Nitrogen Metabolism, Carbohydrates and Sucrose in Young Plants of Paricá (<i>Schizolobium amazonicum</i>) Submitted to Different Dosages of Aluminum

Abstract

The paricá [ Schizolobium amazonicum Huber ex Ducke] is a native species of the Amazon region, belonging to the Fabaceae family and is a legume that has great social and economic importance, raw material for the manufacture of wood panels. Heliophilous, with wood of light density and good workability. Amazonian soils are highly weathered and characterized by high acidity, so Al harms the growth and development of sensitive plants, as well as the presence of resistant and/or tolerant plants. Thus, in this work, we sought to study the biochemical metabolism alterations generated in young plants of Schizolobium amazonicum Huber ex Ducke affected at different dosages of AlCl 3 . The research was conducted in a greenhouse of the Federal Rural University of Amazonia, using pre-scarified paricá seeds, which were seeded in plastic containers of 3.5 L capacity, with black soil fertilized with NPK 15-15-20. On the 8th day after sowing (DAS), thinning of 5 seedlings was performed for 2, and on day 12 of 2 for 1 seedling. The treatments started after 1 month and 22 days of sowing and the plants were collected 24 days later. A completely randomized experimental design (RED) was used, with 6 treatments (Control, Al 15 mg/L -1 , Al 30 mg/L -1 , Al 45 mg/L -1 , Al 60 mg/L -1 and Al 75 mg/L -1 ) with 5 replicates each (one plant/pot) totaling 30 experimental units. The AlCl 3 dosages resulted in considerable changes in the biochemical variables evaluated, especially when the 75 mg &middot; L -1 dosage was applied. The considerable reduction in some variables such as nitrate reductase, glycine betaine and total soluble carbohydrates of these compounds to the applied AlCl 3 &middot;6H 2 O dosages, is a way to create resistance mechanisms to try to overcome stress or as a way of showing limitations in the applied dosages. The species was sensitive to the AlCl 3 dosages, and resisted only 23 days to the imposed stress. However, it presented defense mechanisms that were able to prolong the physiological activities ; since without them, the time of exposure to the stress would possibly be less.