Physiological effects & degradation of S,S,S-tributylphosphorotri-thioate by cotton leaves as shown by the P32 & S35 labeled compounds

The first organic thiophosphorus compound reported to induce and accelerate abscission was S,S,Stributylphosphorotrithioate (6, 14). Goyette (5) tested homologous trialkyl phosphorotrithioites and the corresponding trialkyl phosphates for abscissioninducing activity in the greenhouse and noted that only the former were active. Hall et al. (paper presented at the 134th National Meeting Am. Chem. Soc. Chicago, 1958, by W. C. Hall, F. R. H. Katterman, C. S. Miller, & F. A. Herrero) studied a wide array of phosphorus and sulfur containing compounds for abscission properties and confirmed Goyette's findings. Both groups of workers (5, & Hall et al.) concluded that the sulfur moiety was responsible for the defoliation response. Our study is primarily concerned with the effect of this defoliant on respiration and on the -SH groups of water soluble proteins in the leaf, since both have been shown to be influenced by other defoliants (7, 10). Tn addition, we studied the rate and manner of degradation of this defoliant in the cotton leaf before and during abscission.