<Emphasis Type="Italic">In vitro</Emphasis> regeneration of <Emphasis Type="Italic">Echinacea pallida</Emphasis> from leaf explants

Summary A method has been developed for the induction of adventitious shoots from leaf tissue of Echinacea pallida with subsequent whole-plant regeneration. Proliferating callus and shoot cultures were derived from leaf tissue explants placed on Murashige and Skoog medium supplemented with 6-benzylaminopurine and naphthaleneacetic acid combinations. The optimum shoot regeneration frequency (63%) and number of shoots per explant (2.3 shoots per explant) was achieved using media supplemented with 26.6 μM 6-benzylaminopurine and 0.11 μM naphthaleneacetic acid. Rooting of regenerated shoot explants was successful on Murashige and Skoog medium, both with and without the addition of indole-3-butyric acid. All plantlets survived acclimatization, producing phenotypically normal plants in the greenhouse. This study demonstrates that leaf tissue of E. pallida is competent for adventitious shoot regeneration and establishes a useful method for the micropropagation of this important medicinal plant.     

Micropropagation ofMinthostachys mollis (H.B.K.) grieseb. and essential oil composition of clonally propagated plants

Summary Cultures ofMinthostachys mollis were established from nodal explants obtained under aseptic conditions. Explants were cultured on Murashige and Skoog (MS) half-strength medium containing 6-benzyladenine (BA), and/or naphthaleneacetic acid (NAA). Optimum numbers of healthy shoots were induced on media containing 0.05 μM NAA plus 2.2 μM BA; higher concentrations caused more hyperhydricity and less extension. Rooting was achieved on half-strength MS medium with 0.05 μM NAA. Plantlets were acclimatized and successfully transferred to soil. Essential oil composition of the regenerated plants were determined by gas chromatography/mass spectrometry and little differences were found in the essential oil composition with the plant grown in the wild.     

Application of near-infrared spectroscopy in quality control and determination of adulteration of African essential oils

An evaluation has been made of the potential of near-infrared (NIR) technologies in the assessment of essential oil components and in the identification of individual essential oils. The results showed that cross-validation models are able to predict accurately almost all of the components of essential oils. In different cinnamon (Cinnamomum zeylanicum) and clove (Syzygium aromaticum) essential oils, which showed a similar composition, 23 components (representing 97.8-99.9% of the oil) were accurately predicted, as well as 20 components (93.0-99.1%) in Cinnamomum camphora (ravintsara), 32 components (92.3-98.1%) in Ravensara aromatica (ravensara), and 26 components (96.6-98.4%) in Lippia multiflora. For almost all of the components, the modelled and reference values obtained by GC-FID were highly correlated (r2 > or = 0.985) and exhibited a low variance (less than 5%). The model was also able to discriminate between the ravintsara and ravensara essential oils. It was shown that two commercial oils labelled as R. aromatica were actually ravintsara (C. camphora), revealing the misidentification of these essential oils in the marketplace. The study demonstrates the application of NIR technology as a quality control tool for the rapid identification of individual essential oils, for product authentication, and for the detection of adulteration.     

In vitro regeneration of Echinacea purpurea from leaf explants

Efficient plant regeneration was achieved via organogenesis from callus cultures derived from leaf tissue of Echinacea purpurea. Proliferating shoot cultures were obtained by placing leaf explants on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) combinations. MS medium supplemented with BAP (4.44 M) and NAA (0.054 M) was the most effective, providing high shoot regeneration frequencies (100%) associated with a high number of shoots per explant (7.7 shoots/explant). Plantlets were rooted on MS medium alone or in combination with different concentrations of indole-3-butyric acid (IBA), and high rooting and survival was achieved using MS media without plant growth regulators (PGR). All plantlets survived acclimatization producing healthy plants in the greenhouse. This study demonstrated that adventitious shoot regeneration of E. purpurea from leaf explants can be a useful method for the multiplication of this important medicinal plant.     

Micropropagation and acclimatization of Hedeoma multiflorum

A method for the micropropagation of Hedeoma multiflorum Benth from shoot tips or nodal segments was developed. Proliferating microshoot cultures were obtained by placing shoot tips or nodal segments on half-strength Murashige and Skoog (1962) medium supplemented with 22.2 μM BA or 22.2 μM BA plus 0.05 μM NAA. Individual shoots were excised and transferred into rooting medium containing auxins (IBA, NAA or IAA). Rooting of shoots was better on half-strength MS medium containing 0.6 μM IAA than on half-strength MS medium without growth regulators. Rooted plantlets were successfully acclimatized to soil. Preconditioning at different sucrose concentrations prior to acclimatization had no effect on plant establishment, but influenced plant quality. This revised version was published online in June 2006 with corrections to the Cover Date.     

Micropropagation of Lippia junelliana (Mold.) Tronc.

A method for the micropropagation of Lippia junelliana (Mold.) Tronc. from shoot tips or nodal segments was developed. Proliferating microshoot cultures were obtained by placing shoot tips or nodal segments on full strength Murashige and Skoog medium (MS) supplemented with 4.4 μM benzyladenine (BA) or 0.04 μM indolebutyric acid- (IBA) plus 4.4 μM BA. The rooting of shoots was better on full-strength MS medium without growth regulators. Rooted plantlets were successfully acclimatized to soil. The shoot cultures showed a lower essential oil accumulation in comparison with parent plants. Essential oil accumulation is closely related with growth and shows a negative correlation with shoot proliferation. This revised version was published online in June 2006 with corrections to the Cover Date.