Nong Van Duy’s research while affiliated with Vietnam Academy of Science and Technology and other places

Bamboos are widely distributed in a variety of habitats in the Central Highlands. Different researchers treat species differently, leading to ambiguous reporting of generic and infrageneric taxa. Following extensive research, this paper is an updated enumeration report on the bamboos that have been found there. The result has recorded 29 species of bamboo belonging to 15 genera. The Bambusoideae grow naturally in almost all regions, in an altitudinal range that extends from 200 m up to 2,160 m. Bamboo in the Central Highlands is distributed in three vegetation types: degraded natural forests in valleys and mountain gorges, along rivers (twenty-one species); primary forest, mixed with broadleaved trees (six species); and dry dipterocarp forest (two species).

The seventh paper of the series on orchid diversity in Vietnam includes descriptions of four species new to science (Goodyera umbonata, Myrmechis brachyscapa, Rhomboda obcordata, and Vietorchis proboscidea) and five new national records (Calanthe speciosa, Habenaria coultousii, Myrmechis urceolata, Paphiopedilum barbigerum var. barbigerum, and Peristylus affinis). Two new nomenclatural combinations, Rhomboda aurea (≡ Odontochilus aureus) and Odontochilus tonkinensis (≡ Anoectochilus tonkinensis), are proposed. Odontochilus putaoensis described from Myanmar and reported also from China and Laos is synonymized with Odontochilus umbrosus described 22 years earlier from Vietnam. Data on relevant synonyms and etymology are provided, along with morphological descriptions for the newly described species. For the species new to science and for the taxa reported for Vietnam for the first time, the information is given about studied specimens, ecology, phenology, distribution, and conservation status assessed according to the IUCN Red List Categories and Criteria, accompanied by brief taxonomic notes and illustrations.

A synopsis of the genus Mussaenda L. in Lam Dong province was made by mean of literature search, consultation of the herbarium specimens, and surveys of several localities through Lam Dong province. There are 10 species in genus Mussaenda L. in the total are found in Lam Dong province including: Mussaenda chevalieri Pit., Mussaenda densiflora H. L. Li, Mussaenda erosa Champ. ex Benth., Mussaenda hoaensis Pierre ex Pit., Mussaenda longipetala H. L. Li, Mussaenda philippica A. Rich., Mussaenda pubescens Ait. F., Mussaenda squiresii Merr., Mussaenda theifera Pierre ex Pit., Mussaenda thorelii Pit. Genus Mussaenda L. is present in almost all the forests of Lam Dong province from 180m to 1,800m a.s.l. At present, the environment is changing, therefore, solutions should be found to conserve and develop them as medicinal and ornamental species.

Paphiopedilum x dalatense is a beautiful orchid species with large flowers in variable colors and leaves covered with stripes and beautiful unseen mosaic spots. Recently, many people exploit this species, causing it becomes very rare. In this study, we studied the effects of various organic matter: potato, banana and tryptone, yeast powder, peptone on the growth and development of P. dalatense shoots as well as the effects of NAA and humic acid on in vitro rooting of this orchid were investigated. The research results showed that MS medium supplemented with 100 g/L banana in combination with 100 g/L potato (5,4 shoots/sample, 18,8 mm/shoot, 4,5 leaves/shoot, and shoots survival rate of 100%) or MS medium supplemented with 1 g/L peptone (4,19 shoots/sample, 15 mm/shoot, 4 leaves/bud, and 92% of shoots survival rate) were the best response for the shoot formation and development. In addition, the half strength MS culture medium supplemented with 1 mg/L NAA (5,2 leaves/sample, 4,6 roots/buds, 3,56 cm/root, and 100% rate for rooting) was the suitable medium for the in vitro rooting of P. dalatense. Being cultured on half strength MS medium supplemented with 2 mg/L humic acid, the rooting rate reached 100% with the greatest root number and the longest root (5 roots/shoots, 5,5 cm/root). The obtained results on the in vitro propagation on this orchid helps contribute to the conservation and increases the genotic pool of this precious wild orchid species, as well as the rapid multiplication of healthy plantlets serving the commercialization of precious orchid species.

