Micropropagation of Atriplex halimus L.

Atriplex halimus L. is a xero-halophyte evergreen perennial shrub, widely found in coastal Mediterranean areas. In vitro cultures were successfully established from shoot tip explants excised in spring from greenhouse grown plants. Explants were cultured either on hormone-free MS medium or on MS medium supplemented with 1.0 mg L-1 BA, ZEA, 2iP, KIN or TDZ. The highest shooting percentage (96%) occurred in explants cultured on the hormone-free medium. Moreover, a high percentage of explants rooted simultaneously with shoot production on the hormone-free medium (85%) and on the KIN medium (50%). Differences in the number of produced shoots (1.2-1.6) were not found, whereas shoots in the hormone-free medium had the greatest length (3.9 cm). Explants initially cultured on a medium containing BA, ZEA or KIN were subcultured onto the same medium, while explants initially cultured on the hormone-free medium were subcultured onto the same hormone-free medium, as well as on all the above cytokinin-containing media. Explants initially cultured on a medium with 2iP or TDZ were not subcultured because of their poor response during establishment. Explants initially cultured on either the hormone-free medium or BA or KIN-containing medium and subcultured on a BA or KIN medium showed the highest multiplication rate. Similarly, in a second subculture on a BA or KIN containing medium explants responded at high percentages (79-93%) producing on average 4-7 shoots per explant with 1 cm of mean length.