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Application of CLUMondo Model in Forecasting Land use Changes in Van Yen district, Yen Bai Province

Pham Duy Khanh, Vu Thanh Bien, Dao Xuan Thu, Nguyen Luu Ly, Ngo Thanh Son, Bui Le Vinh

Received: 25-10-2022 / Accepted: 18-04-2023
This study applied the CLUMondo model to simulate land changes for land use planning in Van Yen district, Yen Bai province under two scenarios: Scenario 1- land use demand in the past and Scenario 2- based on local land use orientation. The simulation principle of the model was based on the interaction between the influencing factors and land use types through logistic regression. The simulation accuracy of the model for the 2020 overlay map was evaluated by the Kappa coefficient of 0.88. The simulation results show that by 2030, in scenario 1, construction land fluctuates the most (increase by 9.82%), while forest land and agricultural land decrease to 83.25% and 1.77%, respectively. In scenario 2, the forest and agricultural land also tend to decrease, but less than in scenario 1. The most obvious difference between the two scenarios is that the area of construction land increases sharply in scenario 1 compared to scenario 2, and the bare land with shrubs increases in scenario 1 but decreases in scenario 2.
Adventitious Root Induction and Culture of Morinda officinalis How

Ninh Thi Thao, Nguyen Thi Phuong Thao, Nguyen Thi Thuy Linh, Nguyen Tuan Minh, Nguyen Quynh Chi, Tran Thi Anh Dao

Received: 11-05-2015 / Accepted: 28-06-2016
This paper presents the results on induction of adventitious roots of Morinda officinalis How and effect of some chemical factors on adventitious root growth. Stem and leaf explants were cultured on MS medium supplemented with -NAA, IAA and IBA at five concentrations (0.1-1.0 mg/l) to regenerate adventitious roots. Among the auxins, -NAA showed the highest adventitious root formation for stem explants, followed by IAA and IBA. The maximum percentage of stem explants induced root (100%) was obtained when cultured on MS medium supplemented with 0.75 mg/l -NAA after 4 weeks of culture. However, adventitious root induction was not observed in leaf explants cultured on MS + 0.75 mg/l -NAA. Of the two tested media, B5 medium sustained better root growth than MS medium. -NAA, IAA and IBA had positive effect on adventititous root growth and development. After 12 weeks, the highest adventitious root biomass (1.264 g) was obtained on B5 medium supplemented with 1.0 mg/l -NAA.
Methods of Spawning Induction In Gastropoda -A Review

Le Van Binh, Ngo Thi Thu Thao

Received: 13-12-2021 / Accepted: 27-05-2022
The goal of this article was to summarize some of the mechanisms of spawning induction in gastropoda in the marine and freshwater environment. Nutritional and environmental factors (lighting, temperature, and the tidal cycle-for marine species) affected the changes of the endocrine system in gastropoda. The changes in environmental conditions also affected the change of reproductive structure. Illumination cycle, temperature, change of water source, and hydrogen-peroxide solution (H2O2) affected the central nervous system, stimulating the egg-laying process of most gastropoda. For marine gastropods, using H2O2solution and ultraviolet or heat shock all gave good spawning efficiency. However, other methods such as changing the water depth or combined with rain spraying, pituitary glandinjections, and tentacle cutting were more effective in spawning induction for freshwater gastropoda.
Utilization of Natural Haploid Inducer, UH400, for Hybrid Maize Breeding

Pham Quang Tuan, Dòng Huy Giói, Nguyen Viet Long, Vu Van Liet, Nguyen Thi Nguyet Anh, Nguyen Van Ha, Doan Thi Yen, Nguyen Trung Duc

Received: 25-07-2016 / Accepted: 20-11-2016
Adaptability and haploid inducing ability of UH400 were evaluated in 4 cropping seasons during 2014 and 2015 at Gialam, Hanoi, Vietnam. Twenty yellow dent maize hybrids were crossed with UH400 and the F1 seeds were evaluated for haploid induction rate using anthocyanin color marker. Ploidy doubling was done by colchicine treatment at 0.06% for 8 hours to develop double haploid (DH) lines. DH lines were evaluated for growth and yield in 2015 spring cropping season and ploidy level determined in spring 2016. The studies showed that UH400 can be grown in fall-winter and spring cropping seasons in the North of Vietnam, while seed multiplication and line maintenance be done in spring. UH400 can be used for haploid induction on yellow dent maize hybrids with induction rate of 7.05%. DH lines developed in this study had poor survival rate (14.4%). The use of SSR marker phi065 to identify haploid seeds from six crosses with UH400 showed that five crosses (M8, M12, M19, M21 and M22 crossed to UH400) are haploid.
Study on Maturation Broodstock Culture and Artificial Reproduction of Yellowcheek (Elopichthys bambusaRichardson, 1844)

