Intra- and Interpopulation Variation of Leaf Life Span in Rhododendronledebourii Pojark. and Rh. dauricum L. (Ericaceae Juss.) and Its Environmental Determination

Abstract

Twenty cenopopulations of Rhododendron dauricum and Rh. ledebourii, two closely related and morphologically hardly distinguishable species, have been studied with respect to one of the most significant taxonomic features, the life span of leaves on the shoot. The correlation of this feature with other morphological characters of plants and climatic conditions in the species habitats has been evaluated, and its intra- and interpopulation variation has been analyzed. In both species, leaf life span has been found to increase with an increase in elevation above sea level and annual precipitation. Significant differences in leaf life span between conspecific populations and the absence of significant differences between species have been revealed.