An Effcient Method for the Micropropagation of Lavenders: Regeneration of a Unique Mutant

Abstract

A novel protocol for the micropropagation of lavender plants (Lavandula angustifolia, cv. “Lavender Lady”) has been developed. Young leaves were sterilized, lacerated with a sharp razor blade and incubated in the dark on regeneration medium (MS basal salts) containing 9 μM thidiazuron (TDZ) or 2,4-Dichlorophenoxyacetic Acid (2,4-D). Callus tissue appeared along injured areas of all tissue after two weeks. Multiple shoots formed from callus obtained from the TDZ treated leaves after an additional two to four weeks. However, calli forming on the 2,4-D treated tissue did not produce any shoots. Regenerated shoots were transferred to a growth medium (MS basal salts containing 0.05 μM napthaleneacetic acid (NAA)) to allow growth and development to approximately 1cm in length. Subsequently, shoots were dipped into a 0.80% IBA powder before transferring to fresh growth medium. This treatment resulted in 100% rooting of lavender shoots after one to four weeks. Rooted shoots were planted in potting soil, acclimatized, and then transferred to a greenhouse. This procedure was used to regenerate over 400 lavender plants. In these experiments, the emerging calli were treated with ethyl methane-sulfonate (EMS) to induce mutation in regenerating plants. One of the regenerated plants (the EO mutant) produced an essential oil that was drastically different in composition (the relative abundance of several mono- and sesquiterpenes) from that of wild type plants. This mutant provides a useful tool for investigating regulation of mono- and sesquiterpene production in plants.