Genotypic differences in uptake and translocation of cadmium in bean and maize inbred lines

Abstract

For better understanding of mechanisms responsible for genotypic differences in uptake and translocation of cadmium (Cd) in different plant species, two maize (Zea mays L.) inbred lines (B37 and F2) and a bean (Phaseolus vulgaris L.) cultivar (Saxa) were grown in a complete nutrient solution with additional 0.5 μM Cd and 250 μM buthionine sulfoximine (BSO), an inhibitor of PC synthesis, alone or in combination. The maize line B37 had a much higher Cd content in shoots (116.2 mg Cd kg−1 dry wt.) than F2 (32.7 mg Cd kg−1 dry wt.) and bean (1.83 in leaves, and 2.85 mg Cd kg−1 dry wt. in stems), whereas in roots the Cd content was much higher in bean (602.6 mg Cd kg−1 dry wt.) than in maize (427.1 mg Cd kg−1 dry wt. in B37, and 428.2 mg Cd kg−1 dry wt. in F2). Application of BSO markedly decreased Cd contents in roots of bean and maize lines, and also Cd contents in shoots and stem basis of both maize lines, while Cd contents in leaves, stems and stem basis of bean were not reduced by BSO.In root extracts (Tris‐HCl buffer, pH 8.0) the proportion of Cd in the soluble fraction was much lower in bean (29.6%) than in the maize lines B37 (58.6%) and F2 (60.1%). Compared with the whole root tissue, Cd contents in the stele of the roots were much lower, especially in bean, and decreased by BSO in both maize lines, but not in bean.Gel‐chromatography of root extracts strongly suggested that in the soluble fraction about 80% of the Cd was present as Cd‐phytochelatin (PC) complexes in B37, whereas in F2 this Cd fraction accounted for about 50%, and in bean only for a few percent in the soluble fraction, Our results suggest that Cd‐PC complexes constitute a mobile form in plants. The lower proportion of Cd in the soluble fraction as well as lower PC production in roots of bean compared to maize lines may be the main reasons for the very low Cd translocation from roots to shoots in bean plants.

Growth and cadmium accumulation in selected switchgrass cultivars

“…Plants readily absorb Cd, but tolerance to Cd and distribution of Cd among plant organs varies among species (Haghiri, 1973;Page et al, 1972) and genotypes (Cieslinski et al, 1996b;Guo and Marschner, 1996). There is a large difference among plant species in absorption and distribution of Cd within the plant (Harrington et al, 1996).…”

Cadmium retention in rice roots is influenced by cadmium availability, chelation and translocation

“…Although this metal is not essential for plant nutrition, it can be easily taken up by roots and accumulated in vegetative and reproductive plant organs. In this way, Cd‐rich soils potentially result in Cd‐rich foods, although natural variation occurs in both the uptake and the distribution of Cd in crop species (Guo, Schulz & Marschner 1995; Grant et al . 1998; Cakmak et al .…”

Genetic Control of Cadmium Concentration in Soybean Seeds

“…Lines with the low Cd trait had restricted root-to-shoot translocation, which limited the Cd accumulation in the grain. Genetic variability in soybean [2,22,23,25,51,54] has been reported.…”