Effect of increasing atmospheric CO2 concentration and cadmium on the uptake of iron, copper and zinc in wheat and sorghum

Climate change, especially an increase in CO2 concentration and soil pollution due to heavy metals, has changed plant growth and metal uptake by them. This research was carried out in order to investigate the impacts of increasing atmospheric CO2 concentrations on Fe, Cu and Zn uptake and the growth parameters of wheat and sorghum at two levels of CO2 (400 and 900 μL L-1) and four levels of cadmium (0. 10, 2 and 40 mg kg-1). After 60 days, the plants were harvested, and the results showed that increasing CO2 concentration led to significantly increased plant height, leaf area, root and shoot dry weight (p< 0.01). Increasing CO2 concentration caused increase concentration and uptake of Cd, Fe, Cu and Zn in sorghum shoot and root. In contrast, uptake of these elements in wheat decreased. Among nutrients, the greatest increase in concentration for shoots of sorghum was in Zn (14-25%) and in root was related to Fe (16-25%). For wheat, Cu showed the greatest decrease in concentration in shoot (19-25%) and root (10-15%). Decreasing the uptake of Cd in wheat can be a factor for higher stress tolerance but, on the other hand, a decrease in micronutrient concentrations, especially of Zn, in crops such as wheat that has been used widely, can create problems associated with plant growth conditions and food production. For sorghum, although an increase in the uptake of nutrients was seen, increased Cd uptake is a problem that must be noted within the context of human and food safety.