A Study On The Anatomy Of Hairs And Scales In Ferns

Scales, a unique morphological character of ferns, play a very important role in the taxonomical studies. Since F. O. Bower proposed that scales originated from epidermis hairs in 1923, botanist generally believed that scales evoluted from simple hairy structure to complex lamellar structure. For the attaching ways of scales, Tsutsumi et al. infered stalked scales originated from basifixed ones based on molecular evidences in 2008. However, because of the lack of systemic anatomical data, the use of scale was few in phylogeny analyses of ferns. The evolution trend of scales is still unclear. Systematical anatomy on the scales of ferns was carried out through large-scale sampling, morphological features of scales in ferns were described detailedly in this thesis. Contrasted to molecular tree of ferns, the evolution of scales and their adaptation to ecological factors were discussed here.We chose 345 species of ferns as our study materials, which belonged to 33 families 12 subfamilies and 119 genus. We observed the scales by means of integrated microscope, then we described the morphological characteristics and measured the morphological datum of them, after that, we analyzed the attaching ways, columns of cell of scales and living environment styles and bodies styles of ferns combined with phylogeny tree by R software.The major results of this study are as follows:1) The changes of some genera and families in molecular system, including combination of C heiropleuriaceae and Dipteridaceae, putting Histiopteris into Dennstaedtiaceae, Loxogrammaceae into Polypodiaceae, Taenitidaceae into Pteridaceae, combination of Parkeriaceae and Acrostichaceae, putting Adiantaceae into Vittarioideae, Stenochlaenaceae into Blechnaceae, Monomelangium into Diplazium, Cyclopeltis into Lomariopsidaceae, Quercifilix into Tectaria, Pyrrosia into Platycerioideae, Loxogrammaceae into Polypodiaceae, Pleurosoriopsidaceae and Grammitidaceae into Polypodioideae, were not supported by the morphological characteristics of scales. Changes of other families and genera in molecular system, such as Pteridiaceae, Hypolepidaceae and Monachosoraceae were combined into Dennstaedtiaceae, Sinopteridaceae and Hemionitidaceae were divided into Pteridaceae et al.. In addition, It was not supported by the morphological characteristics of scales about the position change of some species, such as Microsorum fortune was put into Neolepisorus.2) Hairy scales and lamellar scales alternated for many times in the process of fern systematical evolution. Hymenophyllaceae, Dennstaedtiaceae(except for Histiopteris), Marsileaceae, Salviniaceae, Schizaeaceae, Gleicheniaceae(Scales on the rhizome), Lygodiaceae, C ibotiaceae, Dicksoniaceae, Taenitis, Cheiropleuria, their scales present one column hairy; Dipteris and C yatheaceae, Lindsaeaceae, Pteridaceae, Athyriaceae, Blechnaceae, Hypodematiaceae, Thelypteridaceae, Dryopteridaceae, Tectariaceae, Aspleniaceae, Onocleaceae, Nephrolepidaceae, Lomariopsidaceae, Oleandraceae, Arthropteridaceae and Polypodiaceae, their scales are many cell columns lamellar structure. This illustrated that lamellar scales are more suitable to protect plants in dry environment.3) The attaching ways, including basifixed scales and stalked scales, alternated for many times in the process of fern systematical evolution, and stalked scales appeared near the Gleicheniaceae clade, and concentrated exsit in eupolypods, this is different from the suggestion of Tsutsumi et al., which was the divergence time of stalked scales differentiated in eupolypods. What was more, there should be multiple differentiation when stalked scales originated from basifixed ones.