Absorption, Translocation, and Metabolism of Prometryne in Cotton and Soybean

Abstract

Absorption, translocation, and metabolism of 14C-labeled 2,4-bis (isopropylamino)-6-methylmercapto-s-triazine (prometryne) from solution cultures by cotton (Gossypium hirsutum L., var. DPL smoothleaf) and soybean (Glycine max Merr., var. Lee) were investigated. Cotton (moderately tolerant) and soybean (sensitive) absorbed essentially equal amounts of prometryne. Whereas 14C was uniformly distributed in soybean, it was concentrated in the lysigenous glands and in the root primordia of cotton. Soybean had a considerably higher concentration of radioactivity in shoots than in roots, whereas the reverse was true in cotton. The major methanol extractable 14C-labeled component in the roots and shoots of both species was prometryne. Both species converted some prometryne to the derivative, 2,4-bis(isopropylamino)-6-hydroxy-s-triazine (hereinafter referred to as hydroxypropazine), but cotton shoots had a slightly higher percentage of the latter than the soybean shoots. The concentration of prometryne in soybean shoots was about four times greater than in cotton shoots. Differential translocation of prometryne appeared to be a major factor contributing to the difference in susceptibility between cotton and soybean.