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25 June 2021, Volume 43 Issue 03
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  • Articles
    Spatial phylogenetics of two topographic extremes of the Hengduan Mountains in southwestern China and its implications for biodiversity conservation
    Yazhou Zhang, Lishen Qian, Daniel Spalink, Lu Sun, Jianguo Chen, Hang Sun
    2021, 43(03):  181-191.  doi:10.1016/j.pld.2020.09.001
    Abstract ( 179 )   HTML ( )   PDF (18333KB) ( 363 )   Save
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    Previous attempts to elucidate the drivers of speciation mechanisms and spatial distribution patterns of biodiversity in mountain regions have treated different floras within a single geological region as one flora, ignoring the potential contributions of high habitat/ecosystem heterogeneity. Furthermore, current conservation strategies largely focus on forest ecosystems and/or specific flagship species, ignoring marginal ecosystems, leaving species in these ecosystems at risk. Here, we compared the spatial patterns of biodiversity and the potential drivers of these patterns in the river valley and subnival ecosystems of the Hengduan Mountains region (HDM) in southwestern China. Specifically, we compared spatial patterns of diversity, endemism, and threatened species in these ecosystems based on both traditional measurements and recent phylogenetic approaches. We then examined how those patterns were related to environmental factors and human activity in these same regions. We found that the middle-southern HDM supports the highest diversity and endemism for the river valley and subnival ecosystems; however, the distribution patterns of neo- and paleo-endemism in these two ecosystems differ. Regression models indicate that habitat diversity and paleo-climatic fluctuation are important drivers of diversity and endemism for these two ecosystems. Temperature and precipitation, however, showed different influences on the spatial patterns in different ecosystems. Categorical analysis of neo- and paleoendemism (CANAPE) indicated that most endemism centers are not covered by current nature reserves. Moreover, the intensity of human activity is highest in the southern and southeastern HDM, which coincides with the distribution patterns of diversity, mixed-endemism and high-priority (and threatened) species. These findings suggest that different floras within a single geographic/floristic region respond differently to environmental factors and show different spatial phylogenetic patterns. We, therefore, recommend that future research into the drivers of biodiversity consider the contributions of various ecosystem types within a single geological region. This study also provides a theoretical basis for protecting habitat diversity. Our work confirms that current conservation efforts are insufficient to protect ecosystem diversity in the river valley and subnival ecosystems of the Hengduan Mountains. Therefore, we recommend the establishment of nature reserves in the regions identified in this study; furthermore, we strongly recommend improving current and establishing new management policies for biodiversity conservation in this region.
    Plastid phylogenomics and biogeography of the medicinal plant lineage Hyoscyameae (Solanaceae)
    Feng-Wei Lei, Ling Tong, Yi-Xuan Zhu, Xian-Yun Mu, Tie-Yao Tu, Jun Wen
    2021, 43(03):  192-197.  doi:10.1016/j.pld.2021.01.005
    Abstract ( 125 )   HTML ( )   PDF (2609KB) ( 51 )   Save
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    The cosmopolitan family Solanaceae, which originated and first diversified in South America, is economically important. The tribe Hyoscyameae is one of the three clades in Solanaceae that occurs outside of the New World; Hyoscyameae genera are distributed mainly in Europe and Asia, and have centers of species diversity in the Qinghai-Tibet Plateau and adjacent regions. Although many phylogenetic studies have focused on Solanaceae, the phylogenetic relationships within the tribe Hyoscyameae and its biogeographic history remain obscure. In this study, we reconstructed the phylogeny of Hyoscyameae based on whole chloroplast genome data, and estimated lineage divergence times according to the newly reported fruit fossil from the Eocene Patagonia, Physalis infinemundi, the earliest known fossil of Solanaceae. We reconstructed a robust phylogeny of Hyoscyameae that reveals the berry fruit-type Atropa is sister to the six capsule-bearing genera (Hyoscyameae sensu stricto), Atropanthe is sister to the clade (Scopolia, Physochlaina, Przewalskia), and together they are sister to the robustly supported Anisoduse-Hyoscyamus clade. The stem age of Hyoscyameae was inferred to be in the Eocene (47.11 Ma, 95% HPD:36.75-57.86 Ma), and the crown ages of Hyoscyameae sensu stricto were estimated as the early Miocene (22.52 Ma, 95% HPD:15.19-30.53 Ma), which shows a close correlation with the rapid uplift of the Qinghai-Tibet Plateau at the Paleogene/Neogene boundary. Our results provide insights into the phylogenetic relationships and the history of the biogeographic diversification of the tribe Hyoscyameae, as well as plant diversification on the Qinghai-Tibet Plateau.
