The effect of silicon was evaluated on the performance of nine lettuce cvs, cultivated in the nutritive solution in hidroponic system NFT. The experiment was conducted in protected cultivation, from March to May 2003. The randomized complete blocks design 9x2 was used, with three replications. Two factors were studied: nine lettuce cultivar (Vera, Verônica, Elisa, Regina, Aurélia, Tainá, Lucy Brown, Uberlândia-10000 and Mimosa), and presence (1,5 mmol L-1) or absence of silicon (japanese "silica gel") in the nutritive solution with 20% of SiO2 and 80% of H2O. The head diameter, weight of dry and fresh matter of head and roots, the concentration of silicon in leaves and roots were analyzed. The lettuce plants which received silicon presented a lower weight in comparison to the ones cultivated in solution without silicon, although both reached commercial weight. The lettuce treated with silicon presented lower incidence of physiological anomalies such as tip burn. Therefore, the silicon may be a reliable alternative for hydroponics production of lettuce mainly when considering the new market tendencies for products with better appearance.
Lactuca sativa; gel silica; plant nutrition; hydroponics