Nguyen Hai Son, Vo Van Binh, Dang Thi Lua

Received: 25-03-2021 / Accepted: 22-06-2021
The study on maturation broodstock culture and artificial reproduction of yellowcheek (Elopichthys bambusaRichardson, 1844) was conducted from 12/2019 - 8/2020 at the National Freshwater Broodstocks Center. The aim of this study was to identify suitable foods for culturing maturation broodstocks, optimum hormone dose and appropriate incubation equipment for producing yellowcheek seeds. The results indicated that the use of chopped silver carp as food for culturing yellowcheek broodstock in the pond provided the higher maturation rate of broodstocks than using a food formulation consisting of 50% silver carp + 50% pellet feed and using 100% mixed pellet fish with 40% protein. Hormone dose of 60µg LRH-A + 10mg DOM/kg female gave the highest ovulation rate with the effect of hormones from 5-6 hours at 27-31C. Using Weiss incubators (Cycle tank) for incubating eggs showed a higher hatching rate (84.4%) and survival rate after 13 days (56.7%) in comparison with trays (68.7% hatching rate, survival rate 45.7%).
Evaluation of Effects of Herbal Product PremixHad and Doxycycline on Feed Conversion Ratio and Small Intestinal Villus Measurements in Swiss albino Mice

Hoang Trung Hung, Vu Van Cuong, Nguyen Thi Minh Phuong, Do Van Hieu, Phuong Thien Thuong, Nguyen Duc Hung, Nguyen Ba Tiep

Received: 28-03-2023 / Accepted: 04-08-2023
Thí study aims to evaluate the effectiveness of herbal product PremixHad and doxycycline on feed intakes, feed conversion ratios and villus measurements of small intestine in Swiss albino mice via growth parameters and micro-morphological measurements. The results showed that PremixHad supplement in feed with concentrations of 1.25%; 2.5%; 5.0% and doxycycline (2g per liter of drinking water) were safe for the mice. Supplement concentation at 1.25% improved BW gain. PH and doxycycline increased feed efficiency via the decrease of FCR. PH showed good effects on height, width and height/width ratios of duodenal and jejunal villi but no effect on ileal villus sizes. Meanwhile, doxycycline decreased these parameters in the mouse illeum. It can be said that PH is safe with positive effects on the intestinal health of Swiss albino mice and should be tested in livestock animals to confirm the effectiveness.
Otolith Morphology Description of some Reef Fishesin the Coastal Areas of Cat Ba and Tho Chu Islands

Vu Quyet Thanh, Tran Van Dat, Phung Van Gioi, Tran Van Huong, Tran Cong Thinh

Received: 03-11-2021 / Accepted: 01-03-2022
The study focused on describing the otolith morphology of 14 fish species in the territorial sea areas of Cat Ba (Hai Phong) and Tho Chu (Kien Giang) islands. Using the descriptive method of the authors Harkonen, Campana, Svetocheva; Brodeur. The results showed that otoliths had various shapes and structures such as bow-shaped ellipse (Sargocentron rubrum…), leaf-shaped (Hemiramphus sp…), disc-shaped (Plotosus lineatus…); rostrum,antirostrum(Pentapodus setosus - long;Sargocentron rubrum - unclear), ostium, cauda - shallow, deep(Selaroides leptolepis -shallow; Crenimugil pedaraki- deep…). The otolith size measured using the software Olympus cellSens Standard 2.2 and the ShapeR package in the R programming language.The results indicated thatthere existed differences in otolith size between species (F >> 1; P<0,05).The average size OL, OW, P of Longfin mullet (Crenimugil pedaraki) was highest (OL = 8.03 ± 0.12; OW = 4.07 ± 0.08; P = 24.38 ± 0.15) and the size of Decorated ponyfish(Nuchequula gerreoides)wassmallest (OL = 0.75 ± 0.01; OW = 0.37 ± 0.02; P = 1.35 ± 0.112). The ratio OL/OW has the highest value for tropical sand goby (Acentrogobius caninus)(0,84) and the lowest value for shrimp scad (Alepes djedaba)(0.34).This ratio was different between species (F = 169.1; P <0.05).
Morphological Relationshipsbetween Clutch and Evaluation ofFecundity Black Apple Snail (Pila polita)

