A new species of Typhonium (Araceae) from Vietnam.

Typhoniumobtusum is described as a new species endemic to Vietnam. It is unique in the genus in having an oblong-elliptic spathe limb with an obtuse apex and yellowish-greenish filiform staminodes with a down-curved acumen. The ecology, distribution and assessment of the conservation status of the new taxon, as well as a key to all known Typhonium species in Vietnam, are provided.

Morusacerane: A new gammacerane triterpenoid from the trunk of Morus Alba linn. with α-glucosidase inhibitory activity.

This phytochemistry investigation on the trunk of Morus alba L. resulted in the isolation of three triterpenoids, including a new gammacerane triterpenoid - morusacerane (1); along with two known compounds of betulinic acid (2) and ursolic acid (3). The structure elucidation was thoroughly conducted based on 1D, 2D-NMR and HRESIMS spectra, followed by a comparison with existing literatures. The evaluation on α-glucosidase inhibitory exhibited the great potential of the application of these isolated compounds in diabetes treatments. The results show that morusacerane (1), betulinic acid (2), and ursolic acid (3) demonstrate the strong inhibitory with the IC50 values of 106.1, 11.12, and 7.20 µM, respectively. All of these compounds interacted well with the allosteric site enzyme α-glucosidase MAL32 through H-bonds and hydrophobic interaction.

trnL-F is a powerful marker for DNA identification of field vittarioid gametophytes (Pteridaceae).

BACKGROUND AND AIMS: The gametophyte phase of ferns plays an important role in habitat selection, dispersal, adaptation and evolution. However, ecological studies on fern gametophytes have been impeded due to the difficulty of species identification of free-living gametophytes. DNA barcoding provides an alternative approach to identifying fern gametophytes but is rarely applied to field studies. In this study, an example of field vittarioid gametophyte identification using DNA barcoding, which has not been done before, is given. METHODS: A combination of distance-based and tree-based approaches was performed to evaluate the discriminating power of three candidate barcodes (matK, rbcL and trnL-F) on 16 vittarioid sporophytes. Sequences of the trnL-F region were generated from 15 fern gametophyte populations by tissue-direct PCR and were compared against the sporophyte dataset, using BLAST. KEY RESULTS: trnL-F earns highest primer universality and discriminatory ability scores, whereas PCR success rates were very low for matK and rbcL regions (10·8 % and 41·3 %, respectively). BLAST analyses showed that all the sampled field gametophytes could be successfully identified to species level. Three gametophyte populations were also discovered to be living beyond the known occurrence of their sporophyte counterparts. CONCLUSIONS: This study demonstrates that DNA barcoding (i.e. reference databasing, tissue-direct PCR and molecular analysis), especially the trnL-F region, is an efficient tool to identify field gametophytes, and has considerable potential in exploring the ecology of fern gametophytes.

Langbiangia, a new genus of Gesneriaceae endemic to Langbiang Plateau, southern Vietnam and a taxonomic endeavor to achieve key targets of the post-2020 global biodiversity framework.

Situated in the southern end of the Annamite Mountain Range, Langbiang Plateau is a major biodiversity hotspot of southern Vietnam known for high species diversity and endemicity. To achieve effective conservation, parts of the plateau were designated as the Langbiang Biosphere Reserve, an UNESCO World Network aiming to improve relationships between inhabitants and their environments. Amongst the rich endemic flora of the plateau are three gesneriads ascribed to Primulina, a calciphilous genus with high species diversity in the vast limestone karsts stretching from southern China to northern Vietnam. However, a recent phylogenetic study questioned the generic placement of the Langbiang Primulina, corroborating with observations on the geographical distribution, habitat preference, and phyllotaxy of the three species. Based on phylogenetic analyses of nuclear ITS and plastid trnL-F DNA sequences of a comprehensive sampling covering nearly all genera of the Old World Gesneriaceae, we demonstrate that the three Langbiang Primulina species form a fully supported clade distantly related to other Primulina. As this clade is biogeographically, ecologically, morphologically, and phylogenetically distinct worthy of generic recognition, we propose to name it Langbiangia gen. nov. to highlight the rich and unique biodiversity of the Langbiang Plateau. By means of this taxonomic endeavor, we are hoping to raise the conservation awareness of this biodiversity heritage of southern Vietnam and promote the importance of Langbiang Biosphere Reserve that is crucial for achieving action-oriented global targets of the post-2020 global biodiversity framework (GBF) of the UN Convention on Biological Diversity (CBD)-effective conservation and management of at least 30% of biodiverse terrestrial, inland water, and costal and marine areas by 2030-that has been agreed at the COP15 in Montréal in December 2022.

