Cu, Zn and Cd uptake of three corn hybrids grown in a heavy metal-contaminated soil

The aim was to evaluate the shoot and root growth and the uptake of Cd, Zn ad Cu by three different corn hybrids (single cross 9 = SC 9; 3-way-cross 3052 = 3-WC 3052, double cross Amoun = DC Amoun) grown in a heavy metal contaminated soil (Loess loam, pH CaCl2: 6,9. aqua regia soluble in ppm: Zn: 1293, Cd: 24, Cu: 128) for 8 and 16 days in a growth chamber. The hybrids resulting from 3 or 4 inbred lines showed significantly higher shoot and root dry matter (+ 45 %/+ 79 %), root length (+ 113 %) and a higher root length to shoot weight ratio (+ 48 %) compared to the hybrid out of 2 inbred lines. The total Zn and Cd intake by shoot of the multiple cross plants was significantly higher than the intake by single cross plants (Zn: + 82 %, Cd: + 44 %), but there was no statistical difference between the 3 genotypes for Cu. In spite of the higher Zn and Cd uptake into the shoot (69 %, 31 % resp.) there was no significant increase of the Zn and Cd concentration in the shoots of the multiple crossed hybrids. This could be a result of (a) reduced concentration of the metals by the increased shoot growth, (b) a lower Zn and Cd influx in the root. This example shows that it is possible by using conventional breeding methods, to increase the shoot growth and keep the Cd concentration into the product at a low level.