Le Van Binh, Ngo Thi Thu Thao

Received: 19-10-2019 / Accepted: 19-01-2020
Morphological relationshipsbetween clutch and fecundity of black apple snail (Pila polita) was studied on the 349 clutches (in Dong Thap, Hau Giang and Vinh Long provinces) with the number of: 121, 113 and 115 clutches, respectively, which were collected from May to August 2017.At the same time, four-repeated experiments on rearing of 3 height groups snails (48.0-50.0 mm; 52.0-54.0 mm and 56.0-58.0 mm) were done to determine fecundity. The rearing was carried out in foam containers (60 × 45 × 40 cm) with a density of1 pair of broodstock snail/tank. Results of the study showed that the morphological relationship between clutch weight with clutch dimensions, the length of the clutch with the size criteria is quite tight (R2= 0.6-0.8). The fecundity of black apple snail is 208 eggs/snail, relative fecundity is 6208 eggs/kg snails. Spawning activity of black apple snail is mainly at night, starting from 20 pm to 4 am and lasts up to 8-12 hours. Black apple snail female is able to re-reproduce for the first time (42.7%).However, the ratio of the second batch is very low (8.3%), the average time for re-spawning of black apple snail is 42.2 days.
Study on Spawning Stimulation of Black Apple Snails (Pila polita)

Le Van Binh

Received: 25-06-2019 / Accepted: 13-08-2019
This study was carried out to examine the effects of different stimulation methods on spawning of the black apple snails, Pila polita. The experiments were arranged in 1 m3 tanks (1×1×1 m) at density of 15 pairs of broodstock snail/tankwhere water column at the beginning was 40 cm high. Experiment 1was done with 4 different water exchanging regimes: 1) Discard 25% water (D25); 2) Discard 50% water (D50); 3) Discard 75% water (D75) and 4) Discard 100% water (D100). Results showed that the highest spawning rate occurred at D75 (60.6%), following by the D50 (58.3%) and these were significantly different from D25 or D100 (P <0.05). The broodstock snails at D75 released highest egg clutches and reproductive efficiency (9.08 clutch/m2; 3.03 clutch/day/m2) and statistically significant different from D25 and D100 (P<0.05). Experiment 2 was implemented in the same condition as the early one (started with 40 cm of water level in the experiemental tanks) but with 4 different spawning stimulation methods: 1) Adding 25% water (A25); 2) Adding 50% water (A50); 3) Adding 75% water (A75) and 4) Addiing 100% water (A100). The spawning rate in A50 (82.2%) was significantly higher (P <0.05) than that inA25 (66.7%) and A100 (64.4%). The numbers of released egg clutches and reproductive efficiency of the snails in A50 (12.3 clutch/m2; 4.11 clutch/day/m2) were significantly higher than those (P<0.05) from A25 (10.1 clutch/ m2; 3.33 clutch/day/m2) or A100 (9.7 clutch/m2; 3.22 clutch/day/m2). The research results show that the spawning stimulation by renewing 75% of water or adding 50% of water volume gave the higher reproductive efficiency than other methods.
Scenarios for Reducing Enteric Methane Emission from Small Scale Dairy Production Farms in BaVi, HaNoi