    Plastome and phylogenetic relationship of the woody buckwheat Fagopyrum tibeticum in the Qinghai-Tibet Plateau
    Bibo Yang, Liangda Li, Jianquan Liu, Lushui Zhang
    2021, 43(03):  198-205.  doi:10.1016/j.pld.2020.10.001
    Abstract ( 115 )   HTML ( )   PDF (8415KB) ( 41 )   Save
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    The phylogenetic position of the monotypic woody Parapteropyrum (Polygonaceae) remains controversial. Parapteropyrum has been thought to be closely related to the woody genera of the tribe Atraphaxideae, although some evidence indicates that it nests within the herbal buckwheat genus Fagopyrum of tribe Polygoneae. In this study, we used plastome data to determine the phylogenetic position of Parapteropyrum (Fagopyrum) tibeticum. Different reference species were used to assemble plastomes of three species currently placed in the tribe Ataphaxideae:Parapteropyrum (Fagopyrum) tibeticum, Atraphaxis bracteata and Calligonum ebinuricum. Once assembled, plastomes were characterized and compared to plastomes of 12 species across the family Polygonaceae. Phylogenetic analyses of Polygonaceae were performed using whole plastome, all plastome genes, and single-copy genes. Plastomes assembled using different reference plastomes did not differ; however, annotations showed small variation. Plastomes of Parapteropyrum (Fagopyrum) tibeticum, A. bracteata and C. ebinuricum have the typical quadripartite structure with lengths between 159,265 bp and 164,270 bp, and a total number of plastome genes of about 130. Plastome microsatellites (SSR) ranged in number from 48 to 77. Maximum Likelihood and Bayesian analyses of three plastome data sets consistently nested Parapteropyrum within the genus Fagopyrum. Furthermore, our analyses indicated that sampled woody genera of the family Polygonaceae are polyphyletic. Our study provides strong evidence that the woody Parapteropyrum tibeticum, which is distantly related to woody genera sampled here, should be taxonomically placed under Fagopyrum as Fagopyrum tibeticum.
    A preliminary phylogenetic study of Paraphlomis (Lamiaceae) based on molecular and morphological evidence
    Ya-Ping Chen, Ang Liu, Xun-Lin Yu, Chun-Lei Xiang
    2021, 43(03):  206-215.  doi:10.1016/j.pld.2021.03.002
    Abstract ( 92 )   HTML ( )   PDF (16761KB) ( 34 )   Save
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    Paraphlomis is a genus of Lamiaceae with about 30 species distributed mainly in subtropical China. In this study, we carried out the first molecular phylogenetic analyses to elucidate the relationships within the genus based on two nuclear and four plastid DNA regions. Our results, which recovered a species of Matsumurella within Paraphlomis, indicate that the genus is not monophyletic. The two sections and most of the series previously described within the genus are also shown to be polyphyletic. Combining with morphological evidence, our study indicates that nutlet morphology rather than calyx morphology is of phylogenetic value for the infrageneric classification of Paraphlomis. Moreover, P. jiangyongensis, a new species from southern China, is here described, and P. coronata, formerly treated as a variety of P. javanica, is here resurrected as a distinct species within the genus.
