Sino-Japanese Floristic Region Research Articles

Intraspecific phylogeny and genomic resources development for an important medical plant Dioscorea nipponica, based on low-coverage whole genome sequencing data.

Dioscorea nipponica Makino, a perennial twining herb with medicinal importance, has a disjunctive distribution in the Sino-Japanese Floristic Region. It has a long history in traditional Chinese medicine, with demonstrated efficacy against various health conditions. However, the limited genomic data and knowledge of genetic variation have hindered its comprehensive exploration, utilization and conservation. In this study, we undertook low-coverage whole genome sequencing of diverse D. nipponica accessions to develop both plastome (including whole plastome sequences, plastome-derived SSRs and plastome-divergent hotspots) and nuclear genomic resources (including polymorphic nuclear SSRs and single-copy nuclear genes), as well as elucidate the intraspecific phylogeny of this species. Our research revealed 639 plastome-derived SSRs and highlighted six key mutational hotspots (namely CDS ycf1, IGS trnL-rpl32, IGS trnE-trnT, IGS rps16-trnQ, Intron 1 of clpP, and Intron trnG) within these accessions. Besides, three IGS regions (i.e., ndhD-cssA, trnL-rpl32, trnD-trnY), and the intron rps16 were identified as potential markers for distinguishing D. nipponica from its closely related species. In parallel, we successfully developed 988 high-quality candidate polymorphic nuclear SSRs and identified 17 single-copy nuclear genes for D. nipponica, all of which empower us to conduct in-depth investigations into phylogenetics and population genetics of this species. Although our phylogenetic analyses, based on plastome sequences and single-copy nuclear genes revealed cytonuclear discordance within D. nipponica, both findings challenged the current subspecies classification. In summary, this study developed a wealth of genomic resources for D. nipponica and enhanced our understanding of the intraspecific phylogeny of this species, offering valuable insights that can be instrumental in the conservation and strategic utilization of this economically significant plant.

DNA barcoding, phylogeny and phylogeography of the cyst nematode species of the Schachtii group from the genus Heterodera (Tylenchida: Heteroderidae)

Summary Cyst-forming nematodes of the genus Heterodera are highly derived and economically important plant parasites. The Schachtii group of this genus is one of the largest ones with a total of 18 species parasitising dicotyledons. In this study, we provided comprehensive phylogenetic analyses of several hundred COI and ITS rRNA gene sequences of selected species from the Schachtii group, including H. betae, H. cajani, H. ciceri, H. galeopsidis, H. glycines, H. medicaginis, H. mediterranea, H. schachtii, H. sonchophila and H. trifolii, using Bayesian inference, maximum likelihood, and statistical parsimony. One hundred and twenty four new COI, 57 ITS rRNA and eight hsp90 gene sequences from 81 nematode populations collected in 19 countries were obtained in this study. Our study showed that the ITS rRNA gene has limited discrimination power compared to the COI gene. However, our analysis also revealed that partial COI gene sequences were identical for H. trifolii, H. betae and H. galeopsidis. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it was hypothesised that the majority of the Schachtii group species originated and diversified in the Mediterranean Basin biodiversity hotspot during the Pleistocene and then dispersed from this region across the world. The Sino-Japanese Floristic Region is likely one of the centres of diversification for the soybean cyst nematode, which showed distinct population structure. The possible role of hybridisation and polyploidisation in the evolution of species of the Schachtii group is discussed.

Did Late Quaternary climate change trigger shifts in mating system in temperate plant species of the Sino-Japanese Floristic Region? A commentary on 'Genetic and demographic signatures accompanying the evolution of the selfing syndrome in Daphne kiusiana, an evergreen shrub'.

Did Late Quaternary climate change trigger shifts in mating system in temperate plant species of the Sino-Japanese Floristic Region? A commentary on 'Genetic and demographic signatures accompanying the evolution of the selfing syndrome in Daphne kiusiana, an evergreen shrub'.

