Abstract
The amounts of free polyamines in Hiproly barley callus increased when the callus was deprived of 2, 4-D. At the 60th day after auxin withdrawal, the putrescine level was especially elevated in the callus. At the 90th day after auxin withdrawal, the levels of putrescine and spermine were elevated. The spermine level drastically increased with root formation, and the putrescine level in bound polyamines increased in the callus after auxin withdrawal. These results showed that the amounts of polyamines in Hiproly callus increased with root formation on the callus. In relation to changes in the levels of polyamines of Hiproly callus, arginine decarboxylase activity remained almost constant, but ornithine decarboxylase activity increased in the callus after 2, 4-D withdrawal. Ornithine decarboxylase activity was about 1.7-fold higher than arginine decarboxylase activity when Hiproly callus was deprived of 2, 4-D. It is suggested that the enhancement of ornithine decarboxylase activity is involved in the mechanism leading to elevated polyamine levels in the callus.
