Silicon in the stress mitigation caused by the lack or excess of nitrogen in lettuce

Abstract

For the good yield of cultivated species, especially lettuce, which is one of the most important leafy vegetables for fresh consumption, one of the main factors that affect its performance in the field is the lack of adequate nutrition for the crop. Thus, the search for information about the unavailability or availability of nutrients for this species, considered sensitive, becomes an important practice to understand the dynamics in the response of the culture submitted to the presence or absence of some nutrients, as sought in our research using silicon. The objective was to evaluate the effects of silicon on lettuce grown in nutrient solution, under stress caused by the lack or excess of nitrogen. The experiment was conducted in a completely randomized design, in a 3x2 factorial scheme with three replications. The factors were forms of N (N-30% in the form of NO₃^-; N-100% in the form of NH₄⁺ and N-100% in the form of NO₃^-) in the presence and absence of silicon (56 mg Si L-1 ). Green color index, total fresh weight, commercial fresh weight, aerial and root dry weight, commercial index, stem length, head diameter, total number of leaves and number of commercial leaves were evaluated. Using 100% N in the form of NH4 + reduces the productivity of lettuce, showing that the total supply of N in ammoniacal form is toxic to the plant.