultural quality traits and elemental nutrient concentrations of greenhouse produced gerbera

In greenhouse production most floricultural crops are cultivated in soilless substrates with limited concentrations of the beneficial element silicon (Si). Inclusion of supplemental silicon in greenhouse production is reported to affect the quality of several herbaceous plants that accumulate Si in their tissue. The goals of this study were to evaluate the effects of different Si sources and concentrations on the floricultural quality traits, the Si accumulation in plant tissues and the leaf tissue concentrations of other elemental nutrients of greenhouse produced gerbera (Gerbera hybrid L. ‘Acapella’). Potassium silicate (KSiO3) substrate incorporation or weekly substrate drench, sodium silicate (NaSiO3) foliar application, and rice husk ash substrate incorporation were used as Si supplements. Gerbera plants supplemented with several Si source and rate combinations, particularly NaSiO3 foliar sprays, produced thicker flower peduncles, increased flower diameters, increased height, and flowered earlier than non-supplemented controls. Gerbera plants grown in Si-supplemented media all accumulated higher levels of silicon in leaf, peduncle and flower tissues than non-supplemented controls. Leaf concentrations of macronutrients, such as sulfur and potassium, and micronutrients such as, boron, copper, iron, and manganese, were slightly changed among Si-supplemented plants. Foliar sprays of NaSiO3 at a rate of 150 mg Si L−1 caused stem shortening and flower deformation. However, silicon supplements can improve the floricultural traits of greenhouse grown gerberas, but forms and rates of Si must be optimized.