Crescimento, alterações ecofisiológicas e bioquimícas em plantas jovens de jatobá (Hymenaea courbaril L) submetidas à deficiência hídrica e ao alagamento

Abstract

Jatobá is a Neotropical tree that has economical, ecological and environmental importance. Several research demonstrate that this species can be extracted many substances, besides it to have potential to uses in commercial and agroforestry reforestations. Excess or deficit in water supply to plant can promote metabolic changes and consequently to modify your growth. Plants when exposed to stress response through several defense mechanisms. Tolerance to dehydration is linked to substances called by osmoregulators such as carbohydrates, proline, glycine betaine, free amino acids, which will have function to keep water by the more time possible into plant tissue Based in this information, this study haves aim to evaluate growth, eco physiological changes, and biochemical in Jatobá young plants subjected to water deficiency and flooding. Experiment was conducted in greenhouse environment located in Instituto de Ciências Agrárias (ICA) of Universidade Federal Rural da Amazônia (UFRA), in Belém city, PA, Brasil Experiment period was between 20/09/2008 to 20/05/2009. Jatobá young plants (H. courbaril L.), with 4 months of age, propagated via sexual, from seeds harvested in petroliferous province of Rio Urucu, operational base Geólogo “Pedro de Moura' in Urucu, Coari city, AM, distance of 650 Km, in line, of Manaus city. Seeds were harvested in November of 2008, in areas of 20 extraction field: RUCO6, RUC10, JAZ5, JAZ16, RUC 31; RUC 25; JAZ 97; JAZ 06; JAZ 16; JAZ 21; CL 10; CL 33; CL 11; CL 05; CL 04: SUC 03; SUC 02; SUC 01; LUC 29; LUC 39. After harvest, seeds were placed in paper bags hermetically closed and transported to laboratory of Fisiologia Vegetal of UFRA, Belém, PA. Plants were subjected to three water regimes (control, water deficit, and flooding), that were applied 30 days under water deprivation and flooding through a water lamina of 5 cm up soil, respectively. Design experimental was entirely randomized with three water conditions (control, water deficit, and flooding), with 15 replicates, totalizing 45 experimental units, each experimental unit was composed by one plant per pot. In results were applied variance analysis and average compared by the Tukey test in 5% significance level. Biochemical and ecophysiological variables were investigated, which present influence on vegetative growth of Jatobá plants. Water deficit and flooding provoke reduction in key enzyme activities related to nitrogen metabolism and changes in dehydrogenase alcohol and dehydrogenase lactate. Besides of this, water stress also changed behavior of nitrogen compounds such as amino acids, proteins, ammonium, producing osmoregulator substances as proline, glycine betaine, carbohydrates, and sucrose. Water deficit and flooding affected plant development, being demonstrated in height, stem diameter, dry matter production Water deficit and flooding applied act in water relations, reducing significantly leaf water potential, and these are highly correlated. During period under water deficit and flooding were showed significant decreases in transpiration, and consequent increase in diffusive resistance. Also were showed significant increases in organic solute levels, in agreement with treatment severity, being proline the organic solute that presented higher sensibility to water deprivation. Jatobá young plants paralyze not your growth when cultivated with low water available in soil during initial phase of development. This species studded is few susceptible to flooding, if compared to water deficit, because without water it presented adequate osmotic adjustment process, although these results are not sufficient to testes in study of forestry specie under environment effects