Melissa officinalis L.: cultivo com água magnetizada, reguladores de crescimento e elicitores afetam a produção de óleo essencial

Abstract

Melissa officinalis L. (Lamiaceae) is an aromatic medicinal plant with high economic potential for the pharmaceutical, food and cosmetics industries, due to its wide applicability. The citral constituent present in its essential oil and the rosmarinic acid present in the extract of its leaves stand out in this species, for their biological activities. However, cultivation conditions can affect the quality and quantity of the final product of this species. Thus, three experiments were carried out to evaluate the effect of different levels of magnetized water, elicitors and growth regulators on the production of dry matter and on the quantitative and qualitative characteristics of the essential oil of Melissa officinalis L. To evaluate the effect of magnetized water, used a completely randomized design, in a 2 x 4 factorial scheme, with two types of water (magnetized and non-magnetized) and four levels of irrigation 25, 75, 100 and 125% of crop evapotranspiration (ETc) and 4 repetitions. To evaluate the effect of growth regulators, a completely randomized design was used, in a factorial scheme with an additional treatment (3x3 + 1), with 4 repetitions, with three levels of growth regulators ANA (naphthalene acetic acid), BAP ( benzylaminopurine), GA3 (gibberellic acid), and four levels of concentrations (0, 25, 50 and 100 mg L-1), plus additional treatment (distilled water + Tween 80). To evaluate the effect of the elicitors methyl jasmonate (MJ), salicylic acid (AS) and chitosan (QT), a completely randomized design with different concentrations of MJ (0, 0.5, 2 and 8 mM), AS (0 , 0.25, 0.5 and 1.0 mM) and QT (0, 2, 4 and 6 g L-1 ). The experiments with magnetized water and elicitors were the ones that most significantly affected the accumulation of dry matter, photosynthetic pigments, the content of total phenols and soluble proteins, and the yield and concentration of the citral (neral + geranial) and citronellal constituents of the essential oil. In the experiment with growth regulators, BAP and GA3 were the ones that most favored these variables compared to ANA, being only inferior to the control treatment. Thus, the application of irrigation techniques with magnetized water and leaf spraying of elicitors are favorable in the agricultural production of M. officinalis.