Eficiência do sistema antioxidante em plantas jovens de Paricá (Schizolobium amazonicum Huber ex Ducke) submetidas à diferentes doses de níquel.

Abstract

Soil contamination by nickel (Ni) excess represents a high potential for danger in the agricultural sector, in addition to bringing imminent risks to ecosystems and human health. Phytoremediation is a technique that has been used to recover areas contaminated by different groups, especially metals, through the planned introduction of plants with regenerative behavior, such as Paricá – Schizolobium amazonicum Huber ex Ducke. Therefore, the objective of this work was to evaluate the effect of nickel doses on the antioxidant system of young plants from Paricá. The experiment was carried out in a greenhouse from July to September 2019. The experimental design adopted was a completely randomized design (DIC), with five treatments (0, 200, 400, 600, and 800 µM L-1 NiCl2), in six repetitions. Data were submitted to analysis of variance using the Tukey test (p<0.05). The results showed that from 400 µM L-1 on, there was damage to the roots and leaves of Paricá, evidencing the oxidative stress caused by heavy metal. The antioxidant defense system of S. amazonicum was activated mainly at high nickel concentrations as a response to alleviate the toxicity and harmful effects on plants. An increase was observed for all enzymes analyzed in the tissues at a probability of 95%. However, it was not enough to prevent damage, evidenced by the increase of 312.79% and 290.43% of the Maloaldehyde variable in the roots and leaves of Paricá, respectively. Therefore, it is concluded that the plant defense system was efficient in attenuating the toxic effects of reactive oxygen species (ROS) at different nickel concentrations.