The Study Of Spacial Distribution And Molecular Evolution Of Lichen From Different Altitudes In Urumqi River

The lichen has a widely geographical distribution in the world. It is a symbiotic association which is constituted by fungi and algae or cyan bacteria. The biological character of lichen is reflection of the essentiality of fungi within the symbiotic association. Therefore, lichen has been named lichen-forming fungi. Very little is known about the distribution and molecular characteristic of lichen in the Urumqi River, Xinjiang province, China. Based on more than 150 specimens collected from the Urumqi River, comprehensive study is carried on distribution, life forms and the distribution patterns of group I intron from different altitudes. The major results are as following:1. 35 species belong to 14 genera and 10 families. Among them, one species is newly recorded from China, Rhizoplaca haydenii. It indicated the numbers of mutual species are not much more than other regions. The stress resistance of lichen is reduced at extreme environment.2. The mutual genera and species are compared between Urumqi River and other 5 regions of China (not including Tianshan Mountains), we found the number of mutual species are not much more. The most high similar index is 17.14%, the number of mutual species are six species, which is found in Sai Hanwula national nature reserve zone of Inner Mongol ian autonomous region. It indicated the similarity of lichen species between Urumqi River and other 5 regions is very low. And it showed that the particularity of lichen distribution is very worth to study at extreme environments.3. The arctic species is vantage species in Urumqi River. The characteristic of Eastern Asian is notable and this area has some relationship with flora of circumpolar arctic-alpine species. This characteristic is related with geography location and climate characters of Urumqi River. 4. The life forms of species in the region are most epopetria, crustiform, they are 82.85%. The number of mutual species are not much more than other regions and most crustiform for higher water evaporation, higher drought indexs, lower water content in soil. The soil-epipetria lichen is 5.71%. Therefore, we thought the influence of climate to lichen distribution is much more than soil.5. The characteristics of the vertical distribution are found. Under the altitude of 3000m, the number of species is sparse, only 5 species. The number of species is increasing, owing to adaptation to the environment above 3000m. The species are fertile between 3200m-3500m, including 35 species. The amount of species comparatively reduces to 12 species above 3900m. The distribution of lichen species Xanthoria elegans, Candelariella medians, Rhizoplaca peltata, Umbilicaria proboscidea and Umbilicaria hypococcinea is very widely. They distribute between 4100m-2200m. The distribution of lichen species Evernia divaricata is very narrow. It is only distributes between 3900m-3600m. This distribution of lichen species at different altitudes is related with stress resistanceof lichen.6. We studied the molecular evolution of lichen at extreme environments used the distribution patterns of group I introns at different altitudes. We found the figment of primers NS18 and NS19 region come from 3700m sample is bigger than other altitudes in Rhizoplaca melanophthalma. The number of group I intron from 3800m, 3700m samples is more than the samples from 3600m, 3500m and 3200m in Rhizoplaca peltata. In Rhizoplaca chrysoleuca, the samples from 3700m and 3500m have most group I intron number. In Evernia divaricata and Allocetraria madreporiformis, the most number of group I intron is found in 3700m samples. In Lecanora rubina, the most number of group I intron is found in 3600m samples. The number distribution of group I intron is vertical distribution only in Xanthoria elegans. The most number of group I intron is found in 3800m samples. And we thought the number of group I introns are not always adaptation mechanism to extreme environment.7. Though studing the distribution patterns of group I introns at different altitudes, we found the distribution pattern of group I intron has not specific within species or among different species at different altitudes from the same region.8. When we studied the revolution relationship with species, our analysis reveal the distribution patterns of group I intron did not show convincing evidences to prove phylogenetic relationship among within species.9. We found the evolution relationship of the samples having identical distribution patterns of group I intron is closer to each other than to others in the species. Therefore, we thought the distribution patterns suggest that the group I introns in these species are in the equilibrium of "insert-delete". The intron less loci would acquire introns from their intron harboring alleles by sexual reproduction, which suggest that the insertions distribution patterns in a recombination population would be the same. The different distribution patterns of group I intron were found in the different monophyletic groups. This suggests that no gene exchange occurs within the populations and the isolation mechanism has established.