Analysis Of Physiological Characteristics And Genetic Diversity On Herpetospermum Pedunculosum(Ser.) Baill Collected From Different Altitudes In Tibet

Herpetospermum pedunculosum(Ser.)Baill mainly distributed in Tibet,Yunnan and Sichuan plateau of China.Dry and mature seeds are rich in medicinal value which is widely used as a Tibetan medicine.However,H.caudigerum has become one of the endangered species due to a large number of mining.In this work,the physiological characteristics of H.caudigerum at high altitude in Tibet and its genetic variation in nuclear DNA and chloroplast DNA were studied.These results can provide a theoretical basis for rational exploitation and protection of germplasm resources of H.caudigerum(Ser.)Baill.Here,the leaf shape among samples was incised along with increased altitude.And stomatal size and respiration function showed a decrease tendency.At the same time,high altitude has an effect on photosynthesis function of plant.Compared with high altitude samples,the lower altitude has a small impact on populations in growth and development of H.caudigerum.In addition,high altitude caused a decrease in total chlorophyll content.ABA,proline and soluble sugar were increased accordingly,whereas ANTH was decreased.Increased altitude induced in increased activities of SOD,APX,DHAR,MDHAR and GR.Total glutathion content,total ascorbate content and ASA/DHA ration were increased with increased altitude.A total of 426 fragments were scored across all the 10 AFLP primer combinations,256(60.7 %)were polymorphic and could differentiate the populations analzsed.The dendrogram revealed that different altitude populations have high genetic diversity(Ht=0.156,Hs=0.111,Gst=0.287 and Nm=1.618).The averages of number of alleles(Na),effective number of alleles(Ne),Nei's genetic diversity(H)and Shannon's index(I)were 1.352,1.188,0.111 and 0.168,respectively.The analysis of genetic structure showed significant.The cluster result showed that 70 individuals were grouped into 3 major clusters.The results showed that the genetic similarity between the populations was 0.857,while the Mantel test was not significant.The AMOVA analysis showed that the population variation mainly came from the intergroup variation.Twenty eight parsimony informative sites and one hundred and two INDELS were identified based on the combined fragments(696bp).Five trn L-trnF-300 haplotypes,three trnL-trn F-396 haplotypes were identified among the 4 H.caudigerum samples,respectively,and seven haplotypes were identified based on the combined fragments.Non-coding region trnL-trn F-300 exhibited highest polymorphism with the most number of haplotypes,the most abundant haplotypes(gene)diversity and nucleotide diversity.Non-coding region trn L-trnF-396 exhibited the most variant of haplotypes diversity and the highest standard deviation of haplotype diversity.Values of haplotype(gene)diversity(Hd)and nucleotide diversity(Pi)of 4 H.caudigerum samples from different attitude in Tibet are 0.748 and 0.019,respectively.The results of AMOVA showed that the variation ratio among populations was 96.7%,while the variation rate in the population was 3.21% and P < 0.05 was significant.Tajima's test which showed all Tajima's D values are statistical significant is combined with and Pairwise mismatch indicated that natural selection has an effect on mutations of this fragment.The network constructed with Median-Joining network calculation exhibited that H1 has a far relationship with other closer haplotypes.