Study On The Genetic Relationships Of Guihaia And Relative Species

Guihaia belongs to Arecaceae,Coryphoideae,Thrinacinae.It was a new genus established by John Dransfield in 1985 on the basis of morphological characteristics such as leaf lobe folding,flower structure and fruit shape.At that time,there were only two species of Guihaia(G.argyrata and G.grossifibrosa).Before the establishment of Guihaia,the first discovered G.grossifibrosa was classified as Rhapis,and G.argyrata was classified as Trachycarpus.In recent years,new species of Guihaia have been discovered.In 2018,we found G.heterosquama in fuling district,chongqing.At present,there are few studies on the genetic relationship between species and related genera of Guihaia,the genetic evidence is still needed for the classification of new species,G.heterosquama,and the establishment of Guihaia is only based on morphological characteristics.It is of great significance to explore the genetic relationship among Guihaia and its related plants on the molecular level.In this experiment,the morphological characteristics of Guihaia were compared,and two kinds of molecular markers,ISSR and SCoT were used to analyze the genetic relationship of 10 species,40 plants of Guihaia and relative species.This experiment aims to provide theoretical support for the classification of new species,G.heterosquama from two aspects of morphology and molecular biology,and also discuss the rationality of establishing Guihaia from the molecular level,providing reference for the study of system evolution,rational protection,effective utilization of Guihaia.The main findings of this study are as follows:1.The new species,G.heterosquama was different from the three known species of this genus.It had soft and separated leaf sheath fibers,two different types of scales on leaf blade abaxially,glabrous hastula at apex of petiole,glabrous,scaleless sepals and petals,a distinct pistillode in the male flower.2.Based on single factor and L₁₆(4⁵)orthogonal design,a suitable ISSR-PCR and SCoT-PCR reaction system of G.heterosquama was eatablished.3.According to the variation of Nei's genetic distance and genetic similarity coefficient among10 species,G.heterosquama,G.argyrata and G.grossifibrosa were clustered together,which were separated from other related genera.4.Based on the morphological and molecular marker results,the new species,G.heterosquama belonged to Guihaia.5.The results of molecular markers showed that G.argyrata and Trachycarpus,G.grossifibrosa and Rhapis were far from each other,Guihaia were clusted into one group,separating from Trachycarpus and Rhapis.The research results initially supported the idea of establishing Guihaia based on morphological characteristics.