Abstract:In order to investigate the relationship between salt tolerances of jujube cultivar and polyamine and polyamine oxidase, the polyamine contents and polyamine oxidase activities in two-year-old plants of ‘Jingsixiaozao’ with strong salt tolerance and ‘Dongzao’ with weak salt tolerance were studied. The results showed that under 120 mmol L-1 NaCl salt stress, the polyamine contents in roots and leaves of two jujube cultivars enhanced, and increase degree of ‘Jingsixiaozao’ was significantly larger than that of ‘Dongzao’. As the extension of salt stress days, polyamine contents of roots and leaves decreased, and the decrease degree was in the order as: ‘Dongzao’ > ‘Jingsixiaozao’, leaves > roots, conjugated polyamines > free polyamines, spermine > spermidine, respectively. The activities of polyamine oxidases (PAO) were higher than that of diamine oxidases (DAO) in roots and leaves of the two jujube cultivars, the increase degree of weak salt tolerant cultivar ‘Dongzao’ was much greater than that of strong salt tolerant cultivar ‘Jingsixiaozao’ under salt stress. These indicate that salt tolerance of jujube cultivar has close correlation with composition and content of endogenous polyamines, and activity of polyamine oxidases. So, It is suggested that polyamine accumulation is beneficial to enhance salt tolerance of jujube cultivar.
