Crescimento in vitro de Pogostemon cablin sob intensidades luminosas e leds

Abstract

Pogostemon cablin (Blanco) Benth, commonly known as patchouli, is an aromatic species of great commercial value, especially for perfumeries, due to the essential oil extracted from its leaves. However, the propagation of this species under field conditions suffers losses due to the incidence of diseases and to the lack of knowledge of technical factors that affect its cultivation. Therefore, tissue culture is a technique that can benefit the production chain of this species. However, for its application on plant propagation, it is necessary to adapt factors such as cultivation medium, light regime, light quality and intensity, etc. With this work, we aimed at evaluating the influence of light quality and intensity over the growth of patchouli plantlets cultivated in vitro, submitted to different intensities and light spectrums. The explants were cultivated under the light intensities of 28, 51, 64, 76 and 113 µmol m -2 s -1 , with four replicates each. For light quality, we used LED lamps, with six treatments in the colors white, red, blue, blue and red (1:3), blue and red (3:1), and blue and red (1:1), with four replicates. After 40 days, growth and photosynthetic pigment analyses were performed. The results showed that light intensity and quality influenced the growth of P. cablin. The treatment with 76 µmol m -2 s -1 obtained the best results for number of leaves, root length, root dry biomass and total dry biomass. For the photosynthetic pigments, the highest contents were verified with 51 µmol m -2 s -1 . The LEDs in the combinations of blue and red (1:3) and white spectrums obtained the best growth values. It is necessary to evaluate the influence of this light regime over volatile chemical composition of plantlets cultivated in vitro and acclimatized in order to establish a micropropagation method for this species.