Ecotoxicological effects of metals with different concentrations and types on the morphological and physiological performance of wheat

Abstract

Large amounts of heavy metals end up in the environment as a result of ever-increasing anthropogenic activities and economic development. At least two specific types of heavy metals occur in the soil sub-ecosystem in most regions of China, especially in farmland. The morphological and physiological performance of wheat play a vital role in its growth and development, but heavy metals, both occurring independently and combined, may affect wheat growth. Thus, this study examined different concentrations of two types of heavy metals (copper (Cu), lead (Pb), and Cu and Pb combined) on the morphological and physiological performance of wheat. The number of tillers, plant height, ground diameter, single-leaf fresh and dry weights, leaf thickness, single-plant fresh and dry weights, leaf chlorophyll and N contents, and plant peroxidase and catalase activities of wheat significantly decreased when treated with two types of heavy metals. Thus, the two types of heavy metals significantly reduced the morphological and physiological performance of wheat; the ecotoxicological effects of heavy metals on the morphological and physiological performance of wheat increased with increasing heavy metal concentrations, especially on the leaf chlorophyll and N contents of wheat. The ground diameter and single-plant fresh weight of wheat in the Pb treatment were significantly lower than those under the independent Cu treatment with same concentration. Thus, the Pb treatment exerted more toxic effects on the morphological performance of wheat than the independent Cu treatment. The ground diameter, single-leaf dry weight, leaf thickness, single-plant fresh weight, and plant proline content of wheat under the combined Cu and Pb were significantly lower than those in the Cu and/or the Pb treatments. The combined Cu and Pb treatments addressed synergistic effects on the morphological and physiological performance of wheat. Accordingly, the growth performance of wheat will be significantly reduced in the combined Cu and Pb treatments compared with the independent Cu or Pb treatments.

Keywords: Copper; Heavy metals; Lead; Morphological and physiological performance; Wheat.