Mineral nutrition with silicon by foliar application in orchid hybrid acclimatization

Silicon types and concentration and their interactive effects on plantlet growth of orchid Hadrolaelia lobatta x Hadrolaelia purpurata were studied. The plantlets from in vitro seeds were maintained in greenhouse, with 70% brightness, in plastic pots (90 cm(3)) filled with charred peel rice. The plantlets were grown on silicon sources concentrations (0; 0.5; 1.0; and 2.0 mg L-1): sodium silicate (SS) and Supa Potassio (R) (SP) through foliar sprayings, in all possible combinations. After 8 months the transplant the leaves number, aerial part length, root number, largest root length, root fresh and dry mass were evaluated. With increase in sodium silicate concentrations, a decrease up to a certain point was verified for all the studied variables. Better results for development of orchid plants were verified in the absence of silicon sources.