Nong Van Duy

A new combination and a new species in Phlegmariurus (Herter) Holub (Lycopodiaceae) from Southern Vietnam

ABSTRACT A new combination is proposed for Phlegmariurus (Herter) Holub (Lycopodiaceae): P. obovalifolius (Bonap.) V.T. Tran & N.V. Duy, comb. nov., and a new species of Phlegmariurus, P. lancifolius V.T. Tran & N.V. Duy, sp. nov., from southern Vietnam, is described and illustrated. It is distinguished from the closely related P. obovalifolius (Bonap.) V.T. Tran & N.V. Duy, comb. nov., by its leaves lanceolate, apex acuminate-acute, 1.1-1.5 × 0.4-0.6 cm, sporophyll cuneiform or broadly ovate, c. 2 × 2 mm, apex apiculate with acuminate tip, c. 2 mm, sporangia reniform.

Flavonoids isolated from Dipterocarpus obtusifolius

Five flavonoids including tiliroside ( 1 ), kaempferol 3- O -(2¢¢,6¢¢-di- O -( E )- p -coumaroyl- β -D-glucopyranoside) ( 2 ), myricetin ( 3 ), myricitrin ( 4 ), and myricetin 3- O - α- arabinofuranoside ( 5 ) have been isolated and identified from the leaves of Dipterocarpus obtusifolius . Their chemical structures were elucidated by spectroscopic methods including NMR and MS, and by comparison with the literature data. All these compounds were isolated from this plant for the first time.

Genetic diversity of Panax vietnamensis var. fuscidiscus K. Komatsu, s. Zhu & S.Q. cai population in western north of vietnam detected by inter simple sequence repeat markers

Panax vietnamensis var. fuscidiscus is a precious medicinal plant which was recently discovered in Sin Ho and Muong Te district, Lai Chau province of Vietnam. Over exploitation of the species in the native habitat poses a serious threat to its existence. Adequate information on the nature and the extent of genetic diversity in this important species is required for developing suitable strategy for its conservation. In this study, inter simple sequence repeat markers were employed to investigate the genetic diversity and variability of 46 individuals belonging to a naturally distributed population of this variety in Vietnam. Genetic diversity at the population level was high (He = 0.2300, I = 0.3665, and PPB = 96.98 %). The group of mature individuals possessed the higher genetic diversity (HeO = 0.2291, IO = 0.3563, and PPBO = 84.34 %) as compared to group of young individuals (HeY = 0.2086, Iy = 0.3291, and PPBY = 81.5 %). The intergroup gene differentiation was high (GST = 0.0499) with the genetic distance among groups was 0.0298. The similarity coefficient among mature individuals was more moderate (Maximum = 0.873, Minimum = 0.614 and Average = 0.741) than among young individuals (Maximum = 0.916, Minimum = 0.596 and Average = 0.759). Otherwise, the number of discovered individuals was small, distribution area is narrow habitats, and the population showed the reduction in genetic diversity due to the human affects in the habitat and over-exploitation. Results on genetic diversity and variability showed that the investigated population has coped with the risk of decline and needed to be protected.

Genetic diversity of Panax stipuleanatus Tsai in North Vietnam detected by inter simple sequence repeat (ISSR) markers

ABSTRACT Panax stipuleanatus Tsai is a type of medicinal plant within north-west Vietnam. In this study, inter simple sequence repeat markers were employed to investigate the genetic diversity of naturally distributed populations classified by habitat for this species. Genetic diversity at the species level was moderate (HeT = 0.254; PPBT = 96.02%). Genetic diversity was not equal in two populations. The result showed higher population genetic diversity in the Lao Cai region (HeBX = 0.266; PPBBX = 91.48%) as compared to those located in Lai Chau region (HeHT = 0.235; PPBHT = 84.66%). The interpopulation gene differentiation was small (GSTP = 0.03) with the genetic distance among populations was DP = 0.0103. Gene flow within populations was as high as Nm = 7.36.

A survey of Dendrobium Sw. sect. Formosae (Benth. & Hook.f.) Hook.f. in Cambodia, Laos and Vietnam

ABSTRACT This taxonomic survey of Dendrobium section Formosae in the flora of Cambodia, Laos and Vietnam includes 19 species (Dendrobium bellatulum Rolfe, D. cariniferum Rchb.f., D. chapaense Aver., D. christyanum Rchb.f., D. daklakense Tich, Schuit. & J.J. Verm., D. draconis Rchb.f., D. infundibulum Lindl., D. kontumense Gagnep., D. longicornu Lindl., D. multilineatum, D. ochraceum De Wild., D. roseiodorum Sathap., T.Yukawa & Seelanan, D. scabrilingue Lindl., D. senile E.C.Parish & Rchb.f., D. suzukii T.Yukawa, D. trankimianum T.Yukawa, D. trigonopus Rchb.f., D. wattii (Hook.f.) Rchb.f., D. williamsonii Day & Rchb.f.) hitherto recorded from these countries. It includes a key for species identification and updated information on species nomenclature, morphology, phenology, ecology, distribution and tentative conservation status.