Infra-specific variation of Acer cappadocicum (Sapindaceae): morphological and molecular approaches

Abstract

Besides Quercus, Acer L. genus is the largest tree genus in the Northern Hemisphere and consists of about 124–156 species. High morphological and molecular variability has led to infra-specific complexity within most species of this genus. In Iran, the Acer cappadocicum subsp. cappadocicum Gled. is distributed in eastern to western parts of the Hyrcanian forests. In this study, three leaf-morphotypes in A. cappadocicum Gled. were identified during sampling in a forest located in the Hyrcanian region, leading to obscuring taxonomic situations of this taxon. Against this backdrop, the present study was performed to clarify intraspecific situation of this valuable tree using both macro-/micromorphological and molecular approaches. Forty-five plant samples of A. cappadocicum were randomly selected within nine geographical regions of four provinces in Hyrcanian forests of Iran. Internal transcribed spacer (ITS) (for eight individuals) and inter-simple sequence repeat (ISSR) molecular markers (for 45 individuals) were used along with the epidermal scanning electron micrograph (SEM) of the leaf epidermis. Considering the obtained results, acceptance of the expected lower taxa in A. cappadocicum ssp. cappadocicum in north of Iran could not be supported by molecular evidence. Results of the study indicated no correlation between variations in leaf-morphology, ISSRs, and ITS. However, there are two main clusters in ITS tree without discrete morphological characters showing differentiation and variability in ITS region within this species. This subspecies was compared also with other subspecies.