اثر مصرف توام كادميوم و روي در خاك آهكي بر پاسخ هاي گياه گندم

Effects of Combined Application of Cadmium and Zinc in Calcareous Soil on Responses of Wheat Plant

Cadmium (Cd) is a toxic element in plant nutrition and considered as a contaminant of food and feed. High levels of Cd in edible parts of crops such as wheat and rice grain are very dangerous as regards public health. Maximum tolerance level concentration (MPC) of Cd in wheat grain is 0.10-0.12 mgkg"1. A greenhouse experiment was carried out to examine the effects of combined application of Cd and Zn on responses of wheat plant on a calcareous soil of Karaj, In a factorial experiment with randomized complete block design CRCBD) and three replicates per treatment, five levels of Cd (0, 2.5, 5, 10 and 20 mgkg) and four levels of Zn (0, 10, 20 and 40 mgkg^-1) were added to the pot, then seeds of Mahdavi variety of wheat (Triticwn aeslivum L.) planted. The ANOVA results showed that Cd application significantly (P<0.01) decreased grain, straw, and total yield but Zn application increased these parameters significantly (P< 0.01). Application of Cd alone decreased the grain yield by 54.26%. while with Zn application the decrease in yield was 14,42%. The effects of Cd*Zn interaction were negatively significant. Cd increased the Cd concentration and uptake by grain and straw as well as total uptake but Zn application decreased the above parameters. Cd concentration in straw was higher than that in grain, but in the case of Zn it was vice verca. Applications of Zn decreased total uptake of Cd from 26.12 miu g pot-l in Zn0 to 11.26 miu g pot-1 in Zn3. Concentrations of Fe, Mn and Cu in grain were decreased when Cd and Zn were applied. For reduction of Cd concentration in wheat grain, application of Zn and P fertilizers, only on the basis of soil test, and a selection of wheat varieties with lower potential of Cd accumulation in grain are recommended.