EFFECT OF HORMONE-TREATMENT ON CALLUS FORMATION AND ENDOGENOUS INDOLE-ACETIC ACID AND POLYAMINE CONTENTS OF SOYBEAN HYPOCOTYL CULTIVATED IN-VITRO

Callus was formed and grew well when explants were cultured on medium containing both NAA and kinetin. The endogenous IAA in hypocotyls was accumulated on the medium with both hormones, showing the suppression effect of kinetin on IAA degradation. Besides, the accumulation of NAA in hypocotyl explants was also markedly enhanced by kinetin in the cu lture medium containing both hormones. In the MS+NAA+Kinetin treatment , the accumulation of spermidine and spermine occurred on the sixth da y and was accompanied by rapid callus growth. Increasing putrescine le vels were found during the first 3 days in culture when cell multiplic ation was rapid. The accumulation of endogenous IAA, exogenous NAA, sp ermidine, and spermine are in proportion to the callus growth in soybe an hypocotyl explants.