Combined Effect of Zinc and Cadmium Levels on Root Antioxidative Responses in Three Different Zinc‐Efficient Wheat Genotypes

Abstract

This work was undertaken to investigate the effect of zinc (Zn) nutrition on root antioxidative responses to cadmium (Cd) toxicity of three wheat genotypes differing in Zn efficiency. A hydroponic experiment was carried out in which two bread wheat genotypes (Triticum aestivum L. cvs. ‘Rushan’ and ‘Cross’) and one durum wheat genotype (Triticum durum L. cv. Durum) were exposed to three Zn2+ (10−11.11, 10−9.11 and 10−8.81 μm) and two Cd2+ (10−11.21 and 10−10.2 μm) activity levels. ‘Durum’ showed the highest root sulfhydryl (‐SH) groups content and activity of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) and the lowest root membrane permeability among the studied wheat genotypes. In ‘Durum’, Zn nutrition increased root ‐SH groups concentration of seedlings in Cd‐free nutrient solution. In ‘Cross’, as Zn2+ activity increased from 10−11.11 to 10−9.11 μm, root ‐SH groups concentration was increased while decreased with increasing Zn2+ to 10−8.81 μm. Cadmium increased root membrane permeability at both 10−11.11 and 10−9.11 μm Zn2+ levels. Activity of CAT and APX increased in roots of ‘Durum’ plants exposed to Cd at Zn2+ = 10−9.11 μm and thereafter decreased with increasing Zn2+ activity. In contrast, CAT and APX activity in roots of ‘Cross’ and ‘Rushan’ genotypes exposed to Cd decreased by increasing Zn activity to 10−9.11 μm and then increased at Zn2+ = 10−8.81μm. The results showed an increase in activities of antioxidative enzymes in Cd‐treated plants, although this increase was dependent on the crop genotype and Zn levels in the media.

Cadmium minimization in wheat: A critical review

“…The lower level of Zn increased the activities of CAT and APX in Cd-stressed wheat roots while higher Zn decreased enzyme activities, but this increase was dependent on the crop genotype and Zn levels in the media (Sanaeiostovar et al, 2012). Decrease in Cd concentrations in durum wheat grains might be due to competitive inhibition of Cd loading into phloem sap by Zn as suggested by Cakmak et al, (2000a).…”

Soil, Site, and Management Factors Affecting Cadmium Concentrations in Cacao-Growing Soils

“…Blommaert [27] reported that the liming of the soil may mitigate the Cd uptake only if the subsoil layers are not rich in Cd. Appropriate mitigation strategies of Cd uptake on cacao trees are therefore needed, and additional studies are encouraged in the field rather than in controlled conditions [28]. In cacao plantations in South America, management factors such as the use of fertilizers, pesticides, irrigation, organic farming [29] and forestry, as well as plant biodiversity, have been related to the total Cd contents in cacao plantation soils [19] and cacao beans [22].…”

Deep Roots are Pivotal for Regulating Post‐Anthesis Leaf Senescence in Wheat (Triticum aestivum L.)

“…, Sanaeiostovar et al. ). The difference in activities of these antioxidant enzymes between root‐restricted plants and controls indicates that the deep roots have a high potential to scavenge ROS in response to environmental stresses.…”

“…, Sanaeiostovar et al. ). In wheat, topdressing N at the shooting stage could enhance root activity, increase SOD activity and decrease malondialdehyde (MDA) content, and root activity is positively correlated with leaf photosynthesis rates (r = 0.8006) (Wei et al.…”