Isotremaputalengense, a new species of Aristolochiaceae from northern Vietnam and two new combinations in Isotrema.

Isotremaputalengense Luu, Q.B.Nguyen & H.C.Nguyen is described as a new species from northern Vietnam. It looks most morphologically like I.wardianum but is distinguishable by a combination of different leafy and floral characters. Morphological comparison between the new plant and closest species is provided. In addition, combinations of two recently described Aristolochia species are made, namely Isotremavuquangense (T.V.Do) Luu, Q.B.Nguyen & H.C.Nguyen and Isotremayachangense (B.G.Huang, Yan Liu & Y.S.Huang) Luu, Q.B.Nguyen & H.C.Nguyen.

Primulinascutellifolia, a new species of Gesneriaceae from southern Vietnam.

Primulinascutellifolia is described as a new species from Khanh Hoa Province, southern Central Vietnam. It is distinct in the genus in having scutellate leaves that make it a highly potential ornamental plant. The new species looks like P.annamensis in general shapes, sizes and colours of habit, inflorescence, flower, and leaf but is distinguishable by adaxially glabrous and abaxially strigose leaves with serrate margins, scutellate leaf blade and appressed downwards tomentose petiole, sparsely glandular hairs on apical 1/2 of the gynoecium and trapeziform one-lipped stigma with slightly emarginated apex.

Comparative Analysis of Plastid Genomes in the Non-photosynthetic Genus Thismia Reveals Ongoing Gene Set Reduction.

Heterotrophic plants provide intriguing examples of reductive evolution. This is especially evident in the reduction of their plastid genomes, which can potentially proceed toward complete genome loss. Several milestones at the beginning of this path of degradation have been described; however, little is known about the latest stages of plastome reduction. Here we analyze a diversity of plastid genomes in a set of closely related non-photosynthetic plants. We demonstrate how a gradual loss of genes shapes the miniaturized plastomes of these plants. The subject of our study, the genus Thismia, represents the mycoheterotrophic monocot family Thismiaceae, a group that may have experienced a very ancient (60-80 mya) transition to heterotrophy. In all 18 species examined, the plastome is reduced to 14-18 kb and is highly AT-biased. The most complete observed gene set includes accD, seven ribosomal protein genes, three rRNA, and two tRNA genes. Different clades of Thismia have undergone further gene loss (complete absence or pseudogenization) compared to this set: in particular, we report two independent losses of rps2 and rps18.

Forest characteristics and population structure of Glyptostrobus pensilis, a globally endangered relict species of southeastern China.

The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained unknown up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are relatively healthier than those in Vietnam.

Author Correction: Identifying long-term stable refugia for relict plant species in East Asia.

In the original version of this Article, an incorrect sample size was provided for the number of relict species (443 instead of 442) and the number of relict forests (423 instead of 422). These errors have been corrected in both the PDF and HTML versions of the Article.

Identifying long-term stable refugia for relict plant species in East Asia.

Today East Asia harbors many "relict" plant species whose ranges were much larger during the Paleogene-Neogene and earlier. The ecological and climatic conditions suitable for these relict species have not been identified. Here, we map the abundance and distribution patterns of relict species, showing high abundance in the humid subtropical/warm-temperate forest regions. We further use Ecological Niche Modeling to show that these patterns align with maps of climate refugia, and we predict species' chances of persistence given the future climatic changes expected for East Asia. By 2070, potentially suitable areas with high richness of relict species will decrease, although the areas as a whole will probably expand. We identify areas in southwestern China and northern Vietnam as long-term climatically stable refugia likely to preserve ancient lineages, highlighting areas that could be prioritized for conservation of such species.