Study On Dispersed Cuticles Of Fossil Plant From The Cisuralian Of Longshoushan In Yongchang,Gansu

At present,the study of the cuticles in paleobotany is very extensive,but it is mainly concentrated in the cuticles in situ,and there are few studies on dispersed cuticles.Starting from the study of the epidermal characteristics of the dispersed cuticles,it is of great significance not only in the analysis of strata,paleoecology and paleoenvironment,but also in the study of large fossils in the same strata.Based on microscopic structure,it is speculated which parent plants belong to,so that the coal seam can be better studied.And the dispersed cuticles also have the advantage of being re-sampling.The fossils studied in this paper were collected from the Cisuralian of the Longshoushan area in Yongchang,Gansu Province.The fossils collected in the field are sedimentary rock containing a large amount of plant debris in the fifth layer of the Shanxi Formation.Due to the particularity of the dispersed cuticles,the treatment method is different from the common plant cuticles.And the entire experiment lasts for several months.The sample was treated with a reagent such as hydrochloric acid and hydrofluoric acid to obtain microscopic structure of the dispersed cuticles,then formed it into a slide and observed and photographed under a Leica DM4000 B biological microscope.Combined with the classification and naming system of the dispersed cuticles summarized by the predecessors,we identified a total of twenty-three types of dispersive cuticles,they were classified into three categories and sixteen sub-categories.Among them,there are eight subtypes in the non-stoma category,eight out of five in the stomata category,and seven out of five in the pore category.Taking the dispersive cuticles as an example,the corresponding complete classification and naming system of the dispersed cuticles was supplemented accordingly.According to the presence or absence of pore and epidermis cells epidermis,a new large class with pore was established,and a sub-category under the non-stoma category.Based on this research,we tried to restore the parent plant of the dispersed cuticles based on the microstructure.The results show that the dispersive cuticles discussed in this paper may be from Cordaites plants and conifers plants.We found the cuticles of the Nematophytes that may be extinct in the Devonian in the large pore class.The creatures under the phylum are considered to be one of pioneers from marine life to land by most scholars.Based on the characteristics of the above-mentioned dispersed cuticles maternal plants,we can basically determine that the climatic conditions of the study area in the Cisuralian should belong to the warm and humid subtropical monsoon forest climate,with dry and wet season changes.At that time,the climatic conditions and geographical conditions were suitable for coal gathering.However,due to the presence of a large number of Nematophytes,the Cordaites and conifers plants that were supposed to be coal-forming materials were decomposed into inorganic substances,which may be one of reasons why no coal seams can be found in this area.