Variability in essential oil chemistry and plant morphology within a leptospermum scoparium population

Abstract

Essential oil composition and plant morphology were observed over four years in individual plants raised from seed of a wild population of Leptospermum scoparium (Myrtaceae) collected at a single site in New Zealand. Principal component analyses of data from young and mature plants showed no significant grouping of plants on the basis of oil composition, but identified differences between the essential oil components contributing most to variation in oil composition in both young and mature plants. The dominant variables were six sesquiterpene components in young plants, and three monoterpenes and two sesquiterpenes in mature plants. Levels of these components differed significantly at the population level between young and mature plants and also within and between seasons. Levels of all these components varied markedly within and between individual plants at all sample times. The habit, leaf size and density, and stem and foliage colour also varied markedly between individual plants. The variation observed indicates the need for more extensive sampling and statistical analysis over more than one growing season if sufficiently reliable data on essential oil compositions in individual plants or populations are to be obtained for chemotaxonomic or plant selection purposes. © 1998 Taylor & Francis Group, LLC.