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资助项目
GST, P < 0.05) were exhibited by this species. The SAMOVA revealed seven diverging groups of related chlorotypes, six of them had distinct nonoverlapping geographical ranges: one in the northeast comprising 10 populations, a second with a southeast distribution comprising 22 populations, and the remaning four groups comprising 15 populations located in the west part of the species’ range along different river valleys. The genetic clustering of populations into three regions was also supported by analysis of molecular variance, which showed that most genetic variation (82.43%) was found among these three regions. Two clusters were distinguished by both phylogenetic analysis and genealogical analysis of chlorotypes, one consisting of chlorotypes from the western region and the second consisting of those from the eastern region. Significant genetic differences between the two regions might be attributed to vicariance and restricted gene flow, and this vicariance could be explained by the physical environmental heterogeneity on each side of the Tanaka-Kaiyong Line. Following the uplift of the Tibetan Plateau, the reorganization of the major river drainages was primarily caused by river separation and capture events. These historical events could change the distribution of S. davidii from fragmented to continuous (Upper/Lower Jinshajiang and Yalongjiang/Daduhe), and from continuous to fragmented (Nujiang and Jinshajiang/Honghe). However, spatial and temporal patterns of phylogeographic divergence are strongly associated with historical disjunction rather than modern drainage connections. Moreover, the following north-south split in the eastern region and effective isolation with their genetic diversity were essentially modelled by genetic drift. The higher chlorotype richness and genetic divergence for populations in western region compared with other two regions suggests that there were multipe refugia or in situ survival of S. davidii in the Himalayan-Hengduan Mountain region. Fixation of chlorotypes in the northeastern region and near fixation in the southeastern region suggest a recent colonization of these areas. We further found that this species underwent past range expansion around 37-303 thousand years ago (kya). The southeastern populations likely experienced a demographic expansion via unidirectional gene flow along rivers, while northeastern populations underwent a more northward expansion, both from initial populations (s) (21, 22, 23) preserved on eastern refugia (Jinshajiang). This process might have been accompanied with a series of founder effects or bottlenecks making populations genetically impoverished. 3. Phylogeographic analysisbased on nuclear sequence，We sequenced the nuclear (ncpGS) region in all populations sampled, recovering 23 nuclear haplotypes. Compared to cpDNA, both NST (0.470) and GST (0.338) were relatively lower, but NST was also significantly larger than GST. 37.10% of the total variation was distributed among regions which was much lower than that shown by chlorotypes. Thus, more extensive distribution of nuclear haplotypes was exhibited across the geographical range instead of the strong population subdivision observed in chlorotypes. Similarly to the chloroplast data, we found that genetic differentiation of nDNA was positively correlated with the geographical distance, but the increase in the geographical distance between populations did not increase the genetic differentiation of nDNA as rapidly as that of cpDNA. These contrasting levels between the chloroplast and nuclear genomes of S. davidii are likely due to limited gene flow of cpDNA by seeds vs. the extensive gene flow of nDNA by wind-mediated pollen in the population history. We also determined from nuclear markers that haplotype diversity was reduced in the southeastern and northeastern regions due to the loss of rare haplotypes in western region. This reduction of gene diversity is also a signature of founder events or recent bottleneck during post-glacial colonization. However, nuclear diversity within populations remains high. This provides evidence that regionally pollen flow might be sufficiently high to blur the genetic identity of founder populations over a reasonably large spatial scale.3. Relationships among three varieties，The phylogenetic analysis identified two phylogroups of chlorotypes, corresponding to S. davidii var. davidii and var. chuansinesis. The former was distinguished by the abscence of predonminant nuclear haplotype H1 of the latter. The monophyletic group of chlorotypes in var. davidii and var. liangshanesis showed their relatively close relationship. And their genetic divergence from the third variety appears to be relative to their slight morphological difference in leaf size and the divergent environmental niche spaces they occupy. Thus, the observed differences in morphological characters between var. chuansinesis and other