Effect of medium on in vitro growth and ex vitro establishment of Globularia alypum L.

Globularia alypum L. is an evergreen small shrub, native in dry rocky areas of Mediterranean countries, that from November to May bears lilac-blue flowers in globose heads. The in vitro propagation of the species will facilitate its use as ornamental. Well-developed seeds without the hull, disinfested in 10% commercial bleach, achieved 83% germination and germinated faster on full strength (T 50 =7) than half strength (T 50 =9) solid (8 g l -1 agar) MS medium with 20 g l -1 sucrose. Seeds with the hull disinfested in 15% commercial bleach for 20 min had reduced germination (50%) which delayed by five days. After 2 months culture on full MS, 79% of the seedlings were hyperhydrated and failed to acclimatize ex vitro, while non- hyperhydrated 2-month-old seedlings were acclimatized with 100% success on peat - perlite (1:1, v/v); increasing the perlite ratio in the medium decreased the ability of acclimatization. Node explants, excised from 2-month-old seedlings grown in vitro, were cultured on various NAA and BA concentrations to test their ability for shoot regeneration. One hundred percent of the explants gave two shoots per explant when cultured on solid (8 g l -1 agar) MS, with 20 g l -1 sucrose, without plant growth regulators, and half of them rooted on the same medium after two months in culture. However, 67% of the shoots developed were hyperhydrated and so their ability for ex vitro establishment was reduced. Increasing agar ratio up to 20 g l -1 eliminated hyperhydration but decreased to half the number of shoots regenerated and the shoot length. Double sucrose concentration did not affect hyperhydration.