Manejo de recursos naturais para o uso sustentável: caracterização fisiológica de duas espécies da caatinga com potencial econômico

Abstract

Sustainable development means a change of posture based on the use of natural resources management appropriate forms assuming in response the environmental changes caused by man. Soon, the sustainable management of the Caatinga becomes an important factor with the use of production techniques and conservation especially in areas that suffer from frequent droughts. Thus, the objective of this study was to diagnose physiological mechanisms related to two native species from the Caatinga, to promotion of improvements aimed at the management of these natural resources in a sustainable way. For carrying out such research was required to develop a test which corresponded to the study addressing the influence of soil water suppression and subsequent rehydrated on physiological behavior of the seedlings of Erythrina velutina Willd. (mulungu) and Mimosa caesalpiniifolia Benth. (sabiá) grown in the greenhouse in the Physiology Laboratory of Federal Rural University of Pernambuco. The work was performed between the months of May to September 2014, where donated seeds were used by the reference Center for recovery of degraded areas of the Federal of Vale do São Francisco University. After one hundred and twelve days in acclimatization, the differentiation of treatments: control, without irrigation and rehydrated. After application of the treatments were evaluated gas exchange daily, until the observation of stomatal closure. When the plants were rehydrated once, until new scanning stomatal closure for evaluation of photosynthesis (A), transpiration (E), stomatal conductance (gs), leaf water potential (f) and the relative water content (TRA), in addition to certain concentrations of chlorophylls a, b and total. Reduction of gas exchange occurred with the extension of the stress, plants of thrush and mulungu, however, mulungu presented better resistance, withstanding the conditions of water stress in comparison to sabiá. The values of the leaf and potential of the TRA for the treatment rehydrated also were reduced compared with control plants, being this behavior observed in the two collections (4 hour). It was observed that the thrush has presented a similar response pattern to the photosynthetic pigments, being the smallest medium found in plants reirrigadas. The mulungu presented increase in chlorophyll a values both in the treatment without watering as in rehydrated, but decrease in chlorophyll b and total values compared to the control treatment. With respect to the degree of resilience of two species, the mulungu stands out in relation to tolerance to periods of water shortage.