Distribution of cadmium in shoot and root tissues1

Maize and pea plants were treated with 0.0 (control), 0.01 or0.05 mM Cd in the growing medium for 11 d. Although the totalCd concentration was similar in shoot and root tissues of bothspecies, pea plants showed more severe toxic symptoms. The freshweight and percentage of water content of root and shoot decreasedconcomitantly to Cd supply. High Cd levels were found in thecell-wall fraction (Fraction I) and in Fraction IV (soluble)of maize plants, whereas Cd-treated pea accumulated more Cdin the soluble fraction. The protein concentration of FractionIV of pea shoot and root significantly increased upon treatmentwith 0.05 mM Cd, whereas maize showed no effect. Furthermore,a previously not visible protein ({small tilde}12 kDa), appearedin Fraction IV of pea root grown with the highest Cd supply.Cadmium treatment, in general, notably enhanced the concentrationsof 2-thiobarbituric acid reactive material (lipid peroxidationproducts) in pea fractions, presumably due to Cd-induced oxidativestress. Key words: Cadmium sensitivity, tissue fractions, stress, Pisum sativum, Zea mays