Direct shoot regeneration from leaf and internode explants of Aloysia polystachya [GRIS.] mold. (Verbenaceae)

Summary Adventitious bud regeneration from leaf and internode explants of Aloysia polystachya was achieved. Shoots from nodal segments grown in vitro were cut into pieces and used as sources of explants. Organogenesis was induced from both explants cultured on quarter-strength Murashige and Skoog (MS) semisolid medium (plus sucrose 5 g l⁻¹) containing different combinations of 6-benzyladenine (BA) and α-naphthaleneacetic acid (NAA) under 116 μmol m⁻² s⁻¹ photosynthetic photon flux density (PPFD), 14-h photoperiod, and at a temperature of 27±2°C. The type of explant markedly influenced organogenesis and growth of the regenerated shoots. The regeneration frequencies were higher with leaf explants, while the number of shoots formed per responsive explant was greater with internode explants. However, the growth of regenerated shoots from internodes was seriously affected by vitrification. The number of shoots produced per responsive leaf explant increased from one to seven as the percentage of leaf explants producing shoots increased from 20 to more than 80%. NAA at 0.05 μM in combination with BA at 0.5μM induced the highest regeneration rate (87±8.8%) after 20 d of culture, yielding 5.9±0.8 shoots per responsive leaf explant. Histological examination confirmed the occurrence of direct organogenesis. The regenerated shoots from the best induction treatment were transferred to a fresh medium without plant growth regulators for 30 d. Finally, the elongated shoots were rooted by pre-treatment in an aqueous solution of NAA at 500 μM for 2 h and transferred to 1/4 MS. All plantlets raised in vitro were phenotypically normal and successfully hardened to ex vitro conditions. An experimental field plot with 2-yr-old in vitro-regenerated plants was established.     

Distribution and essential oils of Salvia pomifera subsp. pomifera (Labiatae) on the island of Crete (S Greece)

The distribution of Salvia pomifera subsp. pomifera (Cretan sage) on the island of Crete is presented. The essential oils of six populations scattered on the island are studied. The essential oil content varies from 2.1–4.2%, whereas the main oil components were in all cases α- and/or β-thujone (27.4–72.3% and 7.1–40.8%, respectively). The comparison of our results to literature data, suggest that S. pomifera can be distinguished from S. fruticosa (Greek sage), on the basis of its essential oil composition.     

Microbial transformations of (−)-α- and (+)-β-thujone by fungi of Absidia species

The microbial transformations of (−)-α- and (+)-β-thujone (1a and 1b) in cultures of Absidia species: Absidia coerulea AM93, Absidia glauca AM254 and Absidia cylindrospora AM336 were studied. The biotransformations of (−)-α-thujone (1a), by these fungi strains, afforded mixtures of 4-hydroxy- and 7-hydroxy-α-thujone (2 and 3). Aforementioned fungi strains were also able to hydroxylate of (+)-β-thujone at C-7 position. Only A. glauca AM254 transformed 1b to 8-hydroxy-β-thujone (7) and (2S)-2-hydroxyneoisothujol (6). The (4R)-4-hydroxyisothujole (5) was identified as one of the major metabolite of (+)-β-thujone (1b) in culture of A. cylindrospora AM336. This strain was also able to introduce hydroxy group to C-4 position in 1b without reduction of carbonyl group at C-3. The absolute configuration of all chiral centers of new (4R)-4-hydroxyisothujol (5) and (2S)-2-hydroxyneoisothujol (6) were established taking into account the configuration of (+)-β-thujone (1b) and their spectral data.     

Variation of Salvia fruticosa Essential Oils on the Island of Crete (Greece)

The essential oil content and composition of Salvia fruticosa (Greek sage) plants growing wild in 20 localities scattered on the island of Crete are studied. The results of our analyses have shown a noticeable variation in the essential oil content (ranging from 1.1 up to 5.1 %) and the amount of the four main oil components: 1,8-cineole (22.7 ? 64.2% of total oil), α-thujone (1.0 ? 19.2%) β-thujone (0.9 ? 25.6%) and camphor (0.8 ? 30.3%). Discriminant analysis revealed that the variation pattern of the essential oil content and the amount of the four main oil components is geographically related, following a W → E direction. Plants grown in Western Crete show a lower essential oil content and their oils are characterised by the predominance of 1,8-cineole. On the other hand, those collected from Eastern Crete exhibit higher values in essential oil content and their oils, besides 1,8-cineole, are rich in α- and β-thujone or camphor. Our findings are further discussed in relation to literature data.