EFFECT OF VARIOUS METAL-IONS ON GROWTH OF 2 WHEAT LINES KNOWN TO DIFFER IN ALUMINUM TOLERANCE

The effects of aluminium (Al), manganese (Mn), zinc (Zn), copper (Cu), boron (B), iron (Fe), gallium (Gal, scandium (Sc) and lanthanum (La) on growth of an Al-tolerant and an Al-sensitive line of wheat (Triticu m aestivum L.) were measured in solution culture. The concentrations o f nutrients in the basal nutrient solution were (mu M) 500 Ca, 100 Mg, 300 K, 600 N (150 NH4, 450 NO3), 600 SO4, 2.5 P, 3 B, 2.5 Fe, 0.5 Zn, 0.5 Mn, 0.1 Cu at a pH of 4.7. The major solution nutrient concentrat ions were maintained at the nominal concentration with monitoring, fre quent additions and weekly renewal. Differentiation in yield between t he Al-tolerant and Al-sensitive line only occurred in the presence of Al indicating that, in the long term, none of the other metals tested could be used as an analog for Al. The visual symptoms in the roots of Cu toxicity (in both lines) and Al toxicity (in the sensitive line) w ere similar. The solution concentration (IJ-M) at which yield of the r oots of the tolerant line was reduced by 50% was, in order of increasi ng tolerance, Cu 0.5, Sc 1.1, La 7.1, Ga 8.6, Al 15, Zn 19, Fe 84, B 4 90 and Mn 600.