Le Dinh Phung, Le Duc Ngoan

Received: 31-03-2015 / Accepted: 02-06-2015
An investigation was conducted to study the impact of alternative feeding practices on productivity and cattle enteric methane emissions of smallholder dairy systems in Ba Vi, Ha Noi. The study included two phases. During the first phase, data was collected in 30 farms in Ba Vi, Ha Noi through a semi-structured questionnaire. Average farm size (Mean± SD) was 0.85 ± 0.50 ha (15% crop area) and ~ 9 heads of pure and crossbred Holstein Friesian cattle. Herd structure consisted of 11, 25, 17 and 47% of calves, heifers, dry and lactating cows, respectively. Annual milk yield/farm was 28,655 ± 16,035 L (~US$ 20,059). Daily milk yield/cow was 14.1 ± 2.9 L. Using the feed supplied in each farm, the Ruminant model estimated yearly cattle enteric methane emission of 590 ± 359 kg per farm, 14.8 ± 8.99 tones CO2eq/farm and 0.52 ± 0.14 kg CO2 eq/L/milk. In the second phase, data was computed using a fixed representative farm to estimate responses to different feeding practices. Results showed that in comparison with Nepier grass (Pennissetum purpureum) and Guinea (Panicum maximum) or maize (Zea mays; 50% DM of the diet), the use of Ruzzi (Brachiaria ruziziensis) grass improved milk yield up to 14% and reduced enteric methane efficiency up to 9.4%. Potential increase of milk yield (5.3%) and decreased enteric methane efficiency up to 3.6% were predicted when maize silage substituted 50% of the elephant grass.
Effect of Seeds on Different Umbel Positions to Growth, Development and Yield of Angelica dahuricaBenth. Et Hook. F. at Gia Lam Ha Noi

Ninh Thi Phip, Nguyen Huu That

Received: 06-08-2012 / Accepted: 15-09-2012
“Bach Chi” is a medicinal plant and an essential constituent in traditional medicine. The plant has abundant flowers and fruits distributed on the different umbels. Time of flowering, number of umbels, umbel size, seed size and seed yields are different on each umbel position. Seed yield is highest on the secondary umbels (149.5 gr), but lowest on the central umbels. The aims of this paper are to determine whether the seed quality varies with umbel position and any effect of umbel position on growth, development and yield of Angelica dahurica Benth. Et Hook. F (Apiaceae) exists. Seeds were collected at five umbel types (center, primary, secondary, teriary and posterior umbels uppermost). Characteristics of individual umbels (duration of flowering, size) and plants (reproductivity, age, height, basal diameter) were recorded. The results showed that plants obtained from fruits on primary and secondary umbels grew much better (i.e. plant height, root diameter and yield) than those in collected from other umbels. The highest of root yield (3.16 ton/ha) and grade I percentage of roots (94.32%) were obtained from plants derived from seeds harvested on secondary umbels. The fruits on the primary, secondary and tertiary umbels are recommended for high quality of seeds to produce high quality of Bach Chi roots.
In vitro Propagation of Morinda officinalisHow

Hoang Thi The, Nguyen Thi Phuong Thao, Ninh Thi Thao, Nguyen Thi Thuy

Received: 15-04-2013 / Accepted: 18-06-2013
Thestudy was conducted to establish the procedure for in vitropropagation of Morinda officianalisHow using stem segments. The stem segments were initiate cultured on MS medium containing 0,25 mg/l Kinetinand 1,0 mg/l BA, on which 96,6 % of explants induced shoots after 30 days of culture. The highest shoot multiplication rate (10,13 times) was obtained on MS medium supplemented with 3,0 mg/l BA; 0,2 mg/l IBA and 10,0 mg/l Riboflavin after 45 days of culture. Root induction medium was ½ MS containing 0,2 mg/l IBA and 0,4 g/l activated charcoal.The average rooting frequency was 100 % with a mean of 3.5 roots/shoot within 30 days. In vitroplantlets after 35-days period of rooting were the most appropriateforsuccessfulacclimatization in greenhouse. The highest frequency of acclimatized plantletswas 96,2 %inthe organic substrate containing 50 % of coconut fiber and 50 % of mushroom-production waste materials, the plantlets showed good growth and development.
Effect of Time Destroying the Growing Point on Propagation Efficiency of Pineapple (Ananas comosus) cv. MD2

