Glands, essential oils and in vitro establishment of Helichrysum italicum (Roth) G. Don ssp. microphyllum (Willd.) Nyman

In this work, two Helichrysum italicum (Roth) G. Don ssp. microphyllum (Willd.) Nym. genotypes (genotype 1 and genotype 12) collected from different areas of Corsica were used. After the taxonomic identification based on several specific morphological characters, the two genotypes were subjected to microscopic studies. The precise structure of the glandular trichomes, secreting essential oils, on the flower heads and leaves of H. italicum (Roth) G. Don ssp. microphyllum (Willd.) Nym. are described here for the first time. Volatile constituents from both field-grown genotypes1 and 12 were analyzed and their composition compared: monoterpenes were the most abundant class of compounds with nerol and its esters as the main metabolites. Genotype12 was used to establish an efficient micropropagation protocol. For proliferation, different concentrations of 6-benzylaminopurine (BAP) alone or in combination with indole-3-butyric acid (IBA) were tested adding sucrose (20% or 30%). To define the optimal conditions for in vitro rooting, the shoots obtained were divided and transferred to the culture medium without growth regulators or enriched by different auxins in combination with sucrose (20% or 30%). Acclimatization, carried out in different conditions was easy, registering high survival percentages. The results achieved in this study allowed to obtain selected and standardized plants suitable for the exploitation in industrial sectors of this interesting species.