Fotossíntese de plantas jovens de andiroba carapa guianesis aubl. e pau-de-balsa ochroma pyramidale (cav. ex lam.) urban submetidas ao déficit hídrico e a reidratação

Abstract

Studying how adaptations of plant species to disturbances have been a fundamental tool of plant ecophysiology. Much work has been done in the Amazon region to understand its mechanisms of adaptation of native species, as these are of great importance for degraded area recovery programs, due to their great potential to balance the flora and fauna of an area. until its vegetation is reestablished. Among these species are balsa and andiroba and are species that are often planted in consortia. The objective of this work was to analyze the photosynthetic performance of Guyana balsa wood and pyramid tick and carapa seedlings submitted to water deficit, where they were divided in two cases under irrigated and non-irrigated conditions and rehydrated to permanent photosynthetic levels a. zero. The experiment was carried out at the Amazonas State University - UEA, at the Norma Superior School - ENS, associated with the Institution's General Ecology Laboratory and in the greenhouse. They were performed as allometric analyzes, biomass allocation and photosynthesis measurements throughout the experiment. Both species had their photosynthetic performance soon reduced due to water stress, one species Ocrhoma pyramidale shows average net photosynthesis 0.5 μmol m-2 s-1 after 12 days, while andiroba has an average of -0.4 μmol m - 2 s-1 in 10 days. However, as species can quickly recover the photograph, when rehydrated, they present higher values than the control group. A biomass of both species for the non-irrigated group was always lower than the irrigated group. As growth medium in height and diameter of species as little varied species, however, there was an increase in leaf gain after stress, especially for a species of carapaíta, recorded its strategy and recovery by rapidly throwing new leaves at the end of water stress. Given the above, it can be concluded that O. pyramidale was more tolerant to water deficit than C. guianensis, but was able to quickly recover great plasticity. Keywords: water stress, plant ecophysiology, agroforestry systems, photosynthetic performance