Multivariate Analysis Reveals Different Responses of Antioxidant Defense in Wheat Plants Exposed to Arsenic (As) and Cadmium (Cd)

Abstract

Background: Multivariate analysis is a chemometric tool that has been little explored to determine physiological status under heavy metal stress. Nevertheless, PCA has an unexplored potential to determine plant physiologic status and its modification under stress factors like “heavy metals”. Objectives: Present work aims to assess the physiological and biochemical effects and responses of wheat plants under different exposition of As and Cd using multivariate models. Material and methods: Wheat plants growing in greenhouse were exposed to 0, 10 and 50 mg Kg-1 soil of As and 0, 10 and 33 50 mg Kg-1 soil of Cd until growth stage 5. After 56 days, wheat leaves and roots were collected for determination of dry weight, lipid peroxidation and the enzymatic activity of catalase, ascorbate peroxidase and guaiacol peroxidase. These measures were considerate as variables of three performed multivariate models for determination of physiological status. Results: Through interpretation of Scores plot and Loading plots in combination, it was possible to determine that both As and Cd affect chlorophyll content as well as antioxidant response. However, decreasing of chlorophyll, increase of lipid peroxidation and inhibition of antioxidant response was more accentuate in wheat plants exposed to As than those exposed to Cd. Conclusions: Multivariate analysis allows to determine the differences between the physiological behavior of both stressor which turn this chemometric tool useful for characterization of a physiological response.