Spore Morphology Of Lycopodiaceae In China,and It's Systematic Significence

In this study,the spores of 44 species belonging to 8 genera of Lycopodiaceae from the Herbarium fern herbarium room(PYU)of Yunnan University were used as materials to carry out spore morphology research through the scanning electron microscopy(SEM).Six selected chloroplast gene fragments(psbA,rbcL,rps4,trnL,trnL-F,trnP-petG)and relevant sequences were downloaded from Genebank.Cipres Science Gateway Maximum Likelihood Model and Bayesian Model are used to jointly construct Lycopodiaceae phylogenetic tree.Spore morphological characteristics are associated with the obtained phylogenetic tree and the systematic relationship among the major taxa of Lycopodiaceae is explored.The main research results are as follows:(1)Although there are some differences in size,surface ornamentation,crack length,radiation area morphology and other aspects of spores taken from different positions(top,middle or base)of the same species' spore leaf spike or main stem,the basic shape,main ornamentation type,polar and equatorial surface morphology of spores,as well as the bulge or subsidence of spore cracks are relatively stable.(2)By observing and comparing the spores of 11 samples of Huperzia serrata and 6 samples of Lycopodium japonicum collected from different regions through optical microscope and electron microscope,it is found that there is no much significant difference among the spore morphology of the same species from different habitats.(3)The spores of Lycopodiaceae are tetrahedron and actinomorphy.The polar view is blunt triangle,triangular circle or nearly circular while some kinds of edge subsidence is truncated.The equatorial view is mostly fan-shaped or elliptical.The extreme red ratio is about 2/3,and the spore size is about(19.23-38.38)29.87 × 22.65(14.1-33.98)? m.Spores have three fissures,which are often convex,sunken or slightly twisted.Spore ornamentation mainly includes Psilate,Foveolate,Ornate,Reticulate,Stripe and Granulate.(4)Based on the morphological observation results of Chinese Lycopodiaceae spores by SEM,which supporting the classification of PPG ?,the Chinese Lycopodiaceae can be divided into 3 subfamilies and 10 genera.Among them,the spore ornamentation of Huperzioideae is cave or holes ornamentation.The spore ornamentation of Lycopodielloideae is pseudoreticular ornamentation.Spore ornamentation of Lycopodioidieae is various with reticular ornamentation,granular ornamentation and rod ornamentation.According to the bulges or sags of the cracks,Lycopodielloideae can be distinguished from the other two subfamilies.The cracks of the Lycopodielloideae have obvious or slight sags,while the cracks of the Huperzioideae and Lycopodioidieae are bulges.(5)According to the sequence of 6 chloroplast gene fragments(psbA,rbcL,rps4,trnL,trnL-F,trnP-petG),a phylogenetic tree of Lycopodiaceae can be constructed.with Selaginellaceae and Isoetaceae as out groups.In the obtained phylogenetic tree,the entire Lycopodiaceae constitutes a monophyletic group,which consists of 3 main branches,and each branch corresponds to 3 subfamilies,namely Huperzioideae,Lesser Lycopodielloideae and Lycopodioidieae.The three subfamilies can be further divided into 16 genera,all of which are well supported except Huperzia.(6)Based on the SEM observation results of spore morphology,supplemented by morphological observation,and referring to the constructed systematic tree based on chloroplast gene fragments,this paper also preliminarily compiled the taxonomic key list of three subfamilies and ten genera of Lycopodiaceae from China.