    Quantitative classification of Camellia japonica and Camellia rusticana (Theaceae) based on leaf and flower morphology
    Harue Abe, Hiroki Miura, Yoshitaka Motonaga
    2021, 43(03):  216-224.  doi:10.1016/j.pld.2020.12.009
    Abstract ( 142 )   HTML ( )   PDF (4353KB) ( 34 )   Save
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    In Japan, Camellia japonica and Camellia rusticana are naturally distributed. Despite differences in their habitats and morphologies, they have been classified by various researchers as either varieties, subspecies, or species. The taxonomic position of C. japonica and C. rusticana remain unclear because morphological comparisons have been restricted to limited areas and quantitative data are scarce. C. rusticana grows in snowy places, unlike C. japonica. While C. japonica displays ornithophily, C. rusticana displays entomophily. Both species have adapted to different growing environments and pollinators, which have altered the morphology of flowers and leaves. We therefore quantitatively estimated the differentiation between these two taxa by comparing the morphologies of leaf hypodermis, flower form, petal color, and filament color in twenty populations. Our findings allowed us to differentiate these two species by the presence or absence of a leaf hypodermis. We also discovered an intermediate type of leaf hypodermis, which might also be caused by hybridization. Principal component analysis (PCA) indicated that the flower morphologies between these species were significantly different. The petal and filament colors were also significantly different. Our quantitative analysis suggests that speciation caused by differences in both pollinators and environment is one of the factors involved in this group. These findings in C. japonica and C. rusticana help to explain speciation processes for other species as well.
    Genetic diversity and structure of the endemic and endangered species Aristolochia delavayi growing along the Jinsha River
    Yu-Long Yu, Hui-Chun Wang, Zhi-Xiang Yu, Johann Schinnerl, Rong Tang, Yu-Peng Geng, Gao Chen
    2021, 43(03):  225-233.  doi:10.1016/j.pld.2020.12.007
    Abstract ( 123 )   HTML ( )   PDF (5421KB) ( 39 )   Save
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    The traditional medicinal plant, and endangered species Aristolochia delavayi (Aristolochiaceae) is an endemic species in China and occurs in the warm and dry areas along the Jinsha river. It is also a specific host of the larvae of Byasa daemonius, a vulnerable butterfly. In this study, 15 pairs of polymorphic microsatellite primers of A. delavayi were designed and screened based on the Simple Sequence Repeats (SSR) loci found by using the results of genome skimming. Based on these 15 SSR markers, the genetic diversity and structure of 193 individuals from ten natural populations were analyzed in detail. In comparison to other endemic and endangered plants in the region, the population of A. delavayi possess a relatively high genetic diversity (He = 0.550, I = 1.112). AMOVA analysis showed that 68.4% of the total genetic diversity was within populations and 31.6% of the variation occurred among populations. There was a significant genetic differentiation among natural populations of A. delavayi detectable, with low gene flow (Nm = 0.591). This might be attributed to geographical barriers and limited seed dispersal. To test the isolation by distance (IBD), we performed Mantel test, which showed a significant correlation between the geographic and genetic distances. In order to cope with the possible biases caused by IBD, we additionally performed Bayesian genetic cluster analyses and principal coordinate analysis (PCoA). The final cluster analysis revealed three groups with distinct geographical distribution. Habitat fragmentation and limited gene flow between these populations may be the main reasons for the current genetic structure. For conservation of this species, we suggest to divide its populations into three protection management units, with subsequent focus on the Yongsheng and Luquan populations which experienced a genetic bottleneck event in the past.
    Dispersal and germination of winged seeds of Brandisia hancei, a shrub in karst regions of China
    Yongquan Ren, Chengling Huang, Jiaming Zhang, Yongpeng Ma, Xiaoling Tian
    2021, 43(03):  234-238.  doi:10.1016/j.pld.2020.11.006
    Abstract ( 93 )   HTML ( )   PDF (1612KB) ( 27 )   Save
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    Brandisia hancei (Paulowniaceae) is a widely distributed shrub in karst regions in southwestern China. Its seeds have a membranous wing, and they mature just before the rainy season begins. To assess the effect of the wing on seed dispersal and germination of B. hancei, we measured the dispersal distance at varying wind speeds and release heights, falling duration from different release heights, floating duration on still water, rates of imbibition of water, and drying and soil adherence to seeds. Germination experiments were conducted on intact and de-winged seeds immediately after harvest. The wing increased the falling duration in still air and the floating ability on water. Dispersal distance of winged and de-winged seeds did not differ at a wind speed of 2.8 m s-1, but at 3.6 and 4.0 m s-1 dispersal distances were greater for de-winged than for winged seeds. Seed wing had little effect of absorption and retention of water, but significantly increased soil adherence to the seeds. Mature seeds were non-dormant and germinated to over 90% with a mean germination time of about 10 days. By combining the environmental conditions in karst habitat with the seed traits of B. hancei, we conclude that dispersal and germination of winged seeds are adapted to the precipitation seasonality in heterogeneous habitats absence of soil.
