GALVÃO SOBRINHO, T.; http://lattes.cnpq.br/4813795153459426; GALVÃO SOBRINHO, Thiago.
Resumo:
Lettuce stands out as the most produced cultivar in a hydroponic system.
However, the accumulation of nitrate may make its commercialization unfeasible, making
it necessary to monitor the nitrate content accumulated in lettuce. In this type of
cultivation, most of the nitrogen is supplied in the form of nitrate, which can lead to the
accumulation of this ion in the vacuoles. Thus, the objective of this study was to evaluate
the accumulation of nitrate in cultivars of Lettuce Crespa Hidropônica. The experiment
was carried out in a greenhouse belonging to the Federal University of Campina Grande
(UFCG), Campina Grande-PB. The design was in randomized blocks in a 5 x 2 factorial
scheme, with the first factor being five doses of nitrate in the nutrient solution (N1=25;
N2=50%; N3=75; N4=100 and N5=125 %) and the second factor two lettuce cultivars
(Robusta and Bs 55) with three replications in two cultivation cycles. At 21 days after
transplanting the seedlings, growth and production variables and the determination of
nitrate concentration in fresh leaves were analyzed. It was observed that the fresh mass of
leaves for the first and second cropping cycles had a similar effect, so that for the first, the
125% dosage promoted a gain of 111 g, while the 25% dosage was 72.6 g. In the second
cycle, an increase was observed when the lettuce was cultivated in a solution with 25% of
nitrate (95.53 g) in relation to the cultivars. For the first and second cycles, the cultivar
Robusta has a lower accumulation of nitrate recommended for consumption when
compared to Bs 55, promoting an average percentage difference of 12.08%. For the second
cycle, a similar effect was observed, whereby the accumulation for cultivar Bs 55 was
1766.65 mg kg-1 and for Robusta it was 1357.10 mg kg-1, promoting an average
percentage difference of 23, 18%. The increase in nitrate dosages favors the development
of curly lettuce and the increase of its concentration in the fresh lettuce leaves.
