Morphology and Anatomy of Leaves of Eucalyptus camaldulensis Clones: Variation Between Geographically Separated Locations

Abstract

Leaves of six clonal individuals of Eucalyptus camaldulensis Dehnh. from five Australian locations were compared. Two clones were from Wooramel, WA while single clonal lines were from Dongara, WA, Erudina, SA, Murray Bridge, SA and Silverton, NSW. Principal component analysis of climatic factors for the five locations, derived by BIOCLIM, provided patterns of temperature, radiation and atmospheric moisture, which might be expected to influence the morphological and anatomical features of the leaves. Isozyme analysis indicated that the two Wooramel clones were closely related, but comparable similarity in isozyme pattern was also found between a Wooramel clone and the representative from Murray Bridge. Leaf morphological and anatomical features showed patterns related to the habitat climate of the parent plants, but considerable genetic variation was observable even within a single location. Leaf thickness was generally greatest for clones from the more arid locations and least for clones from the most mesic of locations, but leaf length and width were not associated with any of the climatic factors considered. Thin leaf cuticles were associated with thin leaves. Leaf thickness was determined by the thickness of the internal cell layers, as all clones contained an epidermal and three palisade parenchyma cell layers on both adaxial and abaxial sides. Adaxial palisade layers were thicker than abaxial palisade layers. Stomatal density was not related to leaf dimensions, but clones with the greatest stomatal density tended to have the smallest stomatal pore dimensions. Oil gland density was greatest for leaves of Western Australian clones. Clones from the more arid locations displayed larger chloroplasts. In general, there was a lack of correlation between leaf characteristics and climatic data. Ground water availability, root structure and internal transport of water may have a greater influence on leaf structure than atmospheric demand.