Résumé
In vitro seedlings were used as explants for protocorm like bodies (PLBs) production which in turn were used for regeneration purpose. PLBs were induced from the base of seedlings (1.0-1.5 cm in size) in MS + BAP (8.88 µM). After 90 days of inoculation, PLBs production rate started declining and most of the PLBs turned into plantlets. Preculture of seedlings in 1.0 µM thidiazuron (TDZ) for 7 days and transfer to BAP supplemented medium resulted in production of 16 PLBs per seedling within 90 days of culture. Increase of TDZ concentration to 2.5 µM and preculture time 15 days, resulted in induction of highest number of PLBs (19 PLBs per seedling) in the basal medium. The results emphasized the importance of thidiazuron (TDZ) concentration and preculture time for PLBs proliferation from the base of seedlings. The PLBs thus produced were used for regeneration studies. Irrespective of single, segmented or clumps of PLBs, the regeneration response was 100% in 2,4-D (4.52 µM) and KN (4.64 µM) but when KN was replaced by BAP (8.88 µM), response was observed only in clumps of PLBs, whereas in single and segmented ones it was 99 and 97%, respectively. Regenerants developed stout root system in half strength M medium supplemented with 2.84 µM of IAA and transferred to greenhouse with 90% survival. The present study holds tremendous potential as the mother plant is not destroyed and PLBs are produced as a continuous system.