Shoot regeneration from leaf discs of Limonium perigrinum using thidiazuron

Shoots were regenerated from 12-mm diameter leaf discs derived from greenhouse plants of Limonium perigrinum (Bergius), with either zeatin or thidiazuron (TDZ), the latter producing five times the number of shoots. After 8 weeks exposure to a modified Murashige and Skoog basal medium (BM) supplemented with 3.0 mg/litre TDZ, an average of 13 shoots/disc formed, 90% of which were ≤ 1 mm long. There was no significant difference in the total number of shoots formed at 1.0-5.0 mg/litre TDZ, however at lower rates (1.0-2.0 mg/litre) a greater proportion of longer shoots (> 1 mm) developed. Shoots regenerated after 8 weeks from leaf discs exposed to BM with TDZ for from 2 h to 6 weeks before being transferred to growth-regulator-free medium. A mean of 4.8 shoots/disc formed from the shortest TDZ pulse period, with the majority being longer than 1 mm. Serial sections of discs pulsed with TDZ medium showed many suppressed shoot initials within the new tissue originating from the cut edge of the discs.