UPTAKE AND FATE OF TRITICONAZOLE APPLIED AS SEED TREATMENT TO SPRING WHEAT (TRITICUM-AESTIVUM L.)

Following seed treatment of wheat (Triticum aestivum L.) with C-14-lab elled triticonazole at a dose of 1.8 g kg(-1) seed, the uptake of radi oactivity by shoots and roots was investigated from the two- to three- leaf stage up to the beginning of the booting phase, 80 days after sow ing. Triticonazole equivalents taken up by wheat plants reached 5.7% a nd 14.6% of the applied dose in the shoots and the roots, respectively . Between the two- to three-leaf stage and the beginning of the bootin g phase, the concentration of triticonazole equivalents in the shoots decreased from 2.5 to 0.15 mu g g(-1) fresh weight. This was attribute d to uptake of triticonazole by roots not keeping pace with shoot grow th and increased retention in the roots of triticonazole taken up. The main factor limiting the uptake of triticonazole by the roots may be the rapid growth of the uptake-active apical root parts out of the dre ssing zone which had formed in the soil. Distribution of triticonazole equivalents taken up by the main shoot showed a decreasing concentrat ion gradient from the oldest to the youngest leaf. An increase in the seed treatment dose was investigated as a way to increase the concentr ation of triticonazole in the shoots, but its influence remained limit ed. (C) 1998 SCI.