two varieties can be explained by the seed dispersal limitation illustrated above (as inferred by geographical separation) and by environmental heterogeneity (as inferred by precipitation or elevation) or by a combination of both. After all, the geological changes, drainage reorganization, and floristic differences following the Himalayan uplift have been suggested to affect the genetic structure of S. davidii. These results provide new insights into the phylogeographic pattern of plants in China. In addition, the unique population genetic structure found in S. davidii has provided important insights into the evolutionary history of this species. The genetic profile uncovered in this study is also critical for its conservation management. Our study has uncovered the existence of at least two ‘evolutionary significant units’ independent units within S. davidii, corresponding to var. davidii from eastern region and var. chuansinensis from western region. The conservation efforts should first focus on most western populations and on the southeastern ones exhibiting high levels of genetic diversity, while the genetically homogeneous northeastern populations located in the degraded Loess Plateau should require much greater conservation 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investigating sympatric distribution of Rhododendron irroratum, examing the variation of floral characters and sequencing the ITS and other chloroplast segements, we find that (1) R. irroratum might be of hybrid origin, with its maternal parent R. delavayi or R. decorum. (2) The ancestral haplotype of R. irroratum might be identical to that of R. decorum, and it is under ongoing introgression from R. delavayi. 1. The natural distribution, Seven distribution sites of R. irroratum in Guizhou and Yunnan province were investigated. The result shows that R. irroratum is sympatric with R. delavayi, R. decorum and R. agastum. R. delavayi is widespread across the above-mentioned seven sites, whereas R. agastum is scarce in DaPingDi, HuaDianBa and HeQing sites. R. irroratum and R. agastum distribute at the higher elevation compared to that of R. decorum, while R. delavayi is of widespread distribution across both regions of R. decorum and R. irroratum.2. Floral variation of R. irroratum among populations, The floral characters remain vary within and among populations except for the stamen number and the petal number. Seven floral characters correlates with each other among populations, of 28 different combinations, 26 reveal significant correlation, and 23 extremely significant correlation. The PCA analysis shows that the first two components account for 52.18% of the total variation. The dendrogram tree is divided into four main parts, roughly representing the respective populations, which is constructed using 22 R. irroratum individuals. 3. Putative Development and the transferability test of SSR makers, Fifteen microsatellite loci were developed and characterized in R. delavayi. The average allele number of these microsatellites was 4 per locus, ranging from 3 to 6. The ranges of expected (HE) and observed (HO) heterozygosities were 0.0365-0.7091 and 0.0263-0.9512, respectively. Seven loci (R-111, R-112, R-147, R-299, R-320, R-335, and R-544) deviated significantly from the HWE (P﹤0.01). No significant linkage disequilibrium was detected between locus pairs except for three locus pairs: R-299 and R-544, R-166 and R-320, R-111 and R-320. Cross-species amplification in R. agastum, R. decorum, and R. irroratum showed that a subset of these markers holds promise for congeneric species study.4. ITS, matK, trnH-psbA and rbcL sequences. R. delavayi has six sites different from that of R. decorum in its ITS region, whereas R. agastum reveals double peaks at the corresponding sites and R. irroratum is identical to that of R. delavayi. The chloroplast segements show that some R. irroratum individuals share the same haplotype with R. delavayi and others share them with R. decorum.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=Cytology&&fq=dc.project.title_filter%3AThrough%5C+investigating%5C+sympatric%5C+distribution%5C+of%5C+Rhododendron%5C+irroratum%2C%5C+examing%5C+the%5C+variation%5C+of%5C+floral%5C+characters%5C+and%5C+sequencing%5C+the%5C+ITS%5C+and%5C+other%5C+chloroplast%5C+segements%2C%5C+we%5C+find%5C+that%5C+%5C%281%5C%29%5C+R.%5C+irroratum%5C+might%5C+be%5C+of%5C+hybrid%5C+origin%2C%5C+with%5C+its%5C+maternal%5C+parent%5C+R.%5C+delavayi%5C+or%5C+R.%5C+decorum.%5C+%5C%282%5C%29%5C+The%5C+ancestral%5C+haplotype%5C+of%5C+R.%5C+irroratum%5C+might%5C+be%5C+identical%5C+to%5C+that%5C+of%5C+R.%5C+decorum%2C%5C+and%5C+it%5C+is%5C+under%5C+ongoing%5C+introgression%5C+from%5C+R.%5C+delavayi.%5C+1.%5C+The%5C+natural%5C+distribution%2C%5C+Seven%5C+distribution%5C+sites%5C+of%5C+R.%5C+irroratum%5C+in%5C+Guizhou%5C+and%5C+Yunnan%5C+province%5C+were%5C+investigated.%5C+The%5C+result%5C+shows%5C+that%5C+R.%5C+irroratum%5C+is%5C+sympatric%5C+with%5C+R.