Hoa Binh province is one of the best places for orchids in Vietnam. The climate and environment of Hoa Binh province are favorable for the development of orchids, especially rare indigenous ones. Dendrobium anosmum Lindl., which stands out because of the unique fragrance and colors, is one of the most popular varieties in Hoa Binh province. To meet the increasing demands of the industrial market as well as to contribute to the preservation and development of genetic resources of Dendrobium sp. in Hoa Binh province, propagating D. anosmum Lindl. is a crucial step. Plant tissue culture, which has been applied to improve reproducibility of orchids for many years, is still an effective method, especially for large-scale propagation. Studies on in vitro propagation of D. anosmum Lindl. from Hoa Binh province showed that growth regulators (BA, kinetin, α-NAA) did not have a significant effect on protocorm initiation because D. anosmum Lind. from Hoa Binh province already has a high rate of regeneration. However, MS medium + 1.0 mg/L kinetin + 0.5 mg/L α-NAA + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the optimal medium to increase shoot length. The MS medium + 1.0 g activated charcoal + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the most suitable medium for shoot growth—after 6 weeks of culture, the average shoot length was 1.09 cm, the average number of leaves was 6.13, the average number of roots was 3.17, and the average root length was 1.11 cm—about 3.3, 4.17, 3.41, and 1.67 times higher, respectively, than in the control (without activated charcoal).

Black cardamom (Amomum tsao-ko Crevost & Lemarié) is a spice plant of great commercial value in Vietnam, but with limited propagation ability. Its seeds are characterized by a thick and hard seed coat, a small endosperm, and a small embryo, which are the causes of the physical dormancy of the seeds and low germination. Attempts in this study to improve the germination rate and achieve uniform germination included mechanical scarification, immersion in hot or cold water, acid scarification, and the application of plant growth regulators. Although immersion of seeds in cold water and application of plant growth regulators (PGRs) (gibberellic acid (GA₃) and 1-naphtaleneacetic acid (NAA)) showed positive effects on seed germination and subsequent seedling growth, mechanical scarification provided the highest germination rate of black cardamom seeds (68.0%) and significantly shortened germination time (53.7 days) compared to control (16.0% and 74.7 days). On the other hand, an efficient micropropagation protocol has been established using shoot tip explants derived from in-vitro-grown seedlings. Murashige and Skoog (MS) medium supplemented with 4.0 mg/L 6-benzylaminopurine (BAP) + 0.5 mg/L NAA proved to be most suitable for rapid multiplication and rooting, providing a mean of 5.4 shoots per explant, 6.8 cm shoot length, and 16.2 roots per explant after 7 weeks of culture. Well-rooted black cardamom plantlets have been successfully adapted to ex vitro conditions. “Fasco” bio-soil was more suitable for acclimatization, with a 48.9% survival rate, 23.3 cm plant length, and 5.7 leaves per plant after 3 months of planting. Improved germination and multiplication protocols can be used to improve propagation performances and to develop elite of black cardamom planting material.

Sweet potato (Ipomoea batatas (L.) Lam), a member of the bindweed family (Convolvulaceae Juss.), is well known for its food, medicinal, and industrial values. It is estimated that more than 7000 sweet potato cultivars have been bred to date. Jewel sweet potato (I. batatas Lam cv. Jewel) is one of the most popular cultivars of sweet potato grown today because of its high nutritional value, delicious taste, and is suitable for all processing methods. However, little is known about the micropropagation of jewel sweet potato. The purpose of this paper was to study the effect of three important factors, including culture medium, plant growth regulators (PGRs), and artificial light sources, on the induction, proliferation, and growth of in vitro I. batatas ‘Jewel’ shoots obtained from the axillary bud and shoot tip explants. The different Murashige and Skoog (MS) salt levels (33%, 50%, 100%, and 150%) were used to study the influence of mineral treatment. To assess the influence of PGRs, we used 0.5 mg/L indole-3-acetic acid (IAA) combined with various cytokinins, including 0.5–2.0 mg/L 6-benzylaminopurine (BAP), 0.5–2.0 mg/L kinetin (Kn), and 0.1–1.0 mg/L thidiazuron (TDZ). On the other hand, the in vitro shoots were cultivated in a light room with different lighting conditions. Three lighting treatments (differences in the ratio between the red (R) and blue (B) spectra) were used. Research results have shown that the medium containing 50% MS salt concentration supplemented with 0.5 mg/L BAP or 0.5 mg/L Kn combined with 0.5 mg/L IAA was the most suitable for induction, proliferation, and growth of in vitro jewel sweet potato shoots. On the other hand, stem pieces bearing the axillary buds’ explants were determined to be suitable for the shoot induction. Using artificial light with different blue/red ratios also had a significant effect on the growth of explants and stimulates shoot or root formation.

