Optimal condition for Propagation and Growing of Dendrobium thyrsiflorum

Dendrobium thyrsiflorum is a medicinal orchid that is being gradually destroyed due to over-exploitation. This research focuses on in vitro production of D. thyrsiflorum plantlet under optimal acclimatization conditions. The results of the study showed that the best medium for seed germination was MS basal medium (full-strength MS nutrient plus 100 ml L-1 coconut water; 7 g L-1 agar, 30 g L-1 sucrose, and 0.5 g L-1 active charcoal) supplemented with 60 g L-1 mashed sweet potatoes, which induces 97.8% of seed germination. The shoot was well developed in MS basal medium supplemented with 60 g L-1 mashed sweet potatoes and 0.4 mg L-1 6-Benzylaminopurine (BA) and, corpulent and green in shoot morphology. The shoot multiplication rate was greatest on MS basal medium supplemented with 0.4 mg L-1 BA and 0.4 mg L-1 Kinetin with 4.53 times, and the shoot height was reported at 3.45 cm after 8 weeks of subculture. Further, The shoot was 100% rooting, with an average of 4.51 roots/shoot and 5.34 cm per root in length when the shoot was implanted on MS basal medium plus 60 g L-1 mashed sweet potatoes and 0.75 g L-1 active charcoal. Especially, plantlets after transplanting to the orchid net house reached a 94.8% survival rate on tree fern after 24 weeks. Hence, the results of the study suggested a successful production of D. thyrsiflorum plantlet on the selected media compositions

The Politics of Economic Reforms in Vietnam: a case of State-Owned-Enterprise Equitization

Ph.DDOCTOR OF PHILOSOPH

EFFECT OF SPENT MUSHROOM SUBSTRATE ON THE GROWTH AND YIELD OF THREE CULTIVARS OF MUSKMELONS (Cucumis melo)

Muskmelons are currently grown in several areas of Vietnam for domestic and international consumer markets. The fruit grows well in greenhouses in soil or soilless substrate such as coconut peat. Researchers in Vietnam are investigating the growth of muskmelons in a range of organic by-products. In this study, spent mushroom substrate was recycled for use as an organic substrate and to evaluate the growth, quality, and yield of three muskmelon varieties including RZ F1, PN 128, and TL3 in greenhouses over three months. The substrate was incubated for one month before use and contained 45% spent mushroom substrate, 30% manure, 7.7% rice husks, 1.5% phosphorus, 0.2% commercial Trichoderma (Tribac), 0.1% rice bran, 15% sand, and 0.5% micronutrients and water. Following incubation, the substrate had optimal pH for the growth of muskmelon and the concentration of nutrients and beneficial microorganisms had increased significantly. The growth of RZ F1 and TL3 cultivars was significantly better than PN 128 in terms of growth, fruit quality, and yield. Specifically, RZ F1 and TL3 species took 78 days and 75 days to complete their life cycle produced 1.76 kg and 1.62 kg of fruit, had a pericarp thickness of 4.0 cm, and possessed 14.20o Brix and 14.88o Brix of soluble solid content, respectively. These findings suggest that agricultural by-products, such as spent mushroom substrate, could be a valuable resource for the culture of muskmelons in Vietnam

INVESTIGATING THE EXPERIENCES OF STUDENTS WITH DISABILITIES WITH E-LEARNING DURING THE COVID-19 PANDEMIC IN VIETNAMESE HIGHER EDUCATION

This study uses a mixed-methods approach to investigate the experiences of Vietnamese university students with disabilities (visual/mobility impairments) with e-learning as a consequence of emergency remote teaching during the COVID-19 pandemic. An analysis of the ideas of 20 surveyed students with disabilities at eight universities in Ho Chi Minh City and six students interviewed afterward shows that students can change their study habits to adapt to e-learning and to enjoy this model of learning. However, the participants revealed that they also want to experience face-to-face learning so that they can interact with their lecturers and peers more effectively and in more diverse ways, as well as assimilate lectures more easily. Furthermore, the research shows that various adjustments should be made by system designers, universities, and lecturers to make e-learning friendlier to disabled students. The recommended adjustments include designing easy-to-use learning tools and platforms, providing lecturers with the necessary tools and facilities to design lessons appropriate for all students, providing psychological and technical support for disabled students, choosing user-friendly learning applications and platforms, providing students with suitable learning resources, and modifying testing and assessment methods

Effects of hormone and fertilizers on early flower induction of Dendrobium anosmum hybrid seedlings under ex vitro condition