%5C+delavayi%2C%5C+R.%5C+decorum%5C+and%5C+R.%5C+agastum.%5C+R.%5C+delavayi%5C+is%5C+widespread%5C+across%5C+the%5C+above%5C-mentioned%5C+seven%5C+sites%2C%5C+whereas%5C+R.%5C+agastum%5C+is%5C+scarce%5C+in%5C+DaPingDi%2C%5C+HuaDianBa%5C+and%5C+HeQing%5C+sites.%5C+R.%5C+irroratum%5C+and%5C+R.%5C+agastum%5C+distribute%5C+at%5C+the%5C+higher%5C+elevation%5C+compared%5C+to%5C+that%5C+of%5C+R.%5C+decorum%2C%5C+while%5C+R.%5C+delavayi%5C+is%5C+of%5C+widespread%5C+distribution%5C+across%5C+both%5C+regions%5C+of%5C+R.%5C+decorum%5C+and%5C+R.%5C+irroratum.2.%5C+Floral%5C+variation%5C+of%5C+R.%5C+irroratum%5C+among%5C+populations%2C%5C+The%5C+floral%5C+characters%5C+remain%5C+vary%5C+within%5C+and%5C+among%5C+populations%5C+except%5C+for%5C+the%5C+stamen%5C+number%5C+and%5C+the%5C+petal%5C+number.%5C+Seven%5C+floral%5C+characters%5C+correlates%5C+with%5C+each%5C+other%5C+among%5C+populations%2C%5C+of%5C+28%5C+different%5C+combinations%2C%5C+26%5C+reveal%5C+significant%5C+correlation%2C%5C+and%5C+23%5C+extremely%5C+significant%5C+correlation.%5C+The%5C+PCA%5C+analysis%5C+shows%5C+that%5C+the%5C+first%5C+two%5C+components%5C+account%5C+for%5C+52.18%25%5C+of%5C+the%5C+total%5C+variation.%5C+The%5C+dendrogram%5C+tree%5C+is%5C+divided%5C+into%5C+four%5C+main%5C+parts%2C%5C+roughly%5C+representing%5C+the%5C+respective%5C+populations%2C%5C+which%5C+is%5C+constructed%5C+using%5C+22%5C+R.%5C+irroratum%5C+individuals.%5C+3.%5C+Putative%5C+Development%5C+and%5C+the%5C+transferability%5C+test%5C+of%5C+SSR%5C+makers%2C%5C+Fifteen%5C+microsatellite%5C+loci%5C+were%5C+developed%5C+and%5C+characterized%5C+in%5C+R.%5C+delavayi.%5C+The%5C+average%5C+allele%5C+number%5C+of%5C+these%5C+microsatellites%5C+was%5C+4%5C+per%5C+locus%2C%5C+ranging%5C+from%5C+3%5C+to%5C+6.%5C+The%5C+ranges%5C+of%5C+expected%5C+%5C%28HE%5C%29%5C+and%5C+observed%5C+%5C%28HO%5C%29%5C+heterozygosities%5C+were%5C+0.0365%5C-0.7091%5C+and%5C+0.0263%5C-0.9512%2C%5C+respectively.%5C+Seven%5C+loci%5C+%5C%28R%5C-111%2C%5C+R%5C-112%2C%5C+R%5C-147%2C%5C+R%5C-299%2C%5C+R%5C-320%2C%5C+R%5C-335%2C%5C+and%5C+R%5C-544%5C%29%5C+deviated%5C+significantly%5C+from%5C+the%5C+HWE%5C+%5C%28P%EF%B9%A40.01%5C%29.%5C+No%5C+significant%5C+linkage%5C+disequilibrium%5C+was%5C+detected%5C+between%5C+locus%5C+pairs%5C+except%5C+for%5C+three%5C+locus%5C+pairs%5C%3A%5C+R%5C-299%5C+and%5C+R%5C-544%2C%5C+R%5C-166%5C+and%5C+R%5C-320%2C%5C+R%5C-111%5C+and%5C+R%5C-320.%5C+Cross%5C-species%5C+amplification%5C+in%5C+R.%5C+agastum%2C%5C+R.%5C+decorum%2C%5C+and%5C+R.%5C+irroratum%5C+showed%5C+that%5C+a%5C+subset%5C+of%5C+these%5C+markers%5C+holds%5C+promise%5C+for%5C+congeneric%5C+species%5C+study.4.%5C+ITS%2C%5C+matK%2C%5C+trnH%5C-psbA%5C+and%5C+rbcL%5C+sequences.%5C+R.%5C+delavayi%5C+has%5C+six%5C+sites%5C+different%5C+from%5C+that%5C+of%5C+R.%5C+decorum%5C+in%5C+its%5C+ITS%5C+region%2C%5C+whereas%5C+R.%5C+agastum%5C+reveals%5C+double%5C+peaks%5C+at%5C+the%5C+corresponding%5C+sites%5C+and%5C+R.%5C+irroratum%5C+is%5C+identical%5C+to%5C+that%5C+of%5C+R.%5C+delavayi.%5C+The%5C+chloroplast%5C+segements%5C+show%5C+that%5C+some%5C+R.%5C+irroratum%5C+individuals%5C+share%5C+the%5C+same%5C+haplotype%5C+with%5C+R.%5C+delavayi%5C+and%5C+others%5C+share%5C+them%5C+with%5C+R.%5C+decorum."},{"jsname":"Trigonobalanus doichangensis is an endangered plant. In this paper, the megasporogenesis and development of female gametophyte, seed morphological traits and seed germination, seed conservation, micropropagation and acclimatization of this species were studied. Combined with the published results of cytology, molecular genetics and other researches,the mechanisms of extinction, basic biology and technology of germplasm conservation and acclimatization of T. doichangensis were discussed. The main results are summarized as follows:1. Megasporogenesis and development of female gametophyte，Stamens exist under the stigma of T. doichangensis, and the pollen is aborted on the later development stage of pistil, therefore, the pistillate flower in function is hermaphrodite flower in morphology. The ovule is anatropous, bitegmic and crassinucellate. The primary archesporium is hypodermal and single-celled and the sporogenous cell of the nucellus functions directly as a megaspore mother cell which goes meiosis to form a linear tetrad. The chalazal megaspore of the tetrad is functional. The development of embryo sac conforms to the polygonum type. There are six ovules in the ovary of T. doichangensis, and only one develops into a seed in normal fruits. In the process of megasporogenesis and development of female gametophyte, there are several links of abortion, and 93.3% of mature embryo sacs is aborted.2. Morphological characters and germination of seeds，Most of the variation occurred among individual trees within populations in seed morphological traits (length, width and 1000-seed weight) and germination-related indices (germination percentage, germination index and vigor index). In addition, the variation