Selênio como atenuador do efeito do cromo sobre a germinação, crescimento e metabolismo do carbono e nitrogênio em plântulas de Schizolobium parayba var. amazonicum Huber ex Ducke.

Abstract

Paricá (S. parayba var. Amazonicum Huber ex Ducke) is indicated for plantations and agroforestry systems, with the potential to recover degraded areas due to their rapid growth and production and seed dispersal capacity. Environmental contamination by heavy metals has been associated, in particular, with intense industrial and agricultural activity that in the long term may become irreversible, and chromium (Cr) is a metal with several polluting chemical forms with serious implications for the environment and human health. Recently, several studies have shown that, in plants, selenium (Se) exhibited protective effects against other heavy metals. The objective of the research was to evaluate the effect of selenium (Se) on germination, growth and biochemical metabolism in seedlings of paricá submitted to doses of chromium (Cr). The experiment had treatments of the concentrations of Cr: 0, 80, 160, 240 µM and Se: 0, 5, 10, 15 µM. The experimental design used was a completely randomized, factorial 4x4 with four replications and the seeds of paricá were supplied by Embrapa. The normality test used was the Shapiro-Wilk test and for the homogeneity test the Levene test was used, both at (p ≤ 0.05) submitted to analysis of variance (ANOVA) accompanied by Tukey test (P < 0.05). The concentrations of Cr and Se did not affect the germinative variables of the seeds, with the exception of the percentage of germination, with better response in the dose of Se 15 µM (83.50 ± 1.87%.) The increase in the concentrations of Se 5 µM, 10 µM and 15 µM had a negative effect on root length and root dry matter. However, Cr and Se were positively affected by growth in height of paricá seedlings, with better response in the doses of Cr 160 µM and Se 15 µM (24.5 ± 0.3 cm.) In biochemical metabolism, Cr and Se affected the production of organic solutes such as glycine-betaine, proline, total soluble amino acids, total soluble proteins and sucrose, in general, the concentrations of 5 and 10 µM, obtained better results as a possible stress attenuator by Cr. However, Se did not provide satisfactory responses as a stress reliever for Cr.