Interações entre ferro e zinco em acessos de Pfaffia glomerata (spreng.) pedersen: parâmetros morfológicos, bioquímicos e fisiológicos

Abstract

Despite the natural occurrence of heavy metals in low concentrations in the soil, the increase in these concentrations caused mainly by anthropogenic activities such as the use of fertilizers and pesticides in agriculture, is extremely harmful and can cause damage to human and animal health by ingestion. Despite this, few studies have related the effects of the interaction between heavy metals, a situation of common occurrence in nature. In this study, the effects of the interaction between iron (Fe) and zinc (Zn) were studied with the aim of evaluating their influence on dry matter production, antioxidant system, photosynthetic parameters and root biometric parameters, as well as to classify Pfaffia glomerata (Spreng.) Pedersen according to their level of tolerance to Zn, Fe excess and their response to the interaction of these metals in hydroponic system. The treatments consisted of three levels of Fe (50, 700 and 1400 μM), three Zn levels (2, 200 and 400 μM) and three accessions of P. glomerata (GD, BRA and JB), totaling nine treatments. Ten plants of each access remained in cultivation for 21 days in contact with the nutrient solution. The three accessions presented a reduction of the dry mass of root shoot, both due to the excess of Fe and to the excess of Zn. Notably, the excess of Fe presented a greater impact in the reduction of the root parameters and in the increase in the lipid peroxidation of the three accessions in relation to the excess of Zn. However, it was possible to observe great variability between the accesses. BRA access was more sensitive to both Fe excess and Zn excess, with a reduction of approximately 90% in root length in the condition of Fe excess and no positive response to the interaction. The interaction between the high Fe and Zn levels was especially positive for the GD access, which even in the excess condition, was able to maintain the dry mass production and the robustness of the root system, suggesting the possibility of its use in areas of contamination.