Classification Significance Of Phytolith Morphology And Microelement Composition In Bamboo Leaves

Phytolith analysis is widely used in plant classification,Phytolith formation mechanism,archaeology and paleoenvironment reconstruction,among which the study of Phytolith morphology,size and combination is more in-depth.However,the study on the chemical composition of phytoliths is insufficient,and the electron probe microanalysis of the chemical composition of different forms of phytoliths is rarely carried out.Bamboo is widely distributed in China.It is a kind of economic crop with important ecological value.It has a wide range of uses and is closely related to our life.Because the vegetative growth period of bamboo is very long and the flowering period is uncertain,it is very difficult to identify species and genera.The study of Phytolith species identification is of great significance to the reconstruction of paleoenvironment and the identification of archaeological remains.In this paper,the phytolith morphology,assemblage and chemical composition of20 species of bamboo leaves in three species and genera of Bambusoideae were analyzed.The taxonomic significance of Phytolith morphology,size and assemblage of different species and genera was studied,and the taxonomic value of Phytolith chemical composition of bamboo was explored.The main results are as follow:(1)The assemblages of phytoliths in different species were different,and the oblong concave saddle and the saddle/bilobate shape were the two morphological types with the most abundant The content of saddle/bilobate shape phytoliths in Dendrocalamus is much higher than that in in Bambusa and Phyllostachys.The abundance of phytoliths in samples was analyzed by systematic cluster analysis.The results showed that the relative assemblages of all phytolith morphotypes could classify bamboos at the level of genus.The results showed that phytolith morphological combination could classify bamboo at genus level.The morphological parameters(length,width)of oblong concave saddles in different species and genera,and the size of oblong concave saddle has certain taxonomic significance at the genus level.(2)Phytolith carbon content in different bamboo genera was different,and the phytolith carbon content in different bamboo species was also different.According to the study of bamboo ecotypes,the phytolith carbon content in three ecotypes of bamboo was scattered bamboo(Phyllostachys)>clustered bamboo(Dendrocalamus and Bambusa).(3)Three methods of direct analysis of C(DAC),Fix-C and not analysis of C(NAC)were used to analyze the chemical composition of phytoliths in leaves.The results showed that direct analysis of C(DAC)was not feasible.In order to accurately compare the chemical composition of different forms of phytoliths,the data of not analysis of C(NAC)was used to analyze.(4)EPMA analysis of bamboo leaves showed that the phytoliths contained Si,Na,Al,Mg,Ca,Mn,Cr,P,K,Fe and other elements.According to the specific gravity of phytoliths,the weighted average values of Phytolith chemical composition were calculated.It was found that the average values of Si O₂and total in different genera were significantly different(Phyllostachys>Dendrocalamus>Bambusa),we do not yet know what the influencing factors are.The chemical composition of phytoliths in different forms of the same bamboo is different.Electron probe chemical composition can not distinguish bamboo species and genera,but can distinguish bamboo subfamily from millet subfamily,which may be related to the similarity of plant growth environment.This study proves that the chemical element composition of electron probe has certain classification ability.It can provide reference for further study on chemical composition and classification of phytoliths.