Fast-propagating and maintenance system for an Fe-efficient apple genotype in vitro. I. Stem apex culture in vitro and its maintenance

摘要

An Fe-efficient apple genotype, Malus xiaojinensis, was employed as experimental material to find techniques of both rooting and maintenance via propagation of test-tube seedlings in vitro. Seedling height, longitude of shoot in diameter, and rooting rate of M. xiaojinensis were significantly increased by pre-culture of the test-tube seedlings in medium of MS+0.25mg/L BA+0.05mg/L NAA. It was obviously accelerated for root formation by either lowering N concentration to 15 mM in the medium or dark culture in 3 days in the same medium but IBA of 1.0 mg/L. Compared to one-step method, the two-step rooting method had a significantly higher rooting percentage, in which the micro-propagated shoots were inserted into root induction medium with auxin before transferred them into 1/2 MS medium without auxin.