Chicory (Chicorium intybus L.) is a perennial herb of the family Asteraceae, widely distributed in Asia and Europe, commonly used industrially as a raw material for extracting inulin because of a high content of inulin and biologically active compounds. Light conditions and plant growth regulators (PGRs) are two of many factors that affect the growth and inulin content of chicory callus. The aim of this work is to study the effect of PGRs and light conditions on proliferation and accumulation of inulin of chicory callus in vitro. In this study, we used semi-solid MS medium supplemented with different auxins (including Indole-3-acetic acid (IAA), naphthylacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D)) at a concentration of 5.5–9.5 mg/L in combination with 2.0 mg/L 6 benzylaminopurine (BA) to determine induction and proliferation of callus. The increasing value of callus fresh weight was used to assess the growth of the callus in treatments. The results showed that a steady increase in callus fresh weight and inulin content in callus cells was obtained when they were cultured on MS medium supplemented with a combination of 2.0 mg/L BA with 7.5 mg/L IAA in lighting conditions with radiation equalized by the flux density of photosynthetic photons and ratios of radiation levels in the region of FR—far red > R—red. Increasing demand for organic inulin sources in production practice can be met by our finding.

The ginger family member purple amomum (Amomum longiligulare T.L. Wu) is an important medicinal plant in Vietnam. Although there have been studies on the chemical composition of essential oils and extracts of purple amomum, as well as their antibacterial, antifungal, activating macrophages, and immune enhancement effects, there is still a lack of evaluation of the phytotoxicity of this plant. In this study, the total content of phenolic (TPC) and flavonoid (TFC) in extracts of leaf, seed, pseudo-stem, rhizome, and root from purple amomum and the phytotoxic effect of these extracts against five test plant species, including four dicotyledonous: camelina (Camelina sativa Crantz), quinoa (Chenopodium quinoa Willd.), cabbage (Brassica oleracea var. capitata L.), tomato (Solanum lycopersicum L. cv. Dubrava), and one monocotyledonous: onion (Allium cepa L. cv. Stuttgarter risen), were investigated. Results showed that the seed and leaf extracts had higher total phenolic and flavonoid contents than the other two extracts (highest TPC value: 4.30 ± 0.03 mg GAE/mg dry weight of seed powder; highest TFC value: 1.32 ± 0.07 mg QE/mg dry weight of leaf powder). Furthermore, it was observed that the extracts of purple amomum inhibited seed germination and the growth of seedlings of all test plant species with different inhibition values. The general trend in all treatments showed that, when increasing the concentration of extracts from 0.10–0.20 mg/mL, the ability to inhibit seed germination, hypocotyl length, radicle length, fresh weight, and dry weight increased. Seed extract at a concentration of 0.20 mg/mL in most treatments showed the highest percentage inhibition of seed germination and growth of seedlings of the tested species. Onion was the most sensitive to purple amomum extracts among the five species tested. Based on these results, we conclude that extracts of different parts of the purple amomum exhibited phytotoxicity for the tested species. Further evaluation of the phytotoxic potential of the extracts on weed species and under field conditions is also recommended for the purpose of developing bio-herbicides for future weed management that are less toxic to the environment and human health.

Ho et al. proposed to exclude Stenogyne section from the genus Gentiana and classifying it as a distinct genus (Metagentiana). Fourteen species of this genus have been recorded and distributed in China, Myanmar and Thailand. This is the first time there has been a confirmed genus Metagentiana distributed in Vietnam. This genus has two species: Metagentiana rhodantha and Metagentiana primuliflora, which are proposed in Vietnam. Particularly, Metagentiana rhodantha, which had only been known from China, was reported in Vietnam. A detailed description along with their distribution, habitat, ecology, illustrations, and photos has been provided to aid species identification. The key to identify all taxa of the genus has been constructed