Aluminum interference on radicular growth, absorption and phosphor accumulation in paricá plants

Abstract

The species Schizolobium amazonicum Huber ex. Ducke (paricá) is a native species planted for large-scale timber production. The good development of the species depends on factors such as tolerance to levels of some plant toxic elements, such as aluminum (Al³⁺), and nutrient in appropriate concentrations, such as phosphorus (P). Thus, the objective of this study was to analyze the effect of aluminum on phosphorus absorption and translocation and the presence of these elements in the roots of Schizolobium amazonicum Huber ex. Ducke grown in nutrient solution. The study was conducted in a greenhouse of the Institute of Agrarian Sciences of the Federal Rural University of Amazonia (Belém-PA). The treatments consisted of two aluminum concentrations: 0 and 20 mg L^-1, applied to the nutrient solution, consisting of: 97 mgL^-1 H₂PO^-4. Phosphorus (P) and aluminum (Al) accumulation in the roots and shoots were determined to evaluate the influence of plant phytotoxicity. In addition, qualitative and quantitative analyzes of the two elements were performed in the root tissues, where the presence and percentage of the elements in the epidermis, cortex and central cylinder were observed through dispersive energy spectrometry (EDS) analyzes. The dry matter, phosphorus accumulation and aluminum data were submitted to the T test at 1% probability in the Bioestat 5.0 program. Descriptive statistics (means and percentages) were also calculated for the spectrometric analysis variables. The plants treated with Al presented low dry matter production in the shoot, while in the root it was observed great gains of matter. P and Al tended to accumulate in the roots, being poorly translocated to the shoot. Aluminum impaired the translocation of phosphorus to the aerial part of the paricá plants. P was more in the cortex and aluminum in the epidermis of the roots.