Determination Of DNA C-values And Analysis Of Variation Characteristics Of Bryophytes

DNA C-value is an important biological concept,with many biological and ecology significances.With the accumulation of plant DNA C-value date,the study based on DNA C-value information is also expanding and deepening.So,the expansion of database of plant DNA C-values is usefull for a comprehensive understanding of plant DNA C-value distribution,and its possible significance on biological,ecological and evolutionary.However,the research on the DNA C-values of bryophytes has only just begun.There is no report on this aspect in China.In the present paper,the DNA C-values of 157 species of bryophytes in 44 families were determined.The distribution of measured DNA C-values of bryophytes in different taxa and geographical regions was statistically analyzed,which provided basic data for a more systematic and comprehensive understanding of the biological and ecological significance of DNA C-values.The main results are as follows:1.The method for the determination of DNA C-values of bryophytes using Physcomitrella patens as a standard sample was optimized,The phenomenon of endopolyploidy in the Physcomitrella patens is considered in this paper,To clearly distinguish the peaks of samples and standards,So using the external standard method,Comparison of experiments showed no significant difference between the experimental results of the external standard method and the internal standard method?2.Compare the effect of sample storage time on the results,As a result,10 samples out of 22 samples showed no significant difference,12 samples show significant differences.The time of specimen storage as a whole Will make the second measurement result smaller than the first measurement result.3.The DNA C-values of 157 species of bryophytes in 44 families in Zhejiang,Sichuan,and a small number of school arboretums in China were determined.Among them,12 families and 18 species are liverworts and 139 species of 32 families are mosses.The average DNA C-value of liverworts is 0.542 pg,with a minimum of0.444 pg in Alobiellopsis parvifolius from Mt.Putuo,and a maximum of 0.635 pg in Plagiochila chinensis from Luding County,Sichuan Province.The average DNA C-value of mosses is 0.529 pg,with a minimum of 0.398 pg Macromitrium japonicumcollected Shengsi,and a maximum of 0.860 pg in Rhodobryum giganteum.The present work added new data to DNA C-value database,which deepened people's understanding of the interspecific and intraspecific DNA C-value variations of bryophytes.4.The average DNA C-value of 157 bryophyte species is 0.530 pg,with a maximum of 0743 pg in Leskeaceae,and a minimum of 0.437 pg in Amblystegiaceae,the former is being 1.70 times of the latter.Among the 44 families,25 families have three species whose DNA C-values had been determined.Of these 25 families,17 families have no significant differences in their DNA C-values among them.Significant differences were only determined between some family-pairs fond in Leucobryaceae,Rhytidiaceae,Entodontaceae,Orthotrichaceae,Dicranaceae,Mniaceae,Bartramiaceae and Grimmaceae.5.Using the one-way analysis of variance,the interspecies differences in the C-values of bryophyte DNA in 15 families(more than 5 species were determined in each branch)were analyzed,It can be seen that in addition to the 4 families belonging to the Ptychomitriaceae(P = 0.109),Bryaceae(P = 0.229),Hypnaceae(P = 0.054),and Entodontaceae(P = 0.250),the remaining 11 There was a significant difference in the C-values of the interspecies DNA among families(P < 0.05).6.Of the 157 species of bryophytes that were tested,there were 91 species with more than two habitats or geographical origins.Within these species,one-way analysis of variance was used to compare the differences in DNA C-values between samples from different sources of the same bryophyte species.It can be seen that the variation of C-values in the species within the species shows great differences among species.Among them,18 species of bryophytes had very significant differences in their intraspecific DNA C-values(P < 0.01),accounting for about 44% of the 41 species of bryophytes involved in the comparison;Among them,there were 8 kinds of bryophytes,and there was a significant difference in the C-value of DNA in the species(P < 0.05),accounting for about 20% of the 41 species of bryophytes involved in the comparison;Among them,there were three species with somewhat difference in their DNA C-values(P < 0.1),accounting for ca.7% of the focal bryophytes.There was no statistical difference in the DNA C-values for the remaining 12 species,accounting for about 29% of the 41 bryophyte species.7.Based on the DNA C-values of 91 samples from different geographical sources of 41 species and those of 207 samples in total,the variation patterns of DNAC-values of bryophytes with altitude were analyzed.The C-values of bryophytes are positively correlated with the altitude of distribution,with a slightly high significant level in the taxa with relatively similar genetic background(P < 0.2).