Morphological leaf traits can be used to assess adaptive responses of plants to environmental conditions. To assess how the representation of Huperzia serrata leaf traits, such as leaf length (LL), leaf width (LW) and leaf area (LA) response to changes in mean annual temperature (MAT), sunshine duration (SuH), mean annual precipitation (MAP), air humidity (Hu), intraspecific variation of the morphological leaf traits of the species was analyzed along a geographical gradient of Vietnam. The results showed that among the three populations at the three sites, leaf sizes increased with MAT and MAP. Huperzia serrata, climatic factors, morphological leaf traits, Vietnam.

Dendrobium heterocarpum Lindl. is an endangered species which is currently used as ornamental pot plant for its beautiful flowers. An increase in collection for trade or any other purposes may lead to a dramatic decrease in the population of this species, thus becoming rare or endangered species in the near future. In this study, effects of plant growth regulators (BA, NAA, IAA, IBA, TDZ) and natural supplements (carrot, potato, and banana extracts) on protocorm like bodies (PLBs) formation; growth and development of shoot; and root regeneration of D. heterocarpum Lindl. as well as type of substrates on acclimatization and growth of seedlings were investigated. The results showed that PLBs formation was optimal on MS medium supplemented with 2.0 mg/L BA and 1.0 mg/L NAA (7.11 PLBs/explant; PLBs formation percentage of 68.9%) or MS medium supplemented with 1 mg/L TDZ and 0.5 mg/L NAA (7.29 PLBs/explant; PLBs formation percentage of 75.53%). For subculture, MS medium supplemented 1.5 mg/L BA and 60 g/L banana extract (22.40 shoots/explant; shoot length of 2 cm) was the most suitable for shoot regeneration and growth. Additionally, root formation was the most suitable on ½ MS medium supplemented with 1 mg/L NAA (4.4 roots/shoot; root length of 3.12 cm; root formation of 95.56%). Finally, the sufficiently rooted plantlets were transferred to greenhouse for hardening. After 60 days, coconut fiber substrate was the most suitable for seedling growth and development (with survival rate of 97.78%, root number of 5 and shoot length of 3.4 cm). The results of propagation in vitro Dendrobium heterocarpum Lindl. contribute to conservation and sustainable development as well as towards the rapid multiplication of seedlings for commercial commercialization of this wild orchid species.

Three taxa, Bulbophyllum cariniflorum var. orlovii (sect. Pleiophyllum), B. sonii (sect. Anisopetalon) and B. ustulata (sect. Brachystachya) are described as new for science. All of these novelties are local endemics of Vietnam. Additionally, four species, B. flavescens (sect. Aphanobulbon), B. ovatum (sect. Desmosanthes), B. physocoryphum (sect. Macrocaulia) and B. wendlandianum (sect. Cirrhopetalum) are recorded for the flora of Vietnam for the first time. These species are endemic of the Indochinese Peninsula in a broad sense, except for B. flavescens having wide distribution in western Malesia. Data on ecology, phenology, distribution, brief relevant taxonomic notes, as well as colour photographs and line drawings of the type and voucher specimens are provided for all reported taxa. Lectotypification is provided for B. wendlandianum.

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.

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.

Paphiopedilum villosum var. annamense Rolfe. is the attractive pot plant characterize by its larger and beautiful flower. Wild population of that orchid are now considered to be rare in nature as a result of habitat destruction and commercial preference. Thus, it is very important that actions should be taken to conserve this orchid before it becomes extinct. The information of genetic variation at both population and species levels is a scientific basic for species conservation. In this research, two populations of Paphiopedilum villosum var. annamense Rolfe were collected in Lam Dong province, Vietnam for analysing of genetic variation. RAPD directive was used to examine genetic variability in 20 individuals of two populations. The results showed that 25 bands were recorded from 12 specific identification primers. The percentages of polymorphic loci at species and population levels in the research were not high (Pt = 74.07%; P1 = 67.90%; P2 = 62.35%). However, in the first population, a higher percentage of polimorphic loci was observed as in the second one. Significant heterozygosity at both population and species levels was also low (HE1 = 0.23; HE2 = 0.18; and HEt = 0.25). The total gene diversity at the species level was partitioned primarily between two populations, as show by low GST= 0.17. Genetic distance between two populations was low (D12 = 0.079). In the orther hand, Genetic similarity coefficients between individuals in the general population were ranged from 0.57 to 0.91. The results suggested that the small population sizes in isolation had led to increase of inbred individuals within populations. Some solutions to the conservation and sustainable development have been mentioned.