Study On Interspecific Relationships And Geographic Variation Of Ranunculus Cantoniensis Complex

The Ranunculaceous Genus Ranunculus includes 2000 species, 122 species are distributedin China. Of which Ranunculus cantoniensis complex is a taxon group which morphology aresimilar. And they have the characteristics of wide distribution, long evolution history,complicated habitation, big plasticity in morphology, high frequency of ploidy, vegetative orsexual reproduction and be in presence along with human's activity.In view of their longevolutionary history, diversity in growth habits, as well as polyploidy, abundant variation andgenetic diversity. Study on formation of Ranunculus cantoniensis complex by fluorescence insitu hybridization (FISH), TmL-F and karyotype was performed, the mechanism of itsformation was analysed; The morphological and karyotyping characters were studied at thepopulation level in R.cantoniensis complex and its allied species from 8 provinces or city inChina. The main research fruits go as follows:â… R.cantoniensis complex and its allied species are often distributed in the areacharacterized by man's activity. Especially in the newly reclaimed badlands, they usuallybecome the first occupant. Their ecological environment types are in diversity and can beclassified into 4 types which are hill grassland type(grass land and roadside), plain meadowtype(streamside, patty field), seashore bottomland type (rivershore, reservoirside) andinterstitial-meadow of farmland and woodland type(forest margin, ridge of field). In thepolyploidy species, both of the case which low ploidy species is mixed with that of highploidy, such as R.repense ,and the case which low ploidy species is distributed in the relativelyhumid environment, while high ploidy one is present in the arid area, such as R.sieboldii,exist.â…¡The results based on the datum of moleculacy disclosed that another parent is mostpossibly R.silerifolius var.dolicathus but not R.chinensis,except for R.silerifoliusvar.silerifolius,in the interspecific hybrid origin of R.cantoniensis. It also implied thatR.silerifolius var.dolicathus is female parent, while R.silerifolius var.silerifolius is male parentof R. cantoniensis.â…¢The R. cantoniensis complex is made up of R. cantoniensis, R.silerifolius var.silerifolius,R.silerifolius var.dolicathus, R.chinensis and R.sieboldii. and it is probable that the members inthe complex became related through the genome called "short m-type". It is a complex of beingunder mature phase.â…£The results from the cluster analysis by 22 morphological or 7 karyotypic charactersshowed the interspecific relationship among the species in R. cantoniensis complex and its alliedspecies are almostly identical to that of the classically morphological analysis. They can reflect the relationships among the species in R.cantoniensis complex and its allied species in greatdegree, it means that the choice of these characters are reasonable and effective.â…¤In the population of R.cantoniensis complex and its applied species: biggishdifferences exist in 22 external morphological traits such as length and width of basal leaf,length and width of petal and so on due to affection by genetic differentiation. Of which thebiggest variation range represent in different characters according to different species, thefewest variation range emerge in the ratio of length to width of petal and sepal,as well as thedegree of flat of achene.â…¥Among the populations of R.cantoniensis complex and its applied species:Differentgeographical population have different morphological characters resulted from affection bydifferent geography environment; Meanwhile, the stable characters i.e. ratio of length to widthof petal, ratio of length to width of sepal and degree of flat of achene are increasing with theincrease of latitude in some species, while they are increasing with the increase of longitude inother species; it showed that the degree of morphological variation due to affection by differentgeography environment is different and the complex posses high adaptation to environment. Inaddition, whether the difference among populations is considerable or not is not internallyconnect with the variance index in a species.â…¦The results from the main components analysis on datum of morphologicalcharacters in R.cantoniensis complex indicated that different species in the complex hasdifferent main elements which result of the morphological variation, but the main elementsshare the common characteristics:they all belong to vegetative apparatus or absolute value ofreproductive apparatus such as the width of the first and second turn split of basal leaf, thewidth of stem leaf in R.silerifolius var.silerifolius; length or width of petal and length or widthof sepal in R.silerifolius var.dolicathus; tall, length of leafstalk of basal leaf and the width ofsecond turn split of basal leaf in R. chinensis and length or width of petal in R.sieboldii.â…§The analysis based on karyotype showed that the index of karyotype asymmetryincreased,and the total genome length decreased along with the increase of latitude inR.cantoniensis and R.silerifolius var. silerifolius; while they do so along with the increase oflongitude in R.chinensis.The results are almost consistent with those concluded frommorphology data set.Combining them, we can speculate the possible evolution route ofR.cantoniensis complex and its allied species in China is from YunGui altiplano and HengduanMountains to Eastward and Northward area according to the increase of longitude andlatitude, respectively.â…¨The R. cantoniensis complex is an advanced taxon in the Genus Ranunculus.