Early flowering of new orchids is important to save time for selecting valuable flowers and artificial induction of flowering is a critical consideration in the orchid production industry. In this study, a new Dendrobium anosmum hybrid was generated by cross-breeding between D. anosmum ‘Chau Nhu’ and D. anosmum ‘Di Linh’. The ancestors and hybrid seedlings from in-vitro culture were trained in the net house and their growth and flowering were evaluated under ex vivo conditions with specific fertilizers and hormones. The results suggest that the hybrid plants grew better than their parents in terms of stem height, stem diameter, and leaf number. Growth hormones were applied to stimulate early flowering in matured hybrids and it was discovered that ‘Keiki pro’, a commercial hormone product, produced the best results, with a flowering rate of 66.67% after two applications. Hybrid flowers varied in width from 36.36% (3.0-6.0 cm) to 63.64 % (more than 6.0 cm) from ancestral width in medium-sized and large-sized flowers, respectively. Also, the hybrid flower colours was mostly a combination of pink/violet (75C) and purple/pink (68A), which is different from their parents. Importantly, the dorsal sepal, petal colours, and shape of hybrid flowers varied significantly among individual hybrids, between hybrids and their progenitors. Some mutations in the lips and columns of the novel hybrid flowers were also visualized. Hence, the D. anosmum hybrid seedlings successfully induced flowers after a year of culture under optimal hormones and fertilizers conditions. The results can serve as a critical reference for the early flowering of the orchid seedlings

Assesment of antidermatophyte activity of oil from Curcuma longa L. in vitro

Curcuma longa L. is a rhizomatous herbaceous perennial plant, and its essential oil showed antifungal, antibacterial, antioxydant, antivenom, and antitumor effects. The antidermatophytes of oil from turmeric was demonstrated. This study was carried out in order to evaluate inhibition activity of oil from Vietnamese turmeric against two strains dermatophyte, Trychophytol mentargrohytes and Candida albicans. The oil from Vietnamese turmeric was obtained by hydrodistillation method and its chemical composition was determined by GC/MS. By comparing with authentic reference compounds in mass spectra library Nist 98.1 and Wiley 275.L, 13 compounds of oil from Vietnamese turmeric were identified. The received results showed that, the oil is rich in turmerones (about 44%), which has been recognized as major constituent attributing to antimicrobial activity. By disc diffusion method, the antifungal activity of the turmeric essential oil against T. mentargrophyte and C. albicans was demonstrated. The MICs of the turmeric oil for T. mentargrophytes và C. albicans were 0.5%. The minimal killing time for C. albicans was 60 minutes and for T. mentargrophyte was 90 minutes after treatment with the turmeric oil

Inflationary Implication of Gold Price in Vietnam

The sustained elevated gold price domestically, hovering persistently above the global market price, underscores the peculiar nature of the gold market in Vietnam and the resiliently strong demand for gold in the local market. In particular, the movements in the price of gold seem to lead a symmetrical trend in the headline inflation since the outbreak of the 2007 global financial crisis. The primary objective of this study is therefore to assess possible inflationary consequence of the gold price movements in Vietnam. Past studies demonstrate that if gold could be viewed as a financial asset, shifts in the gold price should be monitored as one of the determining factors of inflation. Yet, hardly any study has assessed potential inflationary implication of gold in Vietnam, especially during the recent years of volatile and double-digit inflation rates

SCREENING, IDENTIFICATION AND BIOACTIVE PROPERITES OF BACILLUS SPP. ISOLATED FROM SHRIMP PONDS OF QUANG TRI PROVINCE

Aquaculture is the farming of aquatic organisms by intervention in the rearing process to enhance production and private ownership of the stock being cultivated. However, the intensification of aquaculture practices requires cultivation at high densities, which has caused significant damage to the environment and , aquatic species are subjected to high-stress conditions, increasing the incidence of diseases and causing a decrease in productivity. This study was conducted to isolate bacteria from sediments of shrimp culture ponds based on antagonistic activity against shrimp pathogen, Vibrio parahaemolyticus, and production of exocellular enzymes, protease and amylase. Three potential strains were isolated and after analysis of 16S rRNA gene, the isolated starin were identified to Bacillus subtilis (isolate QTA12 with amylase activity), Bacillus megaterium (QTP1 with proteolytic activity ) and Bacillus subtilis (isolate with antivibrio activity DK1). These isolated strains may be considered for future using in shrimp culture ponds as a very promising measure for sustainable aquaculture

Inflationary Implication of Gold Price in Vietnam

The sustained elevated gold price domestically, hovering persistently above the global market price, underscores the peculiar nature of the gold market in Vietnam and the resiliently strong demand for gold in the local market. In particular, the movements in the price of gold seem to lead a symmetrical trend in the headline inflation since the outbreak of the 2007 global financial crisis. The primary objective of this study is therefore to assess possible inflationary consequence of the gold price movements in Vietnam. Past studies demonstrate that if gold could be viewed as a financial asset, shifts in the gold price should be monitored as one of the determining factors of inflation. Yet, hardly any study has assessed potential inflationary implication of gold in Vietnam, especially during the recent years of volatile and double-digit inflation rates