Análise dos transientes da fluorescência da clorofila a de plantas jovens de Carapa guianensis e de Dipteryx odorata submetidas a dois ambientes de luz

tropical tree species are almost always under high irradiance in the amazonian. the high energy flux can be decisive for the success or not in the initial establishment in the field. the objective of this study was to investigate the answers of young plants of andiroba (carapa guianensis aubl) and cumaru (dipteryx odorata (aublet) willd) exposed to two light environments (shade and sunlight). the experiment was carried in manaus-am, brazil (3o8's, 59o52'w). analysis of chlorophyll a fluorescence transients were obtained in intact and healthy leaves between 10:00 to 12:00 am. the curve ojip indicated that the species high irradiance exposed presented photoinhibition after 45 days of experiment. andiroba and cumaru plants exposed to sunlight exhibited low values of tro/abs (7.17 and 20.4%, respectively), eto/tro (14.5 and 27.2%, respectively) and eto/abs (20.6 and 42.2%, respectively) and high values of dio/abs (26.9 and 43.0%, respectively), compared with plants exposed to the shadow with 45 days of experiment. as for phenomenological flux, most of the parameters, low values were observed for both exposed species in the sunlight. andiroba and cumaru plants exposed in the sunlight exhibited low values of piabs (63.3 and 78.7%, respectively) compared with exposed plants to the shadow at the end of the experiment. although the species have suffered with the stress for high irradiance andiroba specie presented better performance than cumaru being indicated for use in production planting or degraded area restoration.