Abstract:

A large number of Populus simonii vigorous protoplasts were isolated from embryonic cell suspension culture. The yield of these protoplasts amounted to 3.8 × 10⁷g^-1FW. The protoplasts were cultured in a Km8p liquid medium containing 2, 4-D 3.0mg/L, NAA 0.2mg/L, and KT 0.2mg/L, and in higher density (3 × 10⁶/mL) and thinner layer, which have been proved to be favourable to the division and growth of the protoplasts. When glucose was used in the medium as the only carbon source, it was of benefit to the sustained division of protoplasts. The protoplast plating effeciency increased when the medium contained organic nitrogen. It could be favourable for further division to decrease osmotic pressure and separate mass into several dishes when cell colonies formed from protoplast. There is a evident difference in differentiation frequency of the calli on various differentiation media. The isoenzyme analysis results showed that the phosphopentose pathway and TCA cycle were more active in the calli with high ability of shoot formation, and the activities of GOT, EST, and PEROX were higher. The shoots of 2 - 3cm in height were cut off from the calli and rooted on 1/2 MS medium.After transplantation into pots, the regenerated plants grew vigorously in greenhouse.

Key words: Populus simonii, Protoplast culture, Plant regeneration, Isoenzyme