Vegetative development and production of essential oil of Patchouli under radiation levels and GA3 application

Pogostemon cablin Benth. has economical importance due to the essential oil which is used in the pharmaceutical and perfume industries. Among the environment factors, the radiation is extremely important for plant development and its limitation can result on decrease of yield. The application of gibberellins promotes the cellular elongation resulting on increase of plant height. Therefore, the radiation level and plant growth regulators can indirectly affect the essential oil production due its accumulation in the biomass. The objective of this work was to evaluate vegetative development and essential oil production of patchouli under shading and after GA(3) application. The experimental design was completely randomized in a 2 x 3 factorial arrangement comparing shading levels (0, 54, and 77%) with or without GA(3) application (200 mg.L-1). The GA(3) was applied 30 days after planting. The plants showed a superior height under 77% of shading and with GA(3) at 120 days after planting. The leaf number was superior on plants developed under no radiation limitation and after 75 days of GA(3) application. The stem number also was significantly superior under no shading and without GA(3). The application of the growth regulator at 75 days also promoted great stem number of branches with 54% of shading. However, treatment with GA(3) increased essential oil yield and productivity and greater yield in P. Cablin under shading conditions. The growth regulator can be used to compensate the negative effect of lower radiation levels. This is of great interest for patchouli cultivation as the GA(3) application allows to increase plant population and, consequently, biomass and essential oil production.