Genetic Diversity and Genetic Differentiation of Rheum palmatum by Chloroplast matK Sequences

Background: Rheum palmatum is a medically important plant in the Polygonaceae family. Its wild resources have been declining due to over-exploitation. It is important and urgent to investigate the genetic diversity for the conservation of R. palmatum. Methods: The Chloroplast DNA matK sequences were used to assess genetic diversity among and within populations in this species. The genetic diversity index was calculated by Dnasp, PERMUT and Arlequin 3.0 software, and a Neighbor-Joining (NJ)-tree was constructed by MEGA 5.0 software. Results: Nine haplotypes were obtained based on the matK sequence analysis in fifteen populations. We found a relatively high genetic diversity in species level (Hd = 0.7414), and the genetic diversity among populations (FST = 0.81582) was higher than that within populations (FSC = 0.69526) according to the AMOVA analysis. The genetic distance between populations ranged from 0 to 0.0044, which within populations ranged from 0 to 0.001761. There was a significant correlation between genetic distance and geographic distance (r = 0.601, P < 0.001) according to the SPSS analysis. Conclusion: The genetic diversity among populations was higher than that within populations due to geographic isolation and decline in gene flow among populations. This study is significant for further studies concerned with efficient collection and preservation of wild resource of R. palmatum.

Morpho-anatomical structure and DNA barcode of Sonchus arvensis L.

Wahyuni DK, Rahayu S, Purnama PR, Saputro TB, Suharyanto, Wijayanti N, Purnobasuki H. 2019. Morpho-anatomical structure and DNA barcode of Sonchus arvensis L. Biodiversitas 20: 2417-2426. Tempuyung or show thistle (Sonchus arvensis L.) belongs to the Asteraceae. Morpho-anatomy and DNA (Deoxyribonucleic Acid) barcoding of the plant correlates with species identification and metabolite synthesis. This research aims to look at morpho-anatomical structures and analyze the DNA barcode of Sonchus arvensis L (tempuyung). Three samples used for morpho-anatomical analysis are leaves, stems, roots, fruit, and seeds. Anatomical samples are made using the embedding method. DNA barcode uses multiple locus from plastid genome: rbcL and matK. Morpho-anatomical structure of tempuyung showed a similar structure of Sonchus genus. The stem presents in the intercellular space, whereas the roots and leaves present in the vascular tissue and the seeds. Fruits present in each part of the body. Tissues that formed root are epidermis, cortex, endoderm, and stele. Tissues that formed stem are epidermis, cortex, and stele. Tissues that formed leaf are epidermis, cortex, phloem, and xylem. Tissues that formed the fruit and seed are paranormal and sclerenchyma tissues. Sonchus arvensis sequence for rbcL has a similar 100% maximum identity to rbcL gene of S. arvensis, Sonchus asper, and Sonchus oleraceus, whereas Sonchus arvensis matK sequence has a similar 99.31% maximum identity to other S. arvensis matK sequences in BLAST system. These findings provide morpho-anatomical features and DNA barcoding for identification of S. arvensis. from others species in the same genus. Thus also can be considered as pharmaceutical standard.

Platanthera guangdongensis and P. zijinensis (Orchidaceae: Orchideae), two new species from China: Evidence from morphological and molecular analyses

Two new Platanthera (Orchidinae, Orchideae, Orchidoideae) species, P. guangdongensis and P. zijinensis, from the Guangdong Province in China are described and illustrated based on morphological and molecular analyses. Platanthera guangdongensis is leafless and resembles P. fujianensis, but it differs in terms of the shorter and/or smaller inflorescence, floral bract, dorsal sepal, lateral sepal, petal, and ligulate lip. Platanthera zijinensis is morphologically similar to P. minor, but it differs by the ovate-oblong to ovate floral bract, colour of flower, ovate dorsal sepal, oblong lateral sepal, ovate-oblong lip, and curved forward spur. The phylogenetic analyses based on nuclear ribosomal ITS and chloroplast (rbcL and matK) sequence data support that P. zijinensis and P. guangdongensis being sisters to each other and genetically sister to P. minor. The chloroplast rbcL of P. guangdongensis is a pseudogene, supporting its characterization as a holomycotrophic orchid.

Nymphoides aurantiaca (Dalzell) Kuntze, a new record of family Menyanthaceae for the flora of Vietnam

The newly recorded species, Nymphoides aurantiaca (Dalzell) Kuntze belonging to family Menyanthaceae, was discovered at some wetland areas in Lò Gò–Xa Mát National Park (Tân Biên, Tây Ninh). This species was found for the first time in 2003 during a research on wetland biodiversity and conservation funded by Tây Ninh Province’s Department of Science and Technology. Special morphological characteristics of the species include floating leaf blades, deeply cordate at base; flowers usually two per node; five dark yellow corollas with fimbriately toothed margins. This aquatic species inhabits standing water bodies such as shallow ponds, flooded lowlands with water depth of 20-40 cm, low turbidity and slightly acidic with pH values ranging from 5.4 to 6.0. The phylogenetic affinity between N. aurantiaca and other Nymphoides species was established based on matK sequence of chloroplast DNA.

Phylogenetic reassessment of Specklinia and its allied genera in the Pleurothallidinae (Orchidaceae)

The phylogenetic relationships within Specklinia (Pleurothallidinae; Orchidaceae) and related genera are re-evaluated using Bayesian analyses of nrITS and chloroplast matK sequence data of a wide sampling of species. Specklinia is found paraphyletic in the DNA based trees, with species alternatively assigned to Muscarella proven distinct, monophyletic and easily recognizable. Specklinia as such includes about 100 morphologically highly diverse species. Their phenotypic differences have prompted the creation of up to eleven generic names within this relatively small group. Here we show not only that these morphologically divergent species are closely related, but also that they can still be recognized by certain conserved morphological traits. The genera Acostaea, Areldia, Empusella, Cucumeria, Gerardoa, Pseudoctomeria, Sarcinula, Sylphia, Tribulago and Tridelta are found embedded within Specklinia, and therefore reduced under the synonymy of the latter. Specklinia is confirmed as sister to a clade that includes Platystele, Scaphosepalum and Teagueia. Five well-supported subgenera are proposed for Specklinia and are characterized both geographically and morphologically. The species belonging to each subgenus are listed. Incaea is synonymized with Dryadella, while Rubellia is reduced under Platystele. New combinations for several species are proposed. The criteria for the generic delimitation of Specklinia and other genera in the Pleurothallidinae are discussed.