Abstract:

The effects of NAA, IBA, ZT and 6-BA on the growth and the changes on endogenous levels of PAs and nitric oxide were investigated by using regeneration system of Malus hupehensis Rehd. in vitro. As a result, the increase rate of fresh weight and the contents of protein, polyamines (PAs) and nitric oxide (NO) increased significantly in MS medium supplemented with 0.02-1.00 mg·L^-1 NAA or IBA, and the increases were the highest at concentrations of 0.10 - 0.50 mg·L^-1. One more thing，the effects of NAA on the increase rate of fresh weight and putrescine content were higher than that of IBA at the same concentration. With the increase concentration of ZT or 6-BA at 0.08 - 4.0 mg·L^-1, the increase rate of fresh weight, protein, PAs and NO contents increased gradually. Moreover, the effects of 6-BA on increase rate of fresh weight and putrescine content is higher than that of ZT at the same concentration. Auxin and cytokinin promoted the growth accompanied with the elevated production of PAs and NO, and the growth dynamics showed the similar trend with the contents of PAs and NO in explants in vitro.

Key words: Malus hupehensis Rehd., nitric oxide, polyamine, auxin, cytokinin