Growth, inorganic content and essential oil quality of Buchu (Agathosma betulina) found in its natural habitat in the Cederberg Mountains
The study was conducted at eleven sites in the Cederberg Mountains, about 200 km north of Cape Town, during March 2006, to gain some information on soil characteristics of natural habitats of Buchu (Agathosma betulina) and determine possible variations in Buchu oil quality at different sites. Plant samples were collected and plant height was recorded at each site. Soil samples were taken as close as possible to the sampled plants, while the direction of the slope was also recorded. The soil analyses indicated that soils of the Cederberg Mountains are mostly very sandy with low levels of nutrients. The pH of the soil was found to vary between pHKCl 3.7and 5.3. Plant height varied with age and between sites and the analyses of the leaves indicated low levels of most of the inorganic elements. Essential oil from the sites showed slight variations, but generally low pulegone levels, high levels of diosphenol and the absence of measurable amounts of cis-trans acetylthio-p-menthan-3-one isomers indicated that all the material originated from pure A. betulina genetic material. High levels of diosphenol also indicated that the material was from diosphenol chemotype.