Influência da qualidade de luz no crescimento e acúmulo de voláteis de Mentha spicata cultivada in vitro

Abstract

The objective of this study was to investigate the influence of light quality on the growth and accumulation of volatile constituents of Mentha spicata grown in vitro. Nodal segments of already established plantlets were maintained under fluorescent lamps and light-emitting diodes (LEDs) with spectral regions in green, yellow, red, blue, and white, and in the combinations between red and blue (1:1; 2:2, and 2:1). After 45 days, growth parameters, leaf area, growth index, photosynthetic pigments, and analysis of the volatile chemical composition of leaves by headspace-CG/FID were evaluated. The 1:2 combinations provided larger leaf, root, and total dry weight. Green, yellow, fluorescent, and red plantlets presented characteristics of etiolation. In relation to the volatile chemical composition, the major constituents α-pinene, sabinene, β-pinene, myrcene, 1,8-cineol, and carvone were identified. Plantlets grown under green and yellow LEDs resulted in greater accumulation of carvone. Thus, this study contributed to the understanding of the changes caused by light quality in vitro growth and in the volatile chemical composition of mint. It is concluded that the micropropagation of Mentha spicata under LEDs in the combination of red and blue 1: 2 is the most favorable for growth and content of carvone and 1,8-cineol.