Silício como mitigador da toxicidade de zinco em plantas jovens de Schizolobium amazonicum Huber ex Ducke

Abstract

Zinc is an essential element for plants, however, in excess it can be toxic to plants. Phytoremediation of soil contaminated by Zn is effective in reducing the toxic effects of this metal on the environment. Therefore, it is necessary to identify species tolerant to these conditions. Schizolobium amazonicum is a tree species native to the Amazon used to recover degraded areas. Silicon is a beneficial element that increases the plant's tolerance to biotic and abiotic stresses. Therefore, the objective of this work was to evaluate the effects of silicon on growth, nutritional status and physiology of young plants of S. amazonicum submitted to toxic levels of zinc. A randomized block design was used in a 4 x 2 factorial scheme, with four concentrations of zinc (1, 150, 300 and 600 µM) and two concentrations of silicon (0 and 1.5 mM) with five repetitions for 30 days. Nutritional status, growth, chlorophyll a fluorescence, gas exchange and photosynthetic pigment content in seedlings were evaluated. The results showed that the high levels of zinc reduced plant growth, the absorption of evaluated nutrients and photosynthesis, with effects mainly associated with the photochemical limitation and the reduction in the capacity of CO2 fixation in the mesophile, however, the application of Si attenuated this It is made. S. Amazonicum showed low translocation and moderate and high tolerance to Zn concentrations, indicating that this species can be used as a phytostabilizer of this metal.