Study On The Breeding System Of Viola In Eastern Liaoning In China

Viola,a ephemeral plant in early spring,is a group with many species,wide distribution and large variation in Violaceae.It is a large genus distributed worldwide,with more than 500 species.114 species are produced in our country,most of which are distributed in the northeast,north China,and provinces south of the Yangtze River Basin.Among them,there are about 40 species in the northeast and more than 30 species in the eastern Liaoning.Viola plants have typical species with a dimorphic mixed mating system,that is,two kinds of flowers with completely different morphologies appear at different periods of the same individual or at the same periodopen flowers(chasmogamous,referred to as CH)and closed flowers(cleistogamous,Referred to as CL).It is a good material for studying the mixed breeding system of plants.This article uses 11 common species of Viola in the Northeast as the research object.By observing the species with closed flowers,comparing it with the grouping of Viola in the Flora Whether in the same group,molecular identification of all species,analysis of the genetic relationship between the species with closed flowers and the species without closed flowers,observe whether there is regularity.The experimental results are as follows:1.Among the 16 species of Viola collected in this experiment,there were six species of cleistogamous,all of which belonged to the Subgen.Viola under the genus Viola of Violaceae,but did not belong to the same group.Among them,Viola philippica,Viola mandshurica,Viola prionantha and Viola lactiflora belonged to the Sect.Adnatae(W.Beck.)C.J.Wang.Viola hamiltoniana belongs to Sect.Bilobatae(W.Beck.)Juz;Viola acuminata belongs to the Sect.Trigonocarpae Godr.It is very likely that there is a certain correlation between the CH-CL system and genetic relationship of Viola.In addition,due to various external reasons such as poor living environment and difficult pollination in the late stage,Viola has a certain impact on the mating system during the late species differentiation.As a result,more Viola species have made natural selection and evolved cleistogamous for self-pollination to ensure the continuation of future generations in order to achieve more efficient inheritance.2.The observation showed that the cleistogamous of Viola philippica,Viola acuminata,Viola hamiltoniana were more in number,while the cleistogamous of Viola prionantha were less in number.Moreover,varieties with large number of cleistogamous(such as Viola acuminata)showed higher growth density,often clustered growth,and smaller individual difference in population.Varieties with less cleistogamous(such as Viola prionantha)had lower growth density,and each individual grew independently,and the individual differences in the population were larger.The reason for this might be that during the seed maturation period of CL flowers and CH flowers,the force generated by capsule dehiscence would eject the seeds,while the seeds of CL flowers were not as high as the seeds of CH flowers,so the seeds of CL flowers would be scattered near the plants,while the seeds of CH flowers would pop up a long distance.As a result,the seeds produced by CH flowers would weaken the competition among species and the produced offspring might have relatively rich genetic diversity,which might be the impact of this special breeding system on the genetic structure of the population.3.According to the results of clustering analysis,the 11 species of viola could be divided into 5 groups,with Viola variegata,Viola lactiflora and Viola tokubuchiana as one group,Viola philippica,Viola mandshurica and Viola prionantha as one group,and Viola diamantiaca,Viola hamiltoniana,Viola orientalis,Viola acuminata and Viola collina as one group.from the genetic distance,Viola orientalis was the farthest from other species,while in the group of flora of china,Viola orientalis was the Sect.Erectae(W.Beck.)C.J.Wang in the Subgen.Chamaemelanium(Ging.)Juz.,and the other 10 species were all grouped in Subgen.Viola Among the six species of viola with cleistogamous,Viola philippica,Viola mandshurica and Viola prionantha are grouped into one group,while the other three species of Viola lactiflora,Viola hamiltoniana and Viola acuminata are not grouped in the same group,which is consistent with the observation results of viola plant ecology.Viola has evolved for dozens of times up to now,which probably indicates that the species differentiation process of Viola occurred before the emergence of CH-CL system,in which some species mating system and species differentiation were accompanied,and this special mating system had certain influence on the population genetic structure in the later stage.In the later stage of species evolution,other species of Viola were influenced by external environment and other factors,which evolved in order to ensure stable inheritance and continuation of offspring.