Abstract: It is possible to induce in vitro regeneration of fruit-like structures from tissue pieces excised from young pistil and young fruit of Lycopersicon esculenturn Mill. These fruit-like structures could be cultured in vitro to maturation, meanwhile they became red coloured. Under dissection it was observed that the fruit-like structure consists of fruit flesh and fruit coats without seeds and plancentae. Tests of exogenous hormones and explant ages revealed: 1. Supplement with exogenous cytokinins alone could induce the explants excised from the pistils to regenerate the fruit-like structures, and the highest induced frequency (50%) was obtained when 0. 5 mg/L zeatin was supplemented. Exogenous auxin seems unnecessary. 2. When tissues of young fruit were used as explants, all explants excised from 4—12 mm (diameter) young fruits could be induced to differentiate the fruit-like structures on medium supplemented with exogenous hormones. However, the hightest frequency of induction (62.5%) was obtained only in tissues of explants excised from 8 mm (diameter) sized fruit and cultured on medium supplemented with 2 mg/L of 6-BAP and 1 mg/L of NAA where regermination of the fruit-like structures took place. In order to investigate the expression of cell totipotency arisen in the regeneration of the fruit-like structure a concept of partial expression of plant cell totipotency was proposed and discussed.

Key words: Lycopersicon esculentum, In vitro culture, Regeneration of fruit-like structure