Qualitative Study on the Production of the Allelochemicals Benzoxazinones by Inducing Polyploidy in Gramineae with Colchicine.

The possibility of inducing polyploidy in grasses by treatment with colchicine and its effect on the production and root exudate content of 2,4-dihydroxy-7-methoxy-2 H-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-2 H-benzoxazin-3-one (DIBOA) was studied in wheat, corn, and rye. Caryopses treated with colchicine at concentrations in the range of 0.1-10 mg/mL for 8 and 48 h and with inoculation of the growth medium are markedly affected in terms of both the distribution and concentration levels of allelochemicals in plants. A greater accumulation was observed in the root with respect to the stem, and this increased with an increasing concentration of colchicine and with treatment time. Analysis of the compounds released by root exudates showed that treatment with colchicine at a concentration higher than 1 mg/mL caused a significant increase in the concentrations of allelochemicals measured in the growth medium. It is proposed that treatment with colchicine of seedling caryopses mixoploids plant populations and that the overall effect is an increase in the levels of allelochemicals released. The ecological implications of this behavior are discussed along with the impact of plant-plant interactions (allelopathy).