Le Vinh Hung, Nguyen Thi Ngoc Diem

Received: 25-03-2024 / Accepted: 21-06-2024 / Published: 25-07-2024
The pineapple variety MD2 has low, prolonged and ununiform shoot production under natural conditions. Therefore, it is very necessary to process buds simultaneously by destroying the growth tip to improve propagation efficiency for production. In this study, shoot tip/growing point was destroyed at time points (3.5, 4.5, 5.5, 6.5, 7.5 and 8.5 months after planting) and shoots of different sizes (4cm and 3 true leaves; 6cm and 4 true leaves; 8cm and 5 true leaves; 10cm and 6 true leaves; 12cm and ≥ 6 true leaves) were recorded. Research results show that mother plants shoots of 8.5 months after planting were treated and suckerss with a height of 4cm and 3 true leaves yielded 48.87 suckers/year. However, the plants were treated 7.5 months after planting combined yielded suckers with 8cm and 5 true leaves. The treatment time points and the size of the buds collected did not affect the sucker formation time ranging from 40.90 to 45.76 days and the survival rate after transplanting from 84.56 to 99.87%.
DOI: https://doi.org/10.1234/1fxw2a37
Factors Related to Quantity And Quality of OocytesCollectedfromAbattoir Bovine Ovaries

Nguyen Van Thanh, Vu Minh Lam, Nguyen Duc Truong, Nguyen Hoai Nam, Do Thi Kim Lanh

Received: 17-04-2023 / Accepted: 29-08-2023
The study was conducted to evaluate the influence of breed, body condition score (BCS- Body condition scores), ovary volume and the largest follicle size on some parameters related to the number and quality of bovine oocytes (classify as A, B level were good oocytes and C, D level were not good oocytes). The results showed that there was no significant difference on the average number of follicles on the ovary surface, the number of oocytes obtained, and the ovary volume between the cattle breeds but the average mass of follicles/ovary. Specifically, the average volume of follicles/ovary in Yellow cattles (6.11g) was higher than in Dairy cattles (2.66g, P <0.05). BCS did not affect the mean follicle size, mass, and the total number of follicle obtained. Ovarian mass, the largest follicle size had an influence on the total number of follicles and the number of oocytes obtained. Ovaries with a mass of 5-10g having the average total number of follicles, the total number of A, B and C, D follicles accounted for the highest number (11.21 follicles; 3.9 and 6.51 oocytes). Similarly, the number of A-B and C-D oocytes obtained from the ovary with the largest follicle size ranged 3-7mm were 4.06 and 7.09, respectively (P <0.005).
Simulation ofChanges inAgricultural Land use in the Coastal Area of Nam Dinh Province using the CLUMondo Model

Nguyen Thi Phuong Hoa, Ngo The An, Le Thi Giang

Received: 04-06-2021 / Accepted: 06-07-2021
This study applied the CLUMondo model to predict agricultural land-use changes to 2030 in the coastal area of Nam Dinh province. The predictions weredonebased on the correlations between the probability of changesrelated to each land use typeand its location suitability factors. Model outputs were validated by ROC statistic and Kappa coefficient.Results showedthatchanges inagricultural land use in 2030followed scenario 1 (baseline) with a decrease in rice areabut increase in the aquaculture area. The trend was similar in scenario 2 (as the land use planning) but the rice area was more decreased. In addition, in both scenarios, there was an increase in annual and perennial crops. Under the assumption of scenario 2, freshwater aquaculture tendedto continue expanding to paddies, while a portion of brackish water aquaculture wasconverted to forest land. Therefore, when implementing land use planning, it is necessary to prepare solutions for trading-off between staple food and aquaculture to ensure food security and sustainable development for local communities.
Effects of Fruit Pruning and Wrapping Materials on Fruit Size and Quality of Jujube Fruit (Ziziphusmauritiana Lamk.)Variety 05

Nguyen Thi Phuong, Nguyen Hoang Viet, Vu Thanh Hai, Nguyen Thi Thu Huong, Nguyen Thi Hai Xuan