Pre-quaternary diversification and glacial demographic expansions of Cardiocrinum (Liliaceae) in temperate forest biomes of Sino-Japanese Floristic Region

The Sino-Japanese Floristic Region (SJFR) in East Asia is one of the most diverse temperate floras in the world. However, the relative influence of Neogene palaeogeographical changes and Quaternary climatic fluctuations as causal mechanisms on species diversification remains largely controversial, because most divergence time estimates were inferred from single-locus data and have limited geographic or taxonomic sampling. To evaluate these influences, we use SNP markers from restriction site-associated DNA sequencing (RAD-Seq) loci and expressed sequence tags-simple sequence repeat (EST-SSR) markers to investigate the levels of genetic variation, speciation and demographic history of the temperate-deciduous forest (TDF) endemic Cardiocrinum (Endlicher) Lindley (Liliaceae), a genus comprising three species in China (C. giganteum, C. cathayanum) and Japan (C. cordatum). Phylogenomic and population genomic coalescent-based analyses demonstrated that Late Neogene tectonic/climatic events triggered speciation of Cardiocrinum, and Pleistocene climatic fluctuations had limited influence on its divergence history. Population demographic inference using Approximate Bayesian Computation from EST-SSRs and palaeoclimatic niche models both indicated that all three Cardiocrinum species experienced population expansions during the transition from the LIG to the LGM. We also discussed the implications of these results on the conservation of montane TDF species in the SJFR under ongoing environmental change. Our results improve our understanding of how the constituents of montane TDF across the SJFR responded to previous periods of rapid climate and environmental change in terms of speciation and population demographic processes.

Phylogeographic Analysis and Genetic Structure of an Endemic Sino-Japanese Disjunctive Genus Diabelia (Caprifoliaceae).

The Sino-Japanese Floristic Region (SJFR) is a key area for plant phylogeographical research, due to its very high species diversity and disjunct distributions of a large number of species and genera. At present, the root cause and temporal origin of the discontinuous distribution of many plants in the Sino-Japanese flora are still unclear. Diabelia (Caprifoliaceae; Linnaeoideae) is a genus endemic to Asia, mostly in Japan, but two recent discoveries in China raised questions over the role of the East China Sea (ECS) in these species' disjunctions. Chloroplast DNA sequence data were generated from 402 population samples for two regions (rpl32-trnL, and trnH-psbA) and 11 nuclear microsatellite loci were screened for 549 individuals. Haplotype, population-level structure, combined analyses of ecological niche modeling, and reconstruction of ancestral state in phylogenies were also performed. During the Last Glacial Maximum (LGM) period after the Tertiary, Diabelia was potentially widely distributed in southeastern China, the continental shelf of the East China Sea and Japan (excluding Hokkaido). After LGM, all populations in China have disappeared except those in Zhejiang which may represent a Glacial refuge. Populations of Diabelia in Japan have not experienced significant bottleneck effects, and populations have maintained a relatively stable state. The observed discontinuous distribution of Diabelia species between China and Japan are interpreted as the result of relatively ancient divergence. The phylogenetic tree of chloroplast fragments shows the characteristics of multi-origin evolution (except for D. sanguinea). STRUCTURE analysis of nuclear Simple Sequence Repeat (nSSR) showed that the plants of the Diabelia were divided into five gene pools: D. serrata, D. spathulata, D. sanguinea, D. ionostachya (D. spathulata var. spathulata-Korea), and populations of D. ionostachya var. ionostachya in Yamagata prefecture, northern Japan. Molecular evidence provides new insights of Diabelia into biogeography, a potential glacial refuge, and population-level genetic structure within species. In the process of species differentiation, ECS acts as a corridor for two-way migration of animals and plants between China and Japan during glacial maxima, providing the possibility of secondary contact for discontinuously distributed species between China and Japan, or as a filter (creating isolation) during glacial minima. The influence of the ECS in speciation and biogeography of Diabelia in the Tertiary remains unresolved in this study. Understanding origins, evolutionary histories, and speciation will provide a framework for the conservation and cultivation of Diabelia.

Species delimitation in the East Asian species of the relict tree genus Zelkova (Ulmaceae): A complex history of diversification and admixture among species

Zelkova species, trees of the elm family (Ulmaceae), are part of the Cenozoic relict flora. In western Eurasia, the genus comprises three species that are restricted to disjunct areas (Z. sicula on Sicily, Z. abelicea on Crete and Z. carpinifolia in Transcaucasia). The situation is different in East Asia, where three species (Z. serrata, Z. schneideriana and Z. sinica) have at least partly overlapping distributions. The phylogenetic and phylogeographic status of these East Asian species is still not well understood, mainly since all previous studies used almost exclusively plant material collected in botanical gardens and were based on very small numbers of individuals. Our study is the first based on 33 natural populations covering all important areas with Zelkova species in the Sino-Japanese Floristic Region. Chloroplast and microsatellite markers were used, and Bayesian analyses were run for both types of markers. East Asian Zelkova species cluster into two groups that partially overlap when comparing the two types of markers. For chloroplast markers, the two groups coincide with all Japanese, some Korean and northern Chinese Z. serrata in one group and all other individuals in the other group, regardless of whether they are attributed to Z. serrata, Z. sinica or Z. schneideriana from Korea, mainland China and Taiwan. At the nuclear level, however, the clustering clearly groups all the Z. serrata individuals together, regardless of whether they are from Japan, Korea or China, and the two other species in a second group. This complex genetic pattern in East Asian Zelkova species is most likely due to a combination of ancient diversification and speciation events and more recent hybridization during the last glacial/interglacial retractions and recolonizations. One of the surprising results of our study concerns the populations from Taiwan, which are genetically similar to Z. schneideriana. Thus, their assignation to a separate taxon (Z. tarokoensis) or to a variety of Z. serrata (Z. serrata var. tarokoensis), as currently reported in all local and national floras, might be in need of revision. Furthermore, our results indicate that the East Asian species are more closely related to Z. carpinifolia than to any other Western European species. Haplotypes of Z. sicula and Z. abelicea (Mediterranean region) as well as those of Z. sinica and Z. schneideriana (East Asia) seem to have diversified more recently. The most ancient haplotypes are found among the western Eurasian Z. carpinifolia and the East Asian Z. serrata. This result is in agreement with the carpinifolia and serrata-like morphotypes commonly found in the fossil record.

Comparative Analysis of the Complete Chloroplast Genome Sequences of Three Closely Related East-Asian Wild Roses (Rosa sect. Synstylae; Rosaceae).

Species belonging to Rosa section Synstylae (Rosaceae) are mainly distributed in East Asia, and represent recently diverged lineages within the genus. Over decades, inferring phylogenetic relationships within section Synstylae have been exceptional challenges, due to short branch lengths and low support values. Of approximately 36 species in the section Synstylae, Rosa multiflora, Rosa luciae and Rosa maximowicziana are widely distributed in the Sino-Japanese floristic region. In this study, we assembled chloroplast genomes of these three species to compare the genomic features within section Synstylae, and to compare with other infrageneric groups. We found that three Rosa sect. Synstylae species had lost infA genes with pseudogenization, and they were almost identical to each other. Two protein-coding gene regions (ndhF and ycf1) and five non-coding regions (5’matK-trnK, psbI-trnS-trnG, rps16-trnG, rpoB-trnC, and rps4-trnT) were identified as being highly informative markers. Within three section Synstylae chloroplast genomes, 85 simple sequence repeat (SSR) motifs were detected, of which at least 13 motifs were identified to be effective markers. The phylogenetic relationships of R. multiflora, R. luciae and R. maximowicziana could not be resolved, even with chloroplast genome-wide data. This study reveals the chloroplast genomic data of Rosa sect. Synstylae, and it provides valuable markers for DNA barcoding and phylogenetic analyses for further studies.

Molecular phylogeny and taxonomic implications of Asarum (Aristolochiaceae) based on ITS and matK sequences

AbstractThe genus Asarum (Aristolochiaceae) encompasses approximately 120 species from five sections. Taxonomic controversies concerning the genus Asarum and/or its intrageneric classification remain unresolved. In particular, sect. Heterotropa accounts for a large percentage of the genus (80 of 120 species) and is well diverged in the Sino–Japanese Forest subkingdom. Reconstruction of Heterotropa phylogeny and estimation of its divergence times would provide significant insight into the process of species diversity in the Sino–Japanese floristic region. This study encompassed 106 operational taxonomic units (OTUs), and phylogenetic analyses were conducted based on internal transcribed spacer (ITS) and matK sequences. Although the matK sequences provided informative results solely for section Geotaenium, phylogenetic trees based on ITS regions yielded a clear result for several sections. Three sections, Asarum, Geotaenium and Asiasarum, were supported as robust monophyletic groups, whereas Heterotropa had low support. Sect. Hexastylis was revealed to be polyphyletic, suggesting taxonomic reconstruction would be needed. Sect. Heterotropa comprises two clades, which correspond to species distribution ranges: mainland China and the island arc from Taiwan to mainland Japan via the Ryukyu Islands. It is notable that the common ancestry of the latter clade in the eastern Asian islands was highly supported, suggesting that the present species diversity of Heterotropa was initially caused by allopatric range fragmentation in East Asia.

Phylogeography of endangered Dendrobium moniliforme in East Asia based on mitochondrial DNA sequence variations

Belonging to the genus Dendrobium of Orchidaceae, Dendrobium moniliforme is an endangered species with disjunct distribution in East Asia, possessing significant medicinal value. To investigate its phylogeography, this study compared sequences of two mitochondrial DNA (mtDNA) fragments (nad 1/b-c and nad 7/2-3) from 143 samples of 18 natural populations of D. moniliforme almost covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. As a result, a total of 30 mtDNA haplotypes were identified in these populations which revealed high levels of haplotype diversity (H d = 0.8733) and total genetic diversity (H T = 0.8886). Additionally, G ST value being significantly lower (0.451) than N ST value (0.722) (P < 0.05) indicated the presence of strong phylogeographic structure in these populations, and the network of mtDNA haplotypes showed that all haplotypes were divided into two clades (A and B). Haplotype overlap was observed among several D. moniliforme population groups in mainland China, suggesting the occurrence of ongoing and/or historical gene flow among them. No common haplotypes were shared by D. moniliforme populations from mainland China and the CKJ Islands (representing Taiwan [China], South Korea, and Japan collectively), pointing to their allopatric evolution in the two regions. Moreover, mismatch distribution analysis and neutral test of mtDNA data rejected the population expansion model. According to the mtDNA-based results, we infer that multiple refugia for D. moniliforme existed in the SJFR of East Asia during the Quaternary glacial period.

Iteration expansion and regional evolution: phylogeography of Dendrobium officinale and four related taxa in southern China

The genus Dendrobium was used as a case study to elucidate the evolutionary history of Orchidaceae in the Sino-Japanese Floristic Region (SJFR) and Southeast Asia region. These evolutionary histories remain largely unknown, including the temporal and spatial distribution of the evolutionary events. The present study used nuclear and plastid DNA to determine the phylogeography of Dendrobium officinale and four closely related taxa. Plastid DNA haplotype and nuclear data were shown to be discordant, suggesting reticulate evolution drove the species’ diversification. Rapid radiation and genetic drift appeared to drive the evolution of D. tosaense and D. flexicaule, whereas introgression or hybridization might have been involved in the evolution of D. scoriarum and D. shixingense. The phylogeographical structure of D. officinale revealed that core natural distribution regions might have served as its glacial refuges. In recent years, human disturbances caused its artificial migration and population extinction. The five taxa may have originated from the Nanling Mountains and the Yungui Plateau and then migrated northward or eastward. After the initial iteration expansion, D. officinale populations appeared to experience the regional evolutionary patterns in different regions and follow the sequential or rapid decline in gene exchange.

Phylogeographic breaks and the mechanisms of their formation in the Sino-Japanese floristic region

Phylogeographic breaks and the mechanisms of their formation in the Sino-Japanese floristic region

Molecular phylogeny, biogeography and ecological niche modelling of Cardiocrinum (Liliaceae): insights into the evolutionary history of endemic genera distributed across the Sino-Japanese floristic region.

The patterns of evolutionary assembly in the Sino-Japanese floristic region (SJFR) remain largely unknown due to a lack of integrative multidimensional studies throughout the region. To address this issue, we elucidated the evolutionary history of Cardiocrinum (Liliaceae), a genus containing four taxa distributed across the SJFR. Fifty-four populations were sampled throughout the geographical range of Cardiocrinum to assess genetic structure, analyse phylogenetic relationships and reconstruct ancestral area based on six chloroplast DNA (cpDNA) fragments and three low copy nuclear genes (LCNG). Ecological niche modelling was used to examine the potential range shifts of Cardiocrinum in response to climatic change. The molecular data showed high genetic similarity in the cpDNA (98·37%) and LCNG (94·53%) sequences. The biogeographical analyses revealed that the ancestor of Cardiocrinum diversified during the late Miocene (approx. 7·32 Mya) in Central China. The ancestor of the C. giganteum lineage dispersed westward to the Himalayas and south-west China with the split between C. giganteum and C. giganteum var. yunnanense occurring around 4·11 Mya consistent with the period of orogeny of the Hengduan Mountains. Some populations of the C. cathayanum lineage dispersed eastward to south Japan via the land bridge approx. 4·97 Mya, providing opportunities for allopatric speciation of C. cordatum The predicted suitable habitats of Cardiocrinum have become smaller and more fragmented since the Last Glacial Maximum. Our study provides evidence of a biogeographical pattern of dispersal from Central China to the Himalayas in the west and Japan in the east for genera distributed across the SJFR, and highlights that the orogeny of the Hengduan Mountains and fluctuations of the sea level of the East China Sea played important roles in promoting species divergence.

Phylogeography of the endangered orchid Dendrobium moniliforme in East Asia inferred from chloroplast DNA sequences

The aim of the current study was to elucidate the phylogeographic history of Dendrobium moniliforme, an endangered orchid species, based on two chloroplast DNA (cpDNA) markers (trnC-petN and trnE-trnT). One hundred and thirty-five samples were collected from 18 natural populations of D. moniliforme covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. A total of 35 distinct cpDNA haplotypes were identified in these populations, of which 23 haplotypes were each present in only one sample and thus restricted to a single population. The significantly larger NST value (0.586) than GST (0.328) (p < 0.05) demonstrated the presence of strong phylogeographic structure. Phylogenetic analyses indicated that all haplotypes were clustered into two lineages. The genetic diversity of D. moniliforme was high at the species level, reflected in its haplotype diversity (Hd=0.8862), nucleotide diversity (Pi=0.00361), total genetic diversity (HT=0.9011), and significant differentiation (ΦST=0.5482). Based on mismatch distribution analysis and neutrality tests, population expansion was evident in all sampled populations and also in all populations sampled in mainland China. Three refuge areas were identified, one each in southwestern China, central-southeastern China, and the CKJ (Taiwan, Japan and Korea) Islands. The results supported the hypothesis that glacial refugia were maintained on different spatial-temporal scales in the SJFR during the last glacial maximum or earlier cold periods, suggesting that Quaternary refugial isolation promoted allopatric speciation of D. moniliforme in East Asia.

Phylogeographical studies of Glycine soja: implicating the refugium during the Quaternary glacial period and large-scale expansion after the Last Glacial Maximum

Wild soybean (Glycine soja Sieb. & Zucc.), the progenitor of cultivated soybean (Glycine max (L.) Merr.), is widely distributed in the Sino-Japanese Floristic Region (SJFR). Therefore, it is an excellent model organism to study the effect of Quaternary climatic changes on the distribution and migration of plant taxa in the SJFR. To investigate the phylogeography of G. soja, a total of 632 individuals representing 52 populations throughout the species distribution range were genotyped by using the sequencing data of a nuclear locus, AF105221, and a chloroplast locus, trnQ-rps16. We detected a total of 23 haplotypes from two loci, including five common and 18 rare haplotypes. Among them, 17 rare haplotypes were limited to Northeast Asia (Northeast China (NEC) and Korea) and the Yangzi River basin (middle and downstream of the Yangzi River (MDYR) and the eastern end of Southwest China (SWC)). Moreover, two common haplotypes were detected throughout the species distribution wide range. All the haplotypes from Japan and the Korean peninsula were also found in China. The haplotype distribution patterns of the two loci suggested that Northeast Asia (NEC and Korea) and the Yangzi River basin (MDYR and the eastern end of SWC) might have been the refugia for G. soja during the Quaternary glacial period, and G. soja expanded rapidly after the end of the Last Glacial Maximum. There was a land bridge between East China, the Korean peninsula, and Japan that permitted gene flow among populations of these regions in the ice age during the Quaternary.

