Protoplasts isolated from cotyledon-derived callus of Actinidia chinensis Planch. var. chinensis (2N ¼ 2x ¼ 58) were fused with mesophyll protoplasts of Actiniadia kolomikta (Maxim. et Rupr.) Maxim (2N ¼ 2x ¼ 58) using a PEG method. Plantlets were regenerated from the fusion product clone 11. RAPD analyses, chromosome numbers of root tip cells and fluorescence peak position of leaf nuclei confirmed that clone 11 was an interspecific somatic hybrid (2N ¼ 4x ¼ 116) between A. chinensis and A. kolomikta. The chilling tolerance of the somatic hybrid was tested with in vitro leaves at low temperatures. Based on data of leaf thickness, electroconductivity, proline levels, malondialdehyde content and activity of superoxide dismutase, dendrogram cluster analysis suggested that the interspecific somatic hybrid was similar to A. kolomikta, and might have a higher capacity of cold resistance than A. chinensis.

Calluses from seasonal mature shoots of Taxus globosa Schltdl. were subcultured in new medium containing 1 mg l-1 NAA, 0.5 mg l-1 2, 4-D, 0.025 mg l-1 BA. Calluses growing for 30 and 40 days in a medium added with 0.1-5.0 mg l-1 of chlorocholine chloride (CCC) were harvested for determination of taxol, phenolic compounds, and for polyphenol oxidase (PPO) activity. The results showed that by increasing the CCC concentration, callus growth was decreased, phenolic level was raised up, but taxol content and PPO activity changed differently. The highest taxol production (0.0269 mg g-1 dry weight callus) and PPO activity (4.53 U g-1 fresh weight callus) were achieved at day 40 with a medium containing 0.5 mg l-1 CCC. Possible reason of higher taxol level stimulated by CCC is discussed in the text.