Received: 17-12-2019 / Accepted: 03-02-2020
The study aimed to evaluate the effects of fruit thinning and fruit wrapping materials on fruit size, fruit quality traits and fruit loss rate due to insects and diseases infecting jujube fruit variety 05. Two independent experiments were conducted on 3-year- old jujube plants, which was designed as a randomized complete block design with four treatments and three replications per treatment. Fruit thinning treatments included removing 10%, 20%, 30% and zero % (control) of the total number of fruits per plant. Fruit wrapping material treatments included nylon bag, sponge bag, oil bag and no-wrapping (control). The results showed that fruit thinning increased fruit size, fruit weight and total soluble solids content (TSS), and decreased total acid content (TA) of the fruit. Out of fruit thinning treatments, thinning 30% of the total fruit number per plant resulted in the highest fruit weight (99.36 g) and TSS (17.2oBrix), and the lowest TA (0.180%), at the same time, the treatment reduced actual fruit yield (37.8 kg/plant) and increased the net revenue (772.000 Vietnam dong/kg). Wrapping fruits by nylon bag and sponge bag increased fruit weight of 25.3% and 17.7% compared to the control treatment, respectively. The sponge bag returned the second rank of fruit yield (44.7 kg/plant) and net revenue (1,001,000 Vietnam dong/plant) and did not affect TSS value (17.02%). The nilon bag decreased TSS (15.69%) but returned the highest fruit yield (47.8 kg/plant) and net revenue (1.258.000 Vietnam dong/plant). Therefore, the application of the wrapping materials into commercial production of jujube, nilon and sponge bags, is potentially economical.
Prediction ofWater Requirementsfor Land Use Types in Srepok River Basinin the Context of Climate Change

Nguyen Thi Ngoc Quyen

Received: 30-11-2018 / Accepted: 11-04-2019
In agricultural production, irrigation water is at the forefront, especially in the context of climate change. The objective of this study wasto predictthe irrigation waterrequirementsfor the major land use types in the Srepok basin and to propose agricultural land-use planning to support decision makers in integrated river basin management towards sustainable development. The modeling approach under thesupport ofCROPWAT 8.0and assessment of natural land adaptation process were applied in the study. Irrigation demand for coffee, pepper, cashew, rubber, tea, rice, maize and cassava were calculated in 2015with highest value of 7.746 m3.ha-1.crop-1forwinter-spring rice. Theirrigation water wasforecast for the future (2045) with decreasing trend in three scenarios (11.7% for low scenario, 18.59% for average scenario and 4.25% in the high scenario) compared to the presentperiod. Furthermore, three maps for agricultural land-use thatdefine suitable areasand spatial allocation of land use plans, were proposed with climatechange scenarios as a response solution.
Effect of Light Emiting Diode Lighting and Elicitors on Biomass and Antioxidant Activity of Solanum hainaneseCalluses

Nguyen Thi Ly Anh, Nguyen Thi Thanh Phuong, Doan Ngoc Han, Nguyen Van Trinh

Received: 14-08-2018 / Accepted: 18-03-2019
Solanum hainanense,a valuablemedicinal herbis used for detoxifying and protecting the liver. This plant accumulates different alkaloids and glycol-alkaloids that could inactivate Hepatitis B virus, acting as antioxidant and preventing cirrhosis effectively. Callus culture is a potential method to producesafe and high quality medical materials. Light spectrum and elicitors (yeast extract and salicylic acid) hadsignificantly positive effect on the increase of biomass and antioxidant activity of Solanum hainanensecallus culture on gel medium. LED lighting with a 30/70% of Blue/Red spectrum increased the dry biomass of callusesby 2.46 times compared with lighting by T8 fluorescence lamps. When adding 100 M salicylic acid or 3g/L yeast extract to the culture medium, the dry biomass of the calluseswas 2.43 or 3.04 times higher than the control, respectively. In addition, elicitors increased the antioxidant activity of the callus extract from 1.26 to 1.49 times of that of the control callus extract and increased from 2.31 to 2.73 times compared tothe two-year-old natural herbalextracts. These results could serve as the basisfor the development of in vitroculture systemfor improving the biomass and antioxidant activity of Solanum hainanense callusesand for expanding the research to other medicinal plants.
Population Dynamics of Javaen Barb(Systomus rubripinnisValenciennes, 1842) along Hau River, Mekong Delta of Vietnam

