An Improved System for Shoot Regeneration from Stem Explants of Lombardy Poplar (Populus nigra L. var. italica Koehne)

Abstract

We developed a system for the regeneration of Lombardy poplar (Populus nigra L. var. italica) shoots from internodal stem explants. Using this system, shoots regenerated from 87% of the stem explants placed on Murashige and Skoog (MS) medium supplemented with 0.1 mg/L indole-3-acetic acid and 0.5 mg/L benzylaminopurine without undergoing callus formation. About 80% of the in vitro regenerated shoots developed roots on MS medium supplemented with 0.5 mg/L indole-3-butyric acid and 0.02 mg/L 1-naphthylacetic acid. Well-rooted seven-to eight-week-old regenerated plants could be transferred to soil for further growth and the survival rate of such plants after three weeks was 88%. The protocol presented here is simple and economical because it does not rely on pre-incubation in callus induction medium or repeated subculture in shoot induction medium containing trans-zeatin, an expensive substance. The in vitro regeneration system presented here could be used for evaluation of radiation sensitivity for Lombardy poplar tissues.