Exploring the application of anatomical and micro-morphological structure of leaf in identification and separation of Silene sections and species (grown in the north-east of Iran)

Silene belongs to Caryophyllaceae family which has more than 700 species all over the world, with 98 species, and 14 sub-species growing in Iran. Considering the difficulty of identifying Silene species according to morphological properties and the lack of their separation, the present study investigated the anatomical structure of the leaf in 10 species and sub-species belonging to four sections (Sclerocalycinae, Auriculatae, Melandriformes, and Conoimorpha) which grow in Mashhad and its countryside. Cross-section (12-Micron-thick) cuts of the leaf were prepared and stained by Safranine-Fastgreen. After separation, under-leaf epidermis was stained with Metilen blue and was studied using LM (with 100, 400, and 1000 magnification). The upper epidermis was studied by means of SEM (with 500 and 1500 magnification). Various anatomical properties including: the condition of mesophyll, the diameter of palisade and spongy mesophylls, the presence or absence of pilose and its shape, the density and type of stomata, and the number and shape of epidermis cells were used for separating the species. The results indicated that there was a difference between the arrangement and compression of palisade and spongy mesophylls among glabrous and pubescent species. Additionally, in Conoimorpha and Melandriformes sections in which the plants are one- and two-year old, the condition of mesophyll is dorsiventral, whereas in Sclerocalycinae and Auriculatae sections which have older plants, the condition is isolateral. The type of stomata was diacytic in some species and both diacytic and anisocytic in some others. The SEM analyses also revealed differences in the shape and density of piloses.