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• Study on Stem Cutting Propagation of Gynostemma Pentaphyllum (Thunb.) Makino in Hoa Binh Province

  Ninh Thi Phip, Nguyen Phuong Mai, Nguyen Thi Thanh Hai, Nguyen Mai Thom

  Received: Oct 28, 2020 / Published: Aug 10, 2021

   Abstract PDF

  Gynostemma pentaphyllum (Thunb.) Makino is a medicinal plant distributed mostly in the mountainous areas of Vietnam. G. pentaphyllum contains more than 189 types of saponin which can be used for the treatment of various diseases. Currently, due to over-exploitation, this plant species is under threaten. Our research aimed to study a suitable method for plant propagation by stem cutting techniques to promote the growth and development of G. pentaphyllum. Six experiments were conducted to (i) evaluate the established seedling rates of different G. pentaphyllum varieties, and choose the best variety to (ii) evaluate the established seedling rate influenced by different factors, viz. stem cutting position, cutting season, growing in the selected substrates, stem cutting length, number of buds per stem, and application of α-NAA. The results showed that among five varieties, G2 which was collected in Mai Chau district disclosed the highest ability to shooting, the highest number of roots per stem cutting, the shortest nursery days, the highest shooting rate, and the highestestablished seedling rate. We also determined that using middle-aged plants for stem cuttings, at 15-20cm in length, with 2 nodes and grown in Spring and Winter cropping seasons, using growing substrates with a mixture of 50% of black sand and 50% of soil, and plus α-NAA 50ppm in 3-5min produced the highest explant rate. The established seedlingsat the time of explant were 15-20cm in height, containing 4-5 leaves and at least 9-10 roots per cutting, and were 30-32 days.

• The Dispersion of Total Suspended Solids in Seawater Following Submersion of Dredged Material in the Vung Ang Port

  Nguyen Thi Hong Ngoc, Tran Anh Quan

  Received: Feb 27, 2023 / Published: Dec 29, 2023

   Abstract PDF

  Dredging plays a crucial role in port management, but disposing dredged material in the ocean raises environmental concerns. In recent years, this practice has become more prevalent in Vietnam. This study examined the dispersion of total suspended solids (TSS) in seawater from the submersion of dredged material in Vung Ang Port, northern Vietnam, to evaluate the environmental impact. The study utilized MIKE modeling to simulate the dispersion of TSS during the 16 weeks following the submersion of dredged material into the sea. The model was validated with observed data and adjusted to accurately reproduce wave, water flow, and water level fields. The simulation showed that the propagation of TSS had a significant impact within a radius of 16-17km from the submersion location, with the most severe impact occurring within a radius of 2-3km. The TSS concentration is expected to exceed allowable limits, peaking after 4-5 weeks. Seawater occupation will reach maximums of 49.05ha and 140.66ha for depth increases above 0.5m and 0.1m. The submersion will negatively impact the environment. It is essential to regularly monitor TSS in affected areas during and after dredging to evaluate long-term effects and mitigation effectiveness. The significance of conducting additional research on the matter and the crucial insights offered by this study to pertinent management agencies for their decision-making processes are emphasized in the article. The study offers crucial insights for pertinent management agencies.

• A Practical and Efficient Method for the Micropropagation of Japanese Cherry (Prunus sp.)

  Nguyen Thi Thuy Linh, Pham Thi Ngoc, Ninh Thi Thao, Nguyen Thi Phuong Thao

  Received: Feb 15, 2019 / Published: Feb 16, 2019

   Abstract PDF

  This study was conducted to establish the procedure for in vitro propagation of Japanese cherry (Prunus sp.) to produce large quantity of plantlets and initial planting materials for climate adaptation research of this plant in Hanoi. Single nodal stems were used as the primary explants and initially produced shoots on MS medium supplemented with 1 mg L-1 BA. The highest shoot multiplication rate (9.57 times) was obtained on MS medium containing 1 mg L-1 BA and 0.25 mg L-1 a-NAA after 8 weeks of culture. 100% of the shoots produced roots with a mean of 10.10 roots per plant within 4 weeks on ½ MSM medium with 4 mg L-1 IBA. The survival rate of in vitro derived plantlets after a 6 to 7-week-period of rooting during acclimatization using a soil: coco peat: smoked rice husks (2:2:1, v/v/v) substrate was 100% and acclimatized plantlets showed good growth and development. This is the first report on a practical and efficient in vitro multiplication protocol for Japanese cherry in Vietnam, starting from shoot initiation to establishment of plants under greenhouse conditions.