Mercury phytotoxicity in common beans in soils of Minas Gerais, Brazil

Abstract

Problems caused by contaminated areas have been increasingly found around the world. Mercury (Hg) is a trace element potentially toxic to humans and the environment. Thus, monitoring Hg levels in the environment has great importance. The transfer of trace elements from soils to plants is a complex process, that depends on soil attributes such as pH, cation exchange capacity, texture, and mineralogy and also plant attributes, such as root system lenght and others. In Brazil, agricultural areas with levels of Hg higher than 12 mg kg-1 are considered contaminated, since such levels of Hg are likely to come from non-natural sources.

The State of Minas Gerais is the third largest producer of common beans in Brazil (2015/2016 farming year). The area planted with common beans is estimated in 339,000 hectares. The soil most used for such crop in the State of Minas Gerais is classified as Latosol (Oxisol).

The plants of Phaseolus vulgaris L. cv. BRSMG Madrepérola have indeterminate growth habit, low tolerance to lodging, and can be classified as an early-season variety. This variety has high yield potential and resistance to diseases, such as the common mosaic virose and anthracnose. P. vulgaris is one of the preferred plant species for using in ecotoxicological tests to evaluate the potential effect of toxic substances. The objective of this work was to evaluate the emergence and early development of common bean variety BRSMG Madrepérola under doses of mercury chloride (HgCl2), in two Latosols (Oxisols).