Phytolith Morphological Characteristics Of Fagopyrum In The Karst Area Of Southwest China

Phytolith is formed in plant cells or intercellular spaces,and phytolith morphology has obvious indicative significance of plant species.Therefore,phytolith morphology has applications in many fields such as archaeology,paleoclimate reconstruction,paleovegetation reconstruction,plant classification and so on.Fagopyrum is an important grain in China and plays an important role in social and economic development.At present,there are still obvious disputes on the origin,evolution and species classification of Fagopyrum,and new evidence is urgently needed for in-depth study.In this study,6 species of 16 Fagopyrum varieties,including F.esculentum,F.tataricum,F.Tatari-cymosm,F.cymosum,F.megaspartanium and F.pilus,were planed in the Fagopyrum planting base in Xixiu,Anshun,Guizhou Province as the research object.Analysis methods such as one-way ANOVA and Pearson were used.To find the change rule of Fagopyrum phytolith's morphological types,the proportion and size of main types and the changes under different species,varieties,organs and growth stages.The correlation between proportion of phytolith,morphological size and soil physical and chemical factors was discussed.Combined with the principal analysis of phytolith morphological characteristics and species classification of Fagopyrum,this paper systematically introduces the morphological characteristics of Fagopyrum phytolith,so as to provide favorable evidence for its origin,evolution and systematic classification in the future.The main results are as follows:(1)A total of 16 phytolith types were observed in Fagopyrum:amoung which round,short rod,multilateral,lanceolate,square,rectangular,elliptic and round-lanceolate were the main phytolith types in Fagopyrum.Cuneiform,saddle,elongate granulate,pherical-spinulose,rondel,bilobate,Y-shaped and elongate were the occasional phytolith types in Fagopyrum.Among the types of phytolith,the proportion of phytolith in round type and short rod is relatively large,especially the round type,accounting for about 50% of all types.The phytolith of Fagopyrum are small and medium-sized,and their size is less than 20 ?m,and most types are around 10 ?m.The round-lanceolate has not been found in other plants,but it was found for the first time in Fagopyrum.Therefore,this shape may be the first discovery in known reports,and it will be of great significance to the identification of the phytolith morphology in Fagopyrum.(2)In the proportion of phytolith in Fagopyrum,there was a significant difference between F.cymosum and the other species.The proportion of elliptic in F.tatari-cymosum 2012-1206 was significantly higher than the other two varieties.The proportion of round-lanceolate in root was significantly higher than stem and leaf.The proportion of short rod in root and stem was significantly higher than leaf.The proportion of round and elliptic was significantly higher in May than in July.The proportion of short rod and rectangular was significantly higher in July than in May.(3)The length and width of multilateral,lanceolate and square in F.cymosum was significantly higher than the other species.The length of elliptic in F.esculentum was significantly higher than F.pilus.The size of phytolith changed significantly among different varieties.In different organs,only the length and width of round-lanceolate showed significant differences.In different growth stages,the length and width of round,multilateral and elliptic were significantly higher in May than in July;the width of lanceolate was significantly higher in May than in July;the length of rectangular was significantly higher in July than in May.(4)There was no significant correlation between soil bulk density and TP about the proportion and size of phytolith,and there was no significant correlation between rhizosphere soil chemical factors and size of phytolith.SOC,Si and p H are the key factors affecting the proportion and size of phytolith.In addition,soil moisture content,TN and field capacity also affect the proportion and size of phytolith.(5)The size of phytolith about round,short rod,elliptic,square and round-lanceolate,and the proportion of phytolith about elliptic,short rod,lanceolate and round-lanceolate are important indicators for Fagopyrum species classification.The size of phytolith about short rod,lanceolate,rectangular and round-lanceolate,and the proportion of phytolith about multilateral,short rod,round,lanceolate and elliptical are important indicators for Fagopyrum variety classification.It has important guiding significance for identifying different species of Fagopyrum.