Au Van Hoa, Tran Van Viet

Received: 10-05-2018 / Accepted: 05-10-2018
A study on population dynamics of Javaen barb (Systomus rubripinnis)was carried out from January toDecember, 2016 along Hau River in An Giang and Can Tho provinces. Trap fence nets and gill nets were used for monthly fish catch sampling. Fishes were counted and measured for body weight (g) and length (cm) to monitor the temporal and spatial fluctuation on quantity and size. Results showed that the growth rate was high (K = 0.5/year); the survival rate after hatching to fishing size in the wild was low (6.2%); the total mortality was 2.8/year, and the fish was mostly caught at 8-11 cm in body length. The fish of smaller sizes was not affected by fishing gears and larger sizes were rarely found in the wild. The total length of fish could reach 20.5 cm. The breeding of this species occurred the whole year round with the peak in rainy and flooding seasons. Phytoplankton and detritus were the main food of this species. Larger fish was found more abundant upstream.
The Research Result of Development Stages of Scaly giant clam’s Gonad (Tridacna squamosaLamarck, 1819) by Histology Method

Do Anh Duy, Nguyen Quang Hung, Tran Van Huong, Dong Thi Dung, Nguyen Thi Thu Ha

Received: 07-06-2012 / Accepted: 18-08-2012
The report presents research results of the development stages of scaly giant clam’s (Tridacna squamosa Lamarck, 1819) gonad in 8 Vietnam islands from 2010 to 2011. The scaly giant clam samples were collected in coral reef (from March to July) and from the divers in Nha Trang Bay and adjacent areas (in months). Histological method was employed to analyze the development stages of gonad. The research results showed that scaly giant clam is a hermaphroditic species. The individuals with the shell length under 18-20cm exhibit maleness character while in individuals with the shell length above 18-20cm the gonad differentiate into spermary and ovary. The development of scaly giant clam’s gonad experiences 6 stages (from stage 0 to stage V). Among them, stage III, the largest size are in the eggs and sperms. The egg cells are round or elliptic in shape and arranged with each other in the ovaries. Diameter of the eggs is measured at 90-110μm. The spermary contains a large quantity of mature sperms; the sperm head size is about 3μm. The research results are useful for identifying each stage of the development of scaly giant clam’s gonad and breeding season through the level of the gonad maturity.
Age and Size Effects on Spawning Performance of pathegen-free Broodstock of White Leg Shrimp (Litopenaeus vannamei)

Vu Van Sang, Vu Van In, Tran The Muu

Received: 11-07-2013 / Accepted: 08-11-2013
Experiments on the effects of broodstock size at 35-39g; 40-44g; 45-49g; 50-55g and 60g (experiment 1) and age ranging from 7; 8; 9; 10 and 11 months old (experiment 2) to reproductive performance of white leg shrimp (Litopenaeus vannamei) broodstocks free of pathogen were conducted in in-door composite tanks of 14m2(for broodstock intensive rearing) and 1m3(for spawning and larval rearing) under biosecurity conditionattemperature of 28-30oC, and salinity of 28-30‰. Shrimpswere fed 4 times per day with blood worm (50%) and fresh squid (50%).Water was renewed 100% daily. For breedinginduction, eye-stalk ablation was applied to the female shrimpsafter 30 days intensive rearing. Female shrimps of 45g or bigger showed significantly better reproductive performance than smaller ones (P<0.05), reaching mature rate of 89.0%, mating and spawning rate of 86.0%, fecundityof 175,200 eggs/dam/spawn, and nauplii production per spawn of 88,700 nauplii. On the other hand, shrimpsat age of 8 -12 months have considerably higher spawning performancecompared to age group of 7 months (P<0.05) with mature rate of 86.7%, mating and spawning rate of 84.1%, fecundity of 207,400 eggs/dam/spawn, production of nauplii per spawn of 127,500 nauplii.
RestoringShaft of Stone Sawing Machine Using Build- Up Welding Method

Tong Ngoc Tuan, Le Van Tuan

Received: 04-04-2015 / Accepted: 12-07-2016
The shaft of stone sawing machine in working process often occurs faulty. Common form of fault is the wornnessover limited dimension at the center shaft. One of the methods that brings high efficiency andmeeting in time for manufacturing might berestoration of theshaft using build- up welding methodtoachieve the desired dimension. Based on theoreticalresearch onwelding technology, shielded metal arc welding for building- up weldwas selected. This is one of the methods that can be easily usedwith availableequipments. Equipmentselection, welding condition, manufacturing process, manufacturingcondition, andqualityevaluation were done to ensuregood operation after machine assemblage. Different equipmentswere used to test the shaft forroughnessandhardnessand the shaft quality was checked by operation trials. Fivesamples wereselected forrestoration and quality evaluation. Relying on all evaluating methods, all shafts have good quality.
Assessment of the Growth and Development of Daylily(Hemerocallissp.) Genotypes in Gia Lam, Hanoi