Molecular phylogeography of four endemicSagittariaspecies (Alismataceae) in the Sino-Japanese Floristic Region of East Asia

To reveal the role of climate oscillations of the Quaternary in forming the contemporary plant diversity in the temperate Sino-Japanese Floristic Region of mainland China, we assess the phylogeographical patterns of four Sagittaria species in the region using sequence data from plastid DNA non-coding regions (psbA-trnH, the rpl16 intron and trnC-ycf6) and the internal transcribed spacers of nuclear ribosomal DNA (nrITS). Based on both datasets, the divergence time among the four studied species was estimated to fall in the Late Tertiary (plastid DNA: 7.1–13.7 Mya; ITS: 11.1–16.1 Mya). The ancestral distribution analyses revealed that regions with a great diversity in topography, climate and ecological conditions, e.g. the Hengduan Mountains, Central China and East China, were the areas where the endemics originated. Mismatch distribution analyses revealed that each species had experienced a range expansion in response to Quaternary climatic oscillations. Our findings contradict the hypothesis of Quaternary origins of the endemic Sagittaria spp.; we support the view that modern species in the Northern Hemisphere originated mostly during the Tertiary. Range expansion may have profoundly modified the current distribution ranges of Sagittaria species in the Sino-Japanese Floristic Region. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 00, 000–000.

Determination of allelopathic potentials in plant species in Sino-Japanese floristic region by sandwich method and dish pack method

&lt;p&gt;The Sino-Japanese Floristic Region appears as one of the major centers of development of higher plants. This region have been relevant for the study of evolution and systematics of many flowering plants. The taxonomic richness of endemic plant species in this region have survived several years of extreme climate conditions. Endemic mountainous plant species that have survived extreme climate conditions are of allelopathic and medicinal interest. For this reason, 251 plant species collected from the Sino-Japanese Floristic Region were screened for allelopathic plant species. Sandwich method and dish pack method were respectively used to screen plant leaf leachates and volatile materials with lettuce (&lt;em&gt;Lactuca sativa&lt;/em&gt; CV. Great Lakes 366) as receptor plant. Among the 84 species that showed inhibitory effect on lettuce radicle elongation in our sandwich bioassay, &lt;em&gt;Photinia glabra &lt;/em&gt;showed complete inhibition of lettuce radicle elongation (0% radicle elongation). In the dish pack bioassay, &lt;em&gt;Photinia glabra&lt;/em&gt;, &lt;em&gt;Liquidambar styraciflua&lt;/em&gt;, and &lt;em&gt;Cinnamomum camphora&lt;/em&gt; (90.6%, 61.4%, and 50.2% respectively) were among the nine species that were observed with strong inhibitory effect on lettuce radicle growth. On the other hand, nine other species promoted lettuce radicle growth when compared to the control. &lt;em&gt;Aesculus turbinata&lt;/em&gt; and &lt;em&gt;Quercus gilva&lt;/em&gt; were the species with the highest growth stimulatory effect (33.0% and 16.1% respectively). We hereby present &lt;em&gt;Photinia glabra &lt;/em&gt;as an allelopathic candidate species for both leachate and volatile compounds.&lt;/p&gt;

