Influência do sombreamento na produção de biomassa, óleo essencial e quantidade de tricomas glandulares em cidrão (Lippia citriodora Lam.)

Abstract

ResumoO objetivo do estudo foi verificar o efeito do sombreamento na produção de óleo essencial, biomassa e quantidade de tricomas glandulares em cidrão (Lippia citriodora Lam.) no Norte de Minas Gerais. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e cinco repetições. Os tratamentos consistiram em quatro níveis de radiação fotossinteticamente ativa (RFA) utilizando telas tipo sombrite que permitem a passagem de 25, 50, 70% de luz e a pleno sol (controle). Foram determinadas as variáveis: matéria seca da raiz, matéria seca da parte aérea, número de flores, matéria seca total, relação raiz/parte aérea, produção de óleo, teor de óleo essencial e quantidade de tricomas glandulares. Foram observadas diferenças estatisticamente significativas para massa seca da raiz, massa seca da parte aérea, número de flores, matéria seca total, razão raiz/ parte aérea, produção de óleo e quantidade de tricomas, todavia o mesmo não ocorreu para o teor de óleo. Os resultados evidenciaram que a pleno sol houve uma maior produção de biomassa que nos demais tratamentos e no sombreamento de 70% o número de tricomas foi maior. O teor de óleo não sofreu nenhuma alteração em relação aos tratamentos. AbstractInfluence of shade on the biomass and essential oil production of Lippia citriodora (Lam.), Brazil. This study aimed to evaluate the effect of shading on the production of essential oil and biomass in Lippia citriodora (Lam.) -known as cidrão -in the north of Minas Gerais, Brazil. The experimental design was Biotemas, 22 (4): 9-14, dezembro de 2009

Light affects Varronia curassavica essential oil yield by increasing trichomes frequency

“…Irradiance acts on the activation of biosynthetic pathways of essential oils, which are dependent on supply of carbon backbone obtained by photosynthetic processes, which are generally higher in enlightened environments (Schuh et al, 1997). Similarly to V. curassavica, Ocimum basilicum (Chang et al, 2008) and Lippia citriodora (Gomes et al, 2009) grown at different light intensities, also showed higher essential oil content when were grown under full sunlight. As the essential oil yield is a direct result of essential oil content and plant biomass (Costa et al, 2010), and no change in the leaf dry biomass production of V. curassavica was observed, the highest essential oil yield observed under high irradiance, can be attributed to the higher essential oil content found in these conditions.…”

“…In V. curassavica the essential oil is secreted and stored in glandular globular trichomes present on the leaf surface (Ventrella and Marinho, 2008), whose frequency and development can be influenced by irradiance (Gomes et al, 2009;Costa et al, 2010).…”

Growth Environment and Pot Volume Affect Biomass and Essential Oil Production of Basil1

“…Similarly, Chagas et al (2013) found that Mentha arvensis L. plants grown under 50% shade screens had changes in leaf and growth characteristics, denoting their phenotypical plasticity when they were grown in environments under different lights; the greater effect of light intensity than light quality on these plants; and that synthesis and accumulation of essential oil can occur under shaded, highly lit environments; however the plants in the treatments under shading had grater leaves with lower oil concentration. Gomes et al (2009) found that Lippia citriodora plants grown under full sun conditions had greater biomass production, and those under 70% shading had higher number of trichomes. Martins et al (2008) reported that the blue light contributed to a higher essential oil content in O. gratissimum plants grown under blue screen when compared to those grown under red screen or at full sun.…”

Biomass and morphological parameters of lemon verbena (Aloysia triphylla) under different shading levels during different seasonal conditions

“…Pinto et al (2007) studying Aloysia gratissima, observed a 25% reduction in dry matter in leaves which received 80% of shading in relation to full sunlight and 35% compared to 40% shading. Gomes et al (2009) studying Lippia citriodora, observed that the total dry matter in full sun was higher compared to the treatments under 50 and 25% total light.…”