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Die Bodenkultur - Journal for Land Management, Food and Environment
S. M. ULLAH and M. H. GERZABEK:
Influence of Fulvic and Humic Acids on Cu- and V-Toxicity to Zea meys (L.)
Zea mays (L.) was grown in a nutrient solution to investigate and evaluate the influence of humic (90 and 180 OD/pot) and fulvic acids (27 and 54 OD/pot) on phyto-toxicity due to excess Cu (1.0 and 2.0 mg/L) and V (0.5 and 1.0 mg/L). In most cases fulvic and humic acids improved corn tissue production markedly in heavy metal free nutrient solution probably by facilitating the uptake of cations as chelates and affecting metabolic processes. All heavy metal treatments caused a pronounced depression in yields. Both root and shoot growth of maize plants were more severely effected by Cu than V treatments. Fulvic and humic acids moderately increased the corn growth in copper enriched nutrient solution, but none of them could prevent typical Cu-excess chlorosis. Humic and fulvic acids enhanced the growth of corn plants in V-treated nutrient solution. They not only eliminated the toxic effects due to excess V but also stimulated the growth of roots and shoots in V-enriched nutrient solution. This is probably due to the uptake of V-FA or V-HA complexes, which obviously have no toxic effects in corn toxic effects in corn tissue and the ameliorating influence of the available vanadium at low concentrations to plant growth. Humic acids were found to be more capable of stimulating corn growth than fulvic acids in V-enriched nutrient solution.