in percentage of well-developed seeds among populations and among individual trees within populations is equal, each accounting for 48%. Each of seed morphological traits has significantly positive correlation with each other (p < 0.01), but they have no significant correlation with percentage of well-developed seeds and germination-related indices. In the same batch of seeds of T. doichangensis, there are light-colored and dark-colored seed coats, and development of light-colored seeds is significantly poorer than that of dark-colored seeds.The sensitivity of seeds to high temperature varys in different stages of seed imbibition. In each stage, heat acclimatization don’t increase germination percentage, germination index and fresh weight of seedlings. If the distilled water is substituted by solution of SA during seed imbibition, seed germination and germination index after heat shock are not significantly different from control, but they are significantly higher than that of other treatments. Moreover, when the seeds are treatmented with SA, the fresh weight of seedlings is significantly higher than that of control and other treatments.3. Seed conservation，Seeds of T. doichangensis belong to orthodox seeds which can tolerate certain level of dehydration. The condition of low temperature and low water content of seeds is conducive to seed conservation.Germination of fresh seeds shows significant variation among populations, howerer, germination of the seeds after storage for one year in room temperature shows no significant variation among populations.High temperature and high relative humidity damages the seeds more severely than high temperature does. In addition, low water content of seeds enable the seeds to be more tolerant to high temperature.The electrical conductivity, dehydrogenase activity and germination percentage have no significant correlation with each other.4. Micropropagation and in vitro conservation，Cotyledonary nodes are a kind of efficient explants. Low salt media are conducive to shoot propagation and root induction.The maximum multiplication rate (20-25 shoots/explant within 4 months) is achieved on quarter-strength Murashige and Skoog (1/4 MS) medium supplemented with 1 mg·L-1 6-benzyladenine (6-BA) and 0.05 mg·L-1 α-naphthaleneacetic acid (NAA).Rooting is promoted by auxins, however, IBA alone or low concentrations of NAA are preferable due to small amount of callus induced. The research has established an efficient protocol for micropropagation of T. doichangensis, and it provides technology support for in vitro conservation of special germplasm of the species.5. Acclimatization，Quercus variabilis, Cyclobalanopsis glaucoides and T. doichangensis belong to the family of Fagaceae, and the natural distribution ranges of the 3 species are decreasing in turn. The research suggests that the ranges of temperature tolerance of the 3 species are decreasing corresponding to their distribution ranges.The high and low semi-lethal temperature of one-year old T. doichangensis is 49.5℃ and -5℃ respectively. It suggests that T. doichangensis has a wide range of basic temperature tolerance. Short-term heat and cold acclimatization cannot expand the range of temperature tolerance. It can be inferred that T. doichangensis may lack induced tolerance to temperature. Under proper conditions, ABA can increase the cold tolerance, and SA can increase the heat tolerance of leaf discs of T. doichangensis.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=Cytology&&fq=dc.project.title_filter%3ATrigonobalanus%5C+doichangensis%5C+is%5C+an%5C+endangered%5C+plant.%5C+In%5C+this%5C+paper%2C%5C+the%5C+megasporogenesis%5C+and%5C+development%5C+of%5C+female%5C+gametophyte%2C%5C+seed%5C+morphological%5C+traits%5C+and%5C+seed%5C+germination%2C%5C+seed%5C+conservation%2C%5C+micropropagation%5C+and%5C+acclimatization%5C+of%5C+this%5C+species%5C+were%5C+studied.%5C+Combined%5C+with%5C+the%5C+published%5C+results%5C+of%5C+cytology%2C%5C+molecular%5C+genetics%5C+and%5C+other%5C+researches%2Cthe%5C+mechanisms%5C+of%5C+extinction%2C%5C+basic%5C+biology%5C+and%5C+technology%5C+of%5C+germplasm%5C+conservation%5C+and%5C+acclimatization%5C+of%5C+T.%5C+doichangensis%5C+were%5C+discussed.%5C+The%5C+main%5C+results%5C+are%5C+summarized%5C+as%5C+follows%5C%3A1.%5C+Megasporogenesis%5C+and%5C+development%5C+of%5C+female%5C+gametophyte%EF%BC%8CStamens%5C+exist%5C+under%5C+the%5C+stigma%5C+of%5C+T.%5C+doichangensis%2C%5C+and%5C+the%5C+pollen%5C+is%5C+aborted%5C+on%5C+the%5C+later%5C+development%5C+stage%5C+of%5C+pistil%2C%5C+therefore%2C%5C+the%5C+pistillate%5C+flower%5C+in%5C+function%5C+is%5C+hermaphrodite%5C+flower%5C+in%5C+morphology.%5C+The%5C+ovule%5C+is%5C+anatropous%2C%5C+bitegmic%5C+and%5C+crassinucellate.%5C+The%5C+primary%5C+archesporium%5C+is%5C+hypodermal%5C+and%5C+single%5C-celled%5C+and%5C+the%5C+sporogenous%5C+cell%5C+of%5C+the%5C+nucellus%5C+functions%5C+directly%5C+as%5C+a%5C+megaspore%5C+mother%5C+cell%5C+which%5C+goes%5C+meiosis%5C+to%5C+form%5C+a%5C+linear%5C+tetrad.%5C+The%5C+chalazal%5C+megaspore%5C+of%5C+the%5C+tetrad%5C+is%5C+functional.%5C+The%5C+development%5C+of%5C+embryo%5C+sac%5C+conforms%5C+to%5C+the%5C+polygonum%5C+type.%5C+There%5C+are%5C+six%5C+ovules%5C+in%5C+the%5C+ovary%5C+of%5C+T.%5C+doichangensis%2C%5C+and%5C+only%5C+one%5C+develops%5C+into%5C+a%5C+seed%5C+in%5C+normal%5C+fruits.%5C+In%5C+the%5C+process%5C+of%5C+megasporogenesis%5C+and%5C+development%5C+of%5C+female%5C+gametophyte%2C%5C+there%5C+are%5C+several%5C+links%5C+of%5C+abortion%2C%5C+and%5C+93.3%25%5C+of%5C+mature%5C+embryo%5C+sacs%5C+is%5C+aborted.2.%5C+Morphological%5C+characters%5C+and%5C+germination%5C+of%5C+seeds%EF%BC%8CMost%5C+of%5C+the%5C+variation%5C+occurred%5C+among%5C+individual%5C+trees%5C+within%5C+populations%5C+in%5C+seed%5C+morphological%5C+traits%5C+%5C%28length%2C%5C+width%5C+and%5C+1000%5C-seed%5C+weight%5C%29%5C+and%5C+germination%5C-related%5C+indices%5C+%5C%28germination%5C+percentage%2C%5C+germination%5C+index%5C+and%5C+vigor%5C+index%5C%29.%5C+In%5C+addition%2C%5C+the%5C+variation%5C+in%5C+percentage%5C+of%5C+well%5C-developed%5C+seeds%5C+among%5C+populations%5C+and%5C+among%5C+individual%5C+trees%5C+within%5C+populations%5C+is%5C+equal%2C%5C+each%5C+accounting%5C+for%5C+48%25.%5C+Each%5C+of%5C+seed%5C+morphological%5C+traits%5C+has%5C+significantly%5C+positive%5C+correlation%5C+with%5C+each%5C+other%5C+%5C%28p%5C+%3C%5C+0.01%5C%29%2C%5C+but%5C+they%5C+have%5C+no%5C+significant%5C+correlation%5C+with%5C+percentage%5C+of%5C+well%5C-developed%5C+seeds%5C+and%5C+germination%5C-related%5C+indices.%5C+In%5C+the%5C+same%5C+batch%5C+of%5C+seeds%5C+of%5C+T.%5C+doichangensis%2C%5C+there%5C+are%5C+light%5C-colored%5C+and%5C+dark%5C-colored%5C+seed%5C+coats%2C%5C+and%5C+development%5C+of%5C+light%5C-colored%5C+seeds%5C+is%5C+significantly%5C+poorer%5C+than%5C+that%5C+of%5C+dark%5C-colored%5C+seeds.The%5C+sensitivity%5C+of%5C+seeds%5C+to%5C+high%5C+temperature%5C+varys%5C+in%5C+different%5C+stages%5C+of%5C+seed%5C+imbibition.%5C+In%5C+each%5C+stage%2C%5C+heat%5C+acclimatization%5C+don%E2%80%99t%5C+increase%5C+germination%5C+percentage%2C%5C+germination%5C+index%5C+and%5C+fresh%5C+weight%5C+of%5C+seedlings.%5C+If%5C+the%5C+distilled%5C+water%5C+is%5C+substituted%5C+by%5C+solution%5C+of%5C+SA%5C+during%5C+seed%5C+imbibition%2C%5C+seed%5C+germination%5C+and%5C+germination%5C+index%5C+after%5C+heat%5C+shock%5C+are%5C+not%5C+significantly%5C+different%5C+from%5C+control%2C%5C+but%5C+they%5C+are%5C+significantly%5C+higher%5C+than%5C+that%5C+of%5C+other%5C+treatments.%5C+Moreover%2C%5C+when%5C+the%5C+seeds%5C+are%5C+treatmented%5C+with%5C+SA%2C%5C+the%5C+fresh%5C+weight%5C+of%5C+seedlings%5C+is%5C+significantly%5C+higher%5C+than%5C+that%5C+of%5C+control%5C+and%5C+other%5C+treatments.3.%5C+Seed%5C+conservation%EF%BC%8CSeeds%5C+of%5C+T.%5C+doichangensis%5C+belong%5C+to%5C+orthodox%5C+seeds%5C+which%5C+can%5C+tolerate%5C+certain%5C+level%5C+of%5C+dehydration.%5C+The%5C+condition%5C+of%5C+low%5C+temperature%5C+and%5C+low%5C+water%5C+content%5C+of%5C+seeds%5C+is%5C+conducive%5C+to%5C+seed%5C+conservation.Germination%5C+of%5C+fresh%5C+seeds%5C+shows%5C+significant%5C+variation%5C+among%5C+populations%2C%5C+howerer%2C%5C+germination%5C+of%5C+the%5C+seeds%5C+after%5C+storage%5C+for%5C+one%5C+year%5C+in%5C+room%5C+temperature%5C+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pingbianensis J. L. Huang & X. Z. Liu, is a newly described perennial herb narrowly distributed in South-east Yunnan, China. It belongs to genera Tupistra Ker Gawler(Liliaceae). It usually occurs on outcrops of bare rock, or occasionally as an epiphyte on tree trunks covered with humus and moss. T. pingbianensis is unusual in that it exhibits rarity according to three different ways of measuring rarity, i.e. it has a small geographical range, is a habitat specialist, and always has low abundance where it occurs. Because of this, T. pingbianensis has been listed as an endangered species and catalogued in the Chinese Species Red List. In order to discuss the causes of rarity of T. pingbianensis, the multidisciplinary investigations of the seed and seedling establishment, cytology, breeding system, and population genetic structure of the endangered T. pingbianensis were performed in this thesis. Besides, the corresponding conservation strategies were also proposed according to the above-mentioned. The main results are summarized as follows:1. Biological traits of T. pingbianensis,T. pingbianensis is a perennial herbaceous with a creeping rhizome, thick basal leaves, and an inflorescence that is a terminal spike. Florescence is from November to December, while fruiting occurs between November and December in the next year. Reproduction and spread also occurs clonally via rhizomes, most seeds simply fall from the mother plant and germinate where they land. It occurs on outcrops of bare rock, or occasionally as an epiphyte on tree trunks covered with humus and moss, which are naturally rare habitat. Throughout its small geographical range, T. pingbianensis occurs as discrete, small populations size. 2. Seed germination traits of T. pingbianensis,Seed morphology was observed and effects of substrates soil types, light, sowing depth on germination percentage of the species T. pingbianensis were investigated primarily. The results showed that the average seed size was (1.17±0.02) cm × (0.79±0.01) cm × (0.77±0.01) cm (length × width × thickness), per-hundred-seed-weight was about 35.03±0.12g. Among the three different substrates soil types and sowing depths, seeds of T. pingbianensis germinate best in alkalescence soil and shallow sowing depth (2cm). It could germinate in the both light and dark, but the germination rate can be accelerated by light obviously. Its seed has high germination rate not just in greenhouse, but also in the field. We considered that this is a good strategy to expand its population in the special habit.3. Karyotype evolution status of T. pingbianensis,The karyotype of total eight species in Campylandra, Tupistra and Aspidistra from China were reported. Considering Tupistra has the similar morphological character with Campylandra but resemble Aspidistra in karyotype. The results support the earlier study that Tupistra is a transition between Compylandra and Aspidistra. Besides, our results also showes that the T. pingbianensis and T. fungilliformis has higher karyotype asymmetry than other species in this genera, which means these species have higher karyotype evolution status. 4. Reproduction ecology of T. pingbianensis, The flower phenology, pollinators of T. pingbianensis were documented herein. We also examined the breeding system of T. pingbianensis and seed fitness traits to determine what forms of pollination and mating occur in this naturally rare species, and is there evidence of inbreeding depression in its populations. The results shows that the flowers opened 10-15 days, which suggest stigma and pollen can keep high vitality for a long time (10-15 days). The only pollinators observed on T. pingbianensis flowers were ants (Aphaenogaster smythiesii Forel,Formicidea), springtail (Hypogastrura sp., Hypogastruridae, Collembola) and one species of beetles (Anomala corpulenta Motsch, Rutelidae). These pollinators generally have restricted movement capacities and hence promote geitonogamy or mating between individuals in close proximity within populations. The results of out crossing index (OCI) pollination experiments in our study suggest that T. pingbianensis has an animal-pollinated, mixed selfing and outcrossing breeding systems. However, a pollination experiment also fail to detect significant inbreeding depression upon F1 fruit set, seed weight and germinate rate fitness-traits. Since naturally rare species T. pingbianensis is not seriously genetically impoverished and likely to have adapted to tolerating a high level of inbreeding early in its history. 5. Conservation genetic of T. pingbianensis, The levels and partitioning of genetic diversity were investigated in Tupistra pingbianensis. Here genetic diversity and patterns of genetic variation within and among 11 populations were analyzed using AFLP markers with 97 individuals across its whole geographical range. High levels of genetic variation were revealed both at the species level (P99 = 96.012%; Ht = 0.302) and at the population level (P99 = 51.41%; Hs = 0.224). Strong genetic differentiation among populations was also detected (FST = 0.2961; ⍬Ⅱ= 0.281), which corresponded to results reported for typical animal-pollinated, mixed selfing and outcrossing plant species. Special habitat and its life history traits may play an important role in shaping the genetic diversity and the genetic structure of this species. Based on the special habitat in T. pingbianensis, the most suitable strategy for its conservation is the protection of its habitat. Moreover, given the observed strong genetic differentiation among populations of T. pingbianensis, the preservation of genetic diversity in this species will require the protection of many populations as possible to maintain the current levels of genetic variability.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=Cytology&&fq=dc.project.title_filter%3ATupistra%5C+pingbianensis%5C+J.%5C+L.%5C+Huang%5C+%5C%26%5C+X.%5C+Z.%5C+Liu%2C%5C+is%5C+a%5C+newly%5C+described%5C+perennial%5C+herb%5C+narrowly%5C+distributed%5C+in%5C+South%5C-east%5C+Yunnan%2C%5C+China.%5C+It%5C+belongs%5C+to%5C+genera%5C+Tupistra%5C+Ker%5C+Gawler%5C%28Liliaceae%5C%29.%5C+It%5C+usually%5C+occurs%5C+on%5C+outcrops%5C+of%5C+bare%5C+rock%2C%5C+or%5C+occasionally%5C+as%5C+an%5C+epiphyte%5C+on%5C+tree%5C+trunks%5C+covered%5C+with%5C+humus%5C+and%5C+moss.%5C+T.%5C+pingbianensis%5C+is%5C+unusual%5C+in%5C+that%5C+it%5C+exhibits%5C+rarity%5C+according%5C+to%5C+three%5C+different%5C+ways%5C+of%5C+measuring%5C+rarity%2C%5C+i.e.%5C+it%5C+has%5C+a%5C+small%5C+geographical%5C+range%2C%5C+is%5C+a%5C+habitat%5C+specialist%2C%5C+and%5C+always%5C+has%5C+low%5C+abundance%5C+where%5C+it%5C+occurs.%5C+Because%5C+of%5C+this%2C%5C+T.%5C+pingbianensis%5C+has%5C+been%5C+listed%5C+as%5C+an%5C+endangered%5C+species%5C+and%5C+catalogued%5C+in%5C+the%5C+Chinese%5C+Species%5C+Red%5C+List.%5C+In%5C+order%5C+to%5C+discuss%5C+the%5C+causes%5C+of%5C+rarity%5C+of%5C+T.%5C+pingbianensis%2C%5C+the%5C+multidisciplinary%5C+investigations%5C+of%5C+the%5C+seed%5C+and%5C+seedling%5C+establishment%2C%5C+cytology%2C%5C+breeding%5C+system%2C%5C+and%5C+population%5C+genetic%5C+structure%5C+of%5C+the%5C+endangered%5C+T.%5C+pingbianensis%5C+were%5C+performed%5C+in%5C+this%5C+thesis.%5C+Besides%2C%5C+the%5C+corresponding%5C+conservation%5C+strategies%5C+were%5C+also%5C+proposed%5C+according%5C+to%5C+the%5C+above%5C-mentioned.%5C+The%5C+main%5C+results%5C+are%5C+summarized%5C+as%5C+follows%5C%3A1.%5C+Biological%5C+traits%5C+of%5C+T.%5C+pingbianensis%2CT.%5C+pingbianensis%5C+is%5C+a%5C+perennial%5C+herbaceous%5C+with%5C+a%5C+creeping%5C+rhizome%2C%5C+thick%5C+basal%5C+leaves%2C%5C+and%5C+an%5C+inflorescence%5C+that%5C+is%5C+a%5C+terminal%5C+spike.%5C+Florescence%5C+is%5C+from%5C+November%5C+to%5C+December%2C%5C+while%5C+fruiting%5C+occurs%5C+between%5C+November%5C+and%5C+December%5C+in%5C+the%5C+next%5C+year.%5C+Reproduction%5C+and%5C+spread%5C+also%5C+occurs%5C+clonally%5C+via%5C+rhizomes%2C%5C+most%5C+seeds%5C+simply%5C+fall%5C+from%5C+the%5C+mother%5C+plant%5C+and%5C+germinate%5C+where%5C+they%5C+land.%5C+It%5C+occurs%5C+on%5C+outcrops%5C+of%5C+bare%5C+rock%2C%5C+or%5C+occasionally%5C+as%5C+an%5C+epiphyte%5C+on%5C+tree%5C+trunks%5C+covered%5C+with%5C+humus%5C+and%5C+moss%2C%5C+which%5C+are%5C+naturally%5C+rare%5C+habitat.%5C+Throughout%5C+its%5C+small%5C+geographical%5C+range%2C%5C+T.%5C+pingbianensis%5C+occurs%5C+as%5C+discrete%2C%5C+small%5C+populations%5C+size.%5C+2.%5C+Seed%5C+germination%5C+traits%5C+of%5C+T.%5C+pingbianensis%2CSeed%5C+morphology%5C+was%5C+observed%5C+and%5C+effects%5C+of%5C+substrates%5C+soil%5C+types%2C%5C+light%2C%5C+sowing%5C+depth%5C+on%5C+germination%5C+percentage%5C+of%5C+the%5C+species%5C+T.%5C+pingbianensis%5C+were%5C+investigated%5C+primarily.%5C+The%5C+results%5C+showed%5C+that%5C+the%5C+average%5C+seed%5C+size%5C+was%5C+%5C%281.17%C2%B10.02%5C%29%5C+cm%5C+%C3%97%5C+%5C%280.79%C2%B10.01%5C%29%5C+cm%5C+%C3%97%5C+%5C%280.77%C2%B10.01%5C%29%5C+cm%5C+%5C%28length%5C+%C3%97%5C+width%5C+%C3%97%5C+thickness%5C%29%2C%5C+per%5C-hundred%5C-seed%5C-weight%5C+was%5C+about%5C+35.03%C2%B10.12g.%5C+Among%5C+the%5C+three%5C+different%5C+substrates%5C+soil%5C+types%5C+and%5C+sowing%5C+depths%2C%5C+seeds%5C+of%5C+T.%5C+pingbianensis%5C+germinate%5C+best%5C+in%5C+alkalescence%5C+soil%5C+and%5C+shallow%5C+sowing%5C+depth%5C+%5C%282cm%5C%29.%5C+It%5C+could%5C+germinate%5C+in%5C+the%5C+both%5C+light%5C+and%5C+dark%2C%5C+but%5C+the%5C+germination%5C+rate%5C+can%5C+be%5C+accelerated%5C+by%5C+light%5C+obviously.%5C+Its%5C+seed%5C+has%5C+high%5C+germination%5C+rate%5C+not%5C+just%5C+in%5C+greenhouse%2C%5C+but%5C+also%5C+in%5C+the%5C+field.%5C+We%5C+considered%5C+that%5C+this%5C+is%5C+a%5C+good%5C+strategy%5C+to%5C+expand%5C+its%5C+population%5C+in%5C+the%5C+special%5C+habit.3.%5C+Karyotype%5C+evolution%5C+status%5C+of%5C+T.%5C+pingbianensis%2CThe%5C+karyotype%5C+of%5C+total%5C+eight%5C+species%5C+in%5C+Campylandra%2C%5C+Tupistra%5C+and%5C+Aspidistra%5C+from%5C+China%5C+were%5C+reported.%5C+Considering%5C+Tupistra%5C+has%5C+the%5C+similar%5C+morphological%5C+character%5C+with%5C+Campylandra%5C+but%5C+resemble%5C+Aspidistra%5C+in%5C+karyotype.%5C+The%5C+results%5C+support%5C+the%5C+earlier%5C+study%5C+that%5C+Tupistra%5C+is%5C+a%5C+transition%5C+between%5C+Compylandra%5C+and%5C+Aspidistra.%5C+Besides%2C%5C+our%5C+results%5C+also%5C+showes%5C+that%5C+the%5C+T.%5C+pingbianensis%5C+and%5C+T.%5C+fungilliformis%5C+has%5C+higher%5C+karyotype%5C+asymmetry%5C+than%5C+other%5C+species%5C+in%5C+this%5C+genera%2C%5C+which%5C+means%5C+these%5C+species%5C+have%5C+higher%5C+karyotype%5C+evolution%5C+status.%5C+4.%5C+Reproduction%5C+ecology%5C+o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combination of Rodgersia, Astilboides, Darmera, Oresitrophe, Bergenia, and Mukdenia by Soltis with the name of Darmera group was supported. The key taxonomic traits of leave arrangement and pubescence were not suppoted by molecular result, especially for taxa from Hengduan Mountains and Himalayas. Multiple sampled Rodgersia aesculifolia was not monophyly, samples from Hengduan Mountains (R. henrici = R. aesculifolia var. henrici) were nested with R. pinnata and R. sambucifolia, while samples from southeast Tibet (R. henrici = R. aesculifolia var. henrici) form a clade sister to the former taxa. Samples of R. aesculifolia from Qingling and Daba mountains (R. aesculifolia var. aesculifolia = Triditional R. asculifolia) are distinct with all the above. R. aesculifolia var. henrici is distinct from A. aesculifolia var. aesculifolia and is suggested be raised to spcies level again as Rosgersia henrici Franchet. Populations of R. henrici from western Yunnan are grouping with R. pinnata, natural hybridization are supposed to occur. Rodgersia podophylla from Korea and Japan is sister to Chinese Rodgersia. The furthermore study of infraspecific taxonomy of R. aesculifolia is suggested.The relict Rodgersia nepalensis from eastern Nepal branched first in the combined ITS and plastid tree, which is different from evidences of the traditional morphology and cytology. This might due to its narrow distribution disjuct from other species of Rodgersia, low level of gene flow and subsequent conserved genetic system. It may evolved by polyploidy, the spcecialized morphological character of R. nepalensis may be a strategy for ecological tolerance and self-protection. Our molecular phylogeny of Rodgersia is accordant with the former morphological and cytological evidences. Hybridization and polyploidy may play an important role in evolution and speciation in Rodgersia. Rodgersia may origin from northestern Asia and migrated into Hengduan mountains and Himalayas through Qingling and Daba mountains. Based on present molecular results, as well as original description papers and Type specimen, six species and two variaties were recognized in Rodgersia. Rodgersia henrici was recognized in our study, and was supported to be raised to species level again","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=Cytology&&fq=dc.project.title_filter%3Athe%5C+combination%5C+of%5C+Rodgersia%2C%5C+Astilboides%2C%5C+Darmera%2C%5C+Oresitrophe%2C%5C+Bergenia%2C%5C+and%5C+Mukdenia%5C+by%5C+Soltis%5C+with%5C+the%5C+name%5C+of%5C+Darmera%5C+group%5C+was%5C+supported.%5C+The%5C+key%5C+taxonomic%5C+traits%5C+of%5C+leave%5C+arrangement%5C+and%5C+pubescence%5C+were%5C+not%5C+suppoted%5C+by%5C+molecular%5C+result%2C%5C+especially%5C+for%5C+taxa%5C+from%5C+Hengduan%5C+Mountains%5C+and%5C+Himalayas.%5C+Multiple%5C+sampled%5C+Rodgersia%5C+aesculifolia%5C+was%5C+not%5C+monophyly%2C%5C+samples%5C+from%5C+Hengduan%5C+Mountains%5C+%5C%28R.%5C+henrici%5C+%3D%5C+R.%5C+aesculifolia%5C+var.%5C+henrici%5C%29%5C+were%5C+nested%5C+with%5C+R.%5C+pinnata%5C+and%5C+R.%5C+sambucifolia%2C%5C+while%5C+samples%5C+from%5C+southeast%5C+Tibet%5C+%5C%28R.%5C+henrici%5C+%3D%5C+R.%5C+aesculifolia%5C+var.%5C+henrici%5C%29%5C+form%5C+a%5C+clade%5C+sister%5C+to%5C+the%5C+former%5C+taxa.%5C+Samples%5C+of%5C+R.%5C+aesculifolia%5C+from%5C+Qingling%5C+and%5C+Daba%5C+mountains%5C+%5C%28R.%5C+aesculifolia%5C+var.%5C+aesculifolia%5C+%3D%5C+Triditional%5C+R.%5C+asculifolia%5C%29%5C+are%5C+distinct%5C+with%5C+all%5C+the%5C+above.%5C+R.%5C+aesculifolia%5C+var.%5C+henrici%5C+is%5C+distinct%5C+from%5C+A.%5C+aesculifolia%5C+var.%5C+aesculifolia%5C+and%5C+is%5C+suggested%5C+be%5C+raised%5C+to%5C+spcies%5C+level%5C+again%5C+as%5C+Rosgersia%5C+henrici%5C+Franchet.%5C+Populations%5C+of%5C+R.%5C+henrici%5C+from%5C+western%5C+Yunnan%5C+are%5C+grouping%5C+with%5C+R.%5C+pinnata%2C%5C+natural%5C+hybridization%5C+are%5C+supposed%5C+to%5C+occur.%5C+Rodgersia%5C+podophylla%5C+from%5C+Korea%5C+and%5C+Japan%5C+is%5C+sister%5C+to%5C+Chinese%5C+Rodgersia.%5C+The%5C+furthermore%5C+study%5C+of%5C+infraspecific%5C+taxonomy%5C+of%5C+R.%5C+aesculifolia%5C+is%5C+suggested.The%5C+relict%5C+Rodgersia%5C+nepalensis%5C+from%5C+eastern%5C+Nepal%5C+branched%5C+first%5C+in%5C+the%5C+combined%5C+ITS%5C+and%5C+plastid%5C+tree%2C%5C+which%5C+is%5C+different%5C+from%5C+evidences%5C+of%5C+the%5C+traditional%5C+morphology%5C+and%5C+cytology.%5C+This%5C+might%5C+due%5C+to%5C+its%5C+narrow%5C+distribution%5C+disjuct%5C+from%5C+other%5C+species%5C+of%5C+Rodgersia%2C%5C+low%5C+level%5C+of%5C+gene%5C+flow%5C+and%5C+subsequent%5C+conserved%5C+genetic%5C+system.%5C+It%5C+may%5C+evolved%5C+by%5C+polyploidy%2C%5C+the%5C+spcecialized%5C+morphological%5C+character%5C+of%5C+R.%5C+nepalensis%5C+may%5C+be%5C+a%5C+strategy%5C+for%5C+ecological%5C+tolerance%5C+and%5C+self%5C-protection.%5C+Our%5C+molecular%5C+phylogeny%5C+of%5C+Rodgersia%5C+is%5C+accordant%5C+with%5C+the%5C+former%5C+morphological%5C+and%5C+cytological%5C+evidences.%5C+Hybridization%5C+and%5C+polyploidy%5C+may%5C+play%5C+an%5C+important%5C+role%5C+in%5C+evolution%5C+and%5C+speciation%5C+in%5C+Rodgersia.%5C+Rodgersia%5C+may%5C+origin%5C+from%5C+northestern%5C+Asia%5C+and%5C+migrated%5C+into%5C+Hengduan%5C+mountains%5C+and%5C+Himalayas%5C+through%5C+Qingling%5C+and%5C+Daba%5C+mountains.%5C+Based%5C+on%5C+present%5C+molecular%5C+results%2C%5C+as%5C+well%5C+as%5C+original%5C+description%5C+papers%5C+and%5C+Type%5C+specimen%2C%5C+six%5C+species%5C+and%5C+two%5C+variaties%5C+were%5C+recognized%5C+in%5C+Rodgersia.%5C+Rodgersia%5C+henrici%5C+was%5C+recognized%5C+in%5C+our%5C+study%2C%5C+and%5C+was%5C+supported%5C+to%5C+be%5C+raised%5C+to%5C+species%5C+level%5C+again"},{"jsname":"lastIndexed","jscount":"2024-08-30"}],"资助项目","dc.project.title_filter")'>
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