Modification du métabolisme du phosphore dans les feuilles et les racines de froment (Triticum aestivum) sous l’action des herbicides triaziniques

Abstract

Summary Atrazine and promethrine were applied at 1 ppm during 20 h and at 0.02 ppm during 48 h to the roots of twelve day old wheat seedlings in nutrient solution. RNA, DNA and acid-soluble mineral phosphorus were determined in the roots and in the leaves 1, 2, 3, 5 and 7 days after the treatment. In the leaves of seedlings treated with lethale dose, acid-soluble mineral phosphorus increased progressively and reached 124–127% of the control at the seventh day. RNA decreased by 9–16% to 23–24% while DNA remains practically unchanged. In the roots, acid-soluble phosphorus decreased by ± 10%, RNA by 23–25 to 31–34% and DNA by 18–24 to 35–46%. The application of sublethale dose does not involve increasing of nucleic acid biosynthesis neither in the leaves nor in the roots.