Numerous data from a number of sources have demonstrated that different cultivars of the same plant show differences in their Cd absorption characteristics. Different plant parts (leaves, stems, roots) accumulate different amounts of Cd (SCOPE 31:141, 1987).
Concentration of Cd in soils varied widely. Elevated values of 10mg/kg soil or more were found.
During 1991 (MNL66:61, 1992) and 1992 we have studied some characters during germination of maize grains in controlled conditions without soil to assess the comparative behaviour of the progeny and the progenitors treated with elevated amounts of Cd. As in 1991, we have employed two flint type inbred lines, SC66 and SC75, and the hybrid SC66 x SC75. Grains of similar weight (244.5mg) were individually put into vials with cotton-wool and 2ml of distilled water with 0, 44.5 or 89µM of Cd2+ (as Cl-) and were grown at 28 C.
Relative mean Cd concentrations (µg Cd g DW-1) and dry matter diminution obtained in seedlings, 10 days after germination, presented the same tendencies observed in 1991: Cd concentrations among the various plant parts mark the pre-eminence in the roots in relation to grains or aerial parts; SC75 showed lesser DM diminution in relation to SC66 or the hybrid. We measured the absolute Cd uptake (µg cadmium into each tissue) (Table 1).
Table 1. Absolute Cd uptake (µg) 10 days after germination. Control:
no Cd. N=5. For each parameter (root, grain, aerial parts, total DM) means
with the same letter are not statistically different (P=0.05).
|Treatments||Root||Grain||Aerial parts||Total DM||Genotype|
|6.70bc||5.74d||5.54b||17.98bc||SC66 x SC75|
|11.72a||13.62a||7.44a||32.78a||SC66 x SC75|
Absolute Cd uptake was directly related to Cd concentration in the medium. Cd uptake by the hybrid was greater than Cd uptake by SC66.
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