Effects of light intensity on the morphology and CAM photosynthesis of Vanilla planifolia Andrews

摘要: Vanilla planifolia is a neotropical orchid, whose fruits produce the natural vanilla, fundamental ingredient for food and cosmetic industry. Because of its importance in world market, it cultivated many tropical countries recently cultivation has started Colombia. This species requires shade development; however, optimal light conditions are unknown. work evaluates effect different intensities on CAM photosynthesis, physiology, morphology, growth this species. For this, vanilla seedlings were subjected to four treatments relative illumination (RI) (T1=8%, T2=17%, T3=31% T4=67%). Most CO2 assimilation occurred along night all treatments, which confirms that strong Plants grown under high lighting (67% RI) had almost half photosynthesis intermediate (17 31%), consistent with lower nocturnal acid accumulation treatment. Likewise, photochemical efficiency photosystem II (Fv / Fm) showed plants 67% RI radiation stress. On other hand, reached greater length, leaf area, total biomass when 31% RI). These results suggest alters functioning plants, inhibiting growth, highly shaded environments not significantly affected vanilla; long-term higher levels