1-NAPHTHYLACETIC ACID SLOW-RELEASE POLYMERIC FORMULATIONS - AUXIN TYPE EFFECT IN TOBACCO LEAF SEGMENTS IS AFFECTED BY STRUCTURE AND HYDROLYSIS

New slow release formulations (SRF) of 1-naphthylacetic acid (NAA) wer e synthesised and the expression of their auxin-like activity was exam ined by studying their effect in inducing callus formation and organog enesis in leaf segments of tobacco. The SRF were water-soluble copolym ers of acrylamide containing side-linkages with NAA, the latter being released during hydrolysis (cleavage of chemical bond). Callus formati on was assessed by fresh weight measurements and that of organogenesis , morphologically A shift of the effective (optimal) concentrations to higher values was noticed when increasing the polymer molecular weigh t or the content of NAA in the polymeric formulations. The relationshi p between polymer structure, hydrolysis rate and the biological effect was obvious.