    An ethnobotanical study of forage plants in Zhuxi County in the Qinba mountainous area of central China
    Jun Yang, Jifeng Luo, Qiliang Gan, Leiyu Ke, Fengming Zhang, Hairu Guo, Fuwei Zhao, Yuehu Wang
    2021, 43(03):  239-247.  doi:10.1016/j.pld.2020.12.008
    Abstract ( 154 )   HTML ( )   PDF (2082KB) ( 162 )   Save
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    In the Qinba mountainous area of Central China, pig farming has a significant impact on the growth of the rural economy and has substantially increased farmer incomes. Traditional knowledge plays an important role in the selection of forage plant species for pig farming by local people. This study aimed to identify the forage plants used for pig feeding and to catalog indigenous knowledge regarding their use. During 2016 and 2017, ethnobotanical surveys and inventories were conducted in Zhuxi County, Hubei Province, China. Data were collected using semi-structured interviews, key informant reports, free listings, guided field walks, and participatory observations with 77 households in 16 villages in 13 towns/townships. The obtained data were analyzed using a relative frequency citation (RFC) index. Overall, 145 wild forage plants from 91 genera and 31 families were recorded. The most cited families were Asteraceae, Polygonaceae, Urticaceae, Amaranthaceae, Fabaceae, Cruciferae, Caryophyllaceae, and Lamiaceae. Whole plants (75.9%) and tender leaves (12.4%) were the most frequently used parts of the plants. Most of the forage plants were herbaceous (88.9%). Almost all forage plants could be collected throughout the year (62.7%). Raw and cooked were the two main preparation methods. The most frequently cited species were Taraxacum mongolicum, Bidens pilosa, Sonchus oleraceus, Pilea verrucosa, and Pilea pumila var. obtusifolia. A total of 14 species were identified as the top forage plants in Zhuxi County based on their RFC values (RFC value greater than 0.5). Local people possess rich traditional knowledge about the utilization and management of forage plants for pig feeding. However, the maintenance of this traditional knowledge may be seriously threatened by changes in pig feeding modes and the lack of successors. Appropriate strategies and action plans have been suggested for the conservation of traditional knowledge associated with biodiversity and the sustainable use of forage species resources. These include 1) taking targeted measures to protect forage resources and associated traditional knowledge; 2) strengthening research on the forage plants with the highest RFC values for nutritional value, digestibility, other functions, and ecological status; and 3) enhancing the identification of poisonous forage plants.
    Flavonoid scutellarin positively regulates root length through NUTCRACKER
    Xing Huang, Weiqi Li, Xudong Zhang
    2021, 43(03):  248-254.  doi:10.1016/j.pld.2020.08.001
    Abstract ( 113 )   HTML ( )   PDF (11668KB) ( 186 )   Save
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    Exploring approaches to regulate meristem is of special importance and broad interest. In this study, we found that the flavonoid scutellarin, which has a 6-hydroxyl and a 7-glucoside, increased root length through the transcription factor NUTCRACKER (NUC). This root lengthening disappeared in NUC-knockout and reappeared in NUC-rescue plants. Scutellarin induced NUC expression and promoted the division of cortex/endodermal initials. In contrast, naringenin, which has same chemical backbone but without 6-hydroxyl and with 7-hydroxyl group, showed the opposite or no effects. Our results demonstrate that scutellarin promotes root length through NUC-mediated regulatory pathways and reveal that flavonoids with and without the 6-hydroxyl and 7-glucoside have positive and negative effects on meristem size, respectively.