Interação entre fungos micorrízicos arbusculares e mudas de Jatobá (Hymenaea courbaril L.) submetidas ao déficit hídrico

Abstract

The native species Hymenaea courbaril L. (Jatobá) has a wide occurrence in the Amazon, its wood is appreciated by the timber industry and by traditional peoples and communities that use the bark, fruits, seeds, sap and leaves as medicines. However, climatic factors, such as longer and more frequent dry periods, are possible threats to the initial development of this species. However, several studies demonstrate that the symbiotic relationship between Arbuscular Mycorrhizal Fungi (AMF) and plants promotes an increase in plant tolerance to different stresses, such as water deficit. The research aims to evaluate physiological and biochemical parameters of Hymenaea courbaril L. seedlings inoculated with AMF in different water regimes. The study was carried out in the forestry nursery of the Federal University of Western Pará (UFOPA) in the Santana Unit. The seeds were placed to germinate in tubes containing commercial substrate and placed to germinate in 70% shade in the nursery. The seedlings were transplanted into 5-liter pots and filled with autoclaved commercial substrate. The treatments consisted of: 1. ideal irrigation condition (80% of field capacity), 2. moderate water deficit (50% of field capacity) and 3. severe water deficit (25% of field capacity); in the presence and absence of the FMA; totaling 6 treatments, 8 replications and 48 pots. In this way, half of the pots were inoculated with AMF, and the other half were not. Analyzes of growth, height, stem diameter, number of leaves, leaf area, root length, root volume were carried out; in addition to analyzes on symbiosis such as spore density, percentage of root colonization, as well as physiological and biochemical analyses. The collected data were subjected to the Shapiro-Wilk test and the means grouped using the Tukey test at 5% probability. The H. courbaril seedlings showed changes in growth and biochemical metabolism in the presence of AMF, the concentrations of chlorophylls and carotenoids were not influenced, and the fungi promote benefits in growth, nutrition and carbohydrate reserves in the plant, proving that mycorrhizae can be used to increase the tolerance of Jatobá plants under water deficit. It is concluded that plants with mycorrhizae have greater initial growth, better phosphorus absorption, a tendency to increase carbohydrate reserves and osmoregulation can be controlled by proline and amino acids.