Fossil Gymnosperm wood from Pliocene (Tabriz)

Background and objectives: To reveal plants systematic and phylogenetic evolutionary development of the species, wood identification and wood anatomical descriptions were being considered by Biology researchers every so often. From Palaeobotany point of view there have been done successful researches by studying wood fossils. Petrified woods preserve more extended history of wood habitats comparing to other plants organs. In this study, we identify and introduce fossil woods of Annakhatoon NE of Tabriz region, which were explored from 1:25000 map preparation operations.
Materials and methods: In this study, we put to use stem like pieces to make identifications of the petrified tree stems of the age Pliocene, NE Tabriz.A test specimen was selected from each sample seeming to be in good preservation status at all directions of wood axis, to prepare thin sections. Appearance, size, color and other physical characteristics were recorded and photographs prepared, after transferring the collected samples to the laboratory. we prepared thin sections of all types of transversal, radial and tangential planes, according to specific methods, whereas possible. First of all we cut 1x2x3 cm pieces with their long axis parallel to tree longitudinal axis, removed rough areas, planed and finished. After making a plenty of polishes, the thickness was so lowered around 0.03 mm that the light could pass through the wood thin sections. Thin sections of tangential, radial and cross section were prepared to study microscopically. In the cases where the state of preserving allowed, we studied wood anatomy and the features related to tracheids, ray parenchyma, pits, resin channels and other wood elements employing light microscope. Following IAWA list of microscopic features of Gymnosperms, made the elementary descriptions the identification was completed by comparing data with other petrified woods in collections elsewhere.
Results: Results showed that the structure of fossil sample was the same as Gymnosperms. Growth ring boundaries distinct, transition from early wood to latewood abrupt, ground tissue consists of thin walled tracheids, uniseriate rays abundant, unlikely pinoid bordered pits in cross fields and a few solitary resin canals, were common. The material has been referred to Pinuxylon fossil species of Coniferals at this stage.
Conclusion: Although lack of proper preservation, solitary resin canals, few axial parenchyma, large bordered pits arranged in single rows at radial walls of earlywood tracheids and very likely pinoid pits in the cross fields, show close relation to Pinuxylon genus type. This genus type implies a temperate climate there at that age.