Analysis of the Change of Polyamine during the Cold Treatment in Spring Radish Young Cotyledons and Hypocotyls

The concentration of polyamine and the relationship between the concentration of PA and cold resistance were analysed during the cold stress in the cotyledons and hypocotyls of young spring radishes. The concentration of PUT was increased during the cold stress in the cotyledons and the concentration of PUT and SPD was changed significantly all the stress time. From the results, we suggested that PUT and SPD were synthesized against cold stress or separated from the bound PA during the cold stress. But, the concentration of SPM was not significantly changed during the cold stress. Only SPD existed in the control hypocotyls. The concentration of SPD was increased during the cold stress, but was decreased dramatically during continusly cold stress. The reactivity against stress of hypocotyls was generally more sensitive during the cold treatment than that of the cotyledons because of the lower concentration of PA in the hypocotyls. PUT and SPD were responsible for the resistance of cold stress in the cotyledons and PA did not play an important role on the resistance of cold stress in the hypocotyls. In this study we suggest that PUT and SPD were responsible for the increase of the resistance against the cold stress.