Morpho-Molecular Study on some Taxa of Apocynaceae Sensu Lato

Abstract

Apocynaceae sensu lato (s.l.) is treated as distinct family in some taxonomic systems while in others is treated as two separated families viz. Apocynaceae sensu stricto (s.s.) and Asclepiadaceae. So the main objective of the present study was to adopt one of the two views. The morphological characters viz. whole plant, lamina vein architecture and lamina epidermal characters of 20 wild and ornamental species were examined using LM and SEM. The data were numerically analyzed to detect the phenetic relationship among the studied species. DNA barcoding based on the sequencing of rbcL gene was cladistically analyzed to detect the phylogenetic relationship among the studied species. The generated phenogram showed a clear separation of two subseries; one of them belonged to Apocynaceae and the other with the remaining taxa belonging to Asclepiadaceae. The obtained cladogram showed that all of the studied species were divided into four lineages. It is concluded that the phenetic analysis supports the treatment of Apocynaceae s.l. as two distinct families; Apocynaceae s.s. Asclepiadaceae contrary of the phylogenetic one that supports the treatment of Apocynaceae s.s. and Asclepiadaceae as one family (Apocynaceae s.l.) with four subfamilies viz. Apocynoideae, Rauvolfiodeae, Asclepiadoideae and Periplocoideae.