Pham Thi Minh Phuong, Pham Thi Bich Phuong, Nguyen Anh Duc, Nguyen Xuan Truong

Received: 05-06-2022 / Accepted: 27-09-2022
This study aimed to select new desirable genetic materials in terms of plant growth and shape, size and color of flowers for decorative daylily development program in Vietnam. Sixteen hybrid lines and three cultivars were evaluated. Each genotype was planted with 15 clusters and 2 stems for each cluster. Plant height, number of leaves per stem, flower scape size, number of buds per plant, flower sizewere recorded. All lines/cultivars showed good growth and development in Hanoi’s climate condition. The plant height ranged from 46cm (183-9) to 116.3cm (133-13), scape height was from 38.7cm (193-9) to 110cm (133-5), and flower diameter was from 12.5cm (NB2) to 18.5cm (133-13). Their flower color was grouped into three categories:red, yellow and orange with varried patterns on the flower petals. The flower scape durability last from 7 days (188-1) to 21 days (133-3), resulting in cluster durability ranging from 12 days (NB2) to 31 days (133-3). Based on the growth and development, 12 best lines/cultivars, 193-3, 183-4, 188-1, 133-3, 133-8, 133-10, 133-13, K15, K16, 133-12, NN03, and KC19 were selected.
Morphological and Anatomical Characteristics of some Accessions of Glinus oppositifolius(L.)

Vu Thi Hoai, Ninh Thi Phip, Nguyen Thi Nga

Received: 12-10-2021 / Accepted: 05-07-2022
A Randomized Complete Block Design (RCBD) study was performed for characterized on morphology and anatomy of 5 assessions of G. oppositifolius(RĐ1-RĐ5) collected in 5 provinces in Vietnam. The results showed that all assessions have similar morphological structures (roots, stems, leaves, flowers, fruits, seeds), and anatomical structures (roots, stems, leaves). But there hadsome different characteristics in adult stem color (RĐ1, RĐ2, RĐ4, RĐ5 are reddish-brown, RĐ3 is yellow-green); leaf color (RĐ3 was light green, RĐ5 was dark green, RĐ1, RĐ2, RĐ4 were green); RĐ3 assession hadthe highest values of root and leaf size (the root number was 14.60 roots/plant; the leaf length and leaf width were2.33 ± 0.02cm and 1.00 ± 0.06cm, respectively), RĐ5 assession hadthe smallest values of leaf size (the leaf length and leaf width were 1.80 ± 0.01cm and 0.51 ± 0.05cm, respectively). Anatomically, the size of the parenchyma in the stem, the libe bundle in the roots, the stem, and the main leaf veins of the RĐ3 assession hadthe largest sizes. Whereas, the RĐ5 hadthe highest value of leaf thickness (palisade mesophyll thickness was 277.8 ± 6.8µm and spongy mesophyll thickness was 198.9 ± 10.3µm).
Đặc tính liên quan đến tính thèm ăn của polypeptide kích hoạt cyclase adenylate tuyến yên ở vùng giữa bụng dưới đồi thông qua tăng biểu hiện peptide liên quan đến agouti ở chuột nhắt

Thanh Trung Nguyen, Yuki Kambe, Atsuro Miyata, Thanh Ha Nguyen Thi, Van Phai Dam

Received: 01-06-2020 / Accepted: 10-01-2022
PACAP được biểu hiện nhiều ở các nhân khác nhau ở vùng dưới đồi và có chức năng giúp kiểm soát sự thèm ăn. Gần đây, chúng tôi đã phát hiện ra neuropeptide PACAP làm tăng cảm giác thèm ăn ở chuột. Nhằm làm rõ hơn vai trò của tế bào thần kinh PACAP, trong nghiên cứu này, đã sử dụng phương pháp hóa sinh với thụ thể thiết kế được kích hoạt chọn lọc bằng hệ thống DREADDs và kiểm tra sự kết nối qua synap của các tế bào thần kinh bởi các vector biểu hiện synapsin. Kết quả chỉ ra việc kích hoạt hay ức chế có chọn lọc các tế bào thần kinh PACAP bởