| heal.abstract |
X Malosorbus florentina Zucc. is a rare and endangered native species of Greece suitable for use as an ornamental plant in mountainous landscapes or in reforestations. In vitro cultures were started in early spring (March), from apical buds (before sprouting) of adult plants, on solid MS medium with 0.7 or 1 mg/L BA with or without 0.1 mg/L IBA. The percentage of buds producing shoots was very low. Nodal explants from these in vitro produced shoots were subcultured successfully with high shoot multiplication rates. Medium type, plant growth regulators and subculture period greatly influenced shoot regeneration. Five subcultures on MS medium with 1 mg/L BA and 0.1 mg/L IBA, lasting six weeks each, gave a high degree of shoots' proliferation. Culture of nodal explants on Woody Plant Medium with the same growth regulators increased the mean number of shoots as compared to MS medium, but induced morphological alterations to the shoots. Three weeks culture on a medium supplemented with 1 mg/L BA and 0.1 mg/L IBA followed by a further three weeks culture on a medium with half the concentration of BA led to increased shoot length. Nodal explants from the apical or basal part of long microshoots or entire short microshoots without the apex did not differ in their reaction in subcultures, while pieces of the initial explant, after the removal of shoots, could be subcultured for a second harvest of shoots. Nodal explants were also cultured on media with 0.2 or 2 mg/L TDZ and 0 or 0.1 mg/L IBA in all possible combinations giving numerous minute shoots; the lowest TDZ concentration giving the highest shoot number. Subculture of shoot clusters (2-3 shoots) from TDZ media on MS medium without plant growth regulators or with 0.5 mg/L BA and 0.05 mg/L IBA or 1 mg/L BA and 0.1 mg/L IBA induced multiplication of the shoots, but only shoot-clusters coming from the low TDZ concentration produced elongated shoots suitable for subculture. |
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