English

Conservation studies of 45 threatened medicinal plants were carried out for assessment of their conservation status, threats and recommendations growing in Mankial valley Hindukush Range Pakistan. Phytogeographically, the valley is present in the Sino Japanese floristic region and is a hot spot of endemism. A total of 45 taxa belonging to 35 families and 43 genera were collected and evaluated which include 13 (28.88%) vulnerable, 21 (46.66%) endangered and 11 (24.44%) critically endangered species. The number of plants scored with reference to its ecological amplitude and calculated historical distribution were compared with the IUCN criteria for threatened categories Version 3.1. The information regarding ‘conservation status’, threats and recommendations of the species were collected from the entire valley at different localities by filling questionnaire form 300 respondents including 260 male and 40 female. Mankial valley being naturally gifted with tremendous biodiversity, altitudinal and topographic variations is exposed to increasing human pressure, social injustice and low literacy rate that are destabilizing the biodiversity status especially species survival, habitat and ecosystem. According to the present studies, various parameters are contributing to make the important medicinal plants threatened including over exploitation (75.55%), fuel wood usage (35.55%), habitat loss (35.55%), over grazing (28.88%), deforestation (15.55%), use as timber (4.44%), bark usage (4.44%) and use as furniture (4.44%). Moreover, unsustainable utilization of plant natural resources and unscientific agricultural practices are the main threats to the ‘plant biodiversity’ growing in the valley. Therefore, studies regarding conservation status, threats and recommendations of threatened medicinal plants of Mankial Valley were proposed. Key words: Conservation, deforestation, ecosystem, Hindukush Range, Mankial valley, over grazing.

Reseach of plant diversity in the Sino-Japanese floristic region

Reseach of plant diversity in the Sino-Japanese floristic region

Phylogenetic relationship in the genus Panax: inferred from chloroplast trnK gene and nuclear 18S rRNA gene sequences.

Chloroplast trnK gene and nuclear 18S rRNA gene sequences of 13 Panax taxa, collected mainly from Sino-Japanese floristic region, were investigated in order to construct phylogenetic relationship and to assist taxonomic delimitation within this genus. The length of trnK gene sequence varied from 2537 bp to 2573 bp according to the taxa, whereas matK gene sequences, embedded in the intron of trnK gene, were of 1512 bp in all taxa. Species-specific trnK/ matK sequence provided much insight into phylogeny and taxonomy of this genus. 18S rRNA gene sequences were of 1808 or 1809 bps in length, only 9 types of 18S rRNA sequences were observed among 13 taxa. Parsimony and neighbor-joining analyses of the combined data sets of trnK-18S rRNA gene sequences yielded a well-resolved phylogeny within genus Panax, where three main clades were indicated. P. pseudoginseng and P. stipuleanatus formed a sister group located at a basal position in the phylogenetic tree, which suggested the relatively primitive position of these two species. Monophyly of P. ginseng, P. japonicus (Japan) and P. quinquefolius, which are distributed in northern parts of Asia or America, was well supported (Northern Clade). The remaining taxa distributed in southern parts of Asia formed a relatively large clade (Southern Clade). The taxonomic debated taxa traditionally treated as subspecies or varieties of P. japonicus or P. pseudoginseng showed various nucleotide sequences, but all fell into one cluster. It might suggest these taxa are differentiated from a common ancestor and are in a period of high variation, which is revealed not only on morphological appearance, but also on molecular divergence. By comparing trnK and 18S rRNA gene sequences among 13 Panax taxa, a set of valuable molecular evidences for identification of Ginseng drugs was obtained.

On phytogeographical affinities of the forest floras between east China and Japan

The flora of the eastern China is the main part of Sino-Japanese floristic region. It shows from the analysis and comparison that the floristic relation of East China with Japan is closer than that with northeast China and Korea. The similarity indices of genera and species of seed plants in the two regions are very high, being 72.6% and 43.3% respectively. The structure and species composition of broad-leaved evergreen forests in the two regions are also similar, and there exist many corresponding communities, such as the forests of Castanopsis carlesii and C. sieboldii. Many plants in East China are conspecific with those in Japan, such as Cercidiphyllum japonicum, Magnolia sieboldii, Nandina domestica etc. Though the genera of Ginkgo, Liriodendron, Sassafras etc. existing now in China are extinct from Japan, their fossils have been discovered from the Tertiary strata in Japan. It seems to indicate that the phytogeographical affinities between East China and Japan are closer in ancient time than it is now, and both of the forest floras originated from the same flora. The flora in Japan did not evolve independently until it separated from Chinese continent and drifted northeastwards in the late period of the Tertiary.