INTERACTION BETWEEN ISOMERISM AND PLANT PHARMACOLOGICAL ACTION .5. STRUCTURAL CHARACTERISTICS OF S-TRIAZINE COMPOUNDS INDUCING RHIZOME IN CYPERUS-SEROTINUS ROTTB

Rhizome induction activities of the s-triazines and synthetic cytokini ns were measured on Cyperus serotinus ROTTB. tuber in the dark. The (R )-enantiomers of 2-alpha-methylbenzylamino-6-chloro-s-triazine compoun ds having a small alkyl group at 4-amino moiety stimulated the rhizome induction. Medium sized or long-chain alkylamino groups (butyls to de cyl) resulted in decrease in activity. Their (S)-antipodes did not cau se the rhizome induction. The racemates substituted with an ethyl or p ropyl group at the benzylic position of the 2-benzyl-amino-4-methyl (o r ethyl) amino-6-chloro-s-triazines also exhibited a significant rhizo me inducing activity. The activity of the methoxy or methylthio deriva tives of corresponding chloro-s-triazines that was active on rhizome i nduction was maintained. An s-triazine ring system was essential for t he rhizome induction. Kinetin and synthetic cytokinin compounds, forch lorfenuron [1-(2-chloro-4-pyridyl)-3-phenylurea- and thidiazuron [1-ph enyl-3-(1,2,3-thidiazol-5-yl)urea], significantly stimulated rhizome i nduction similar to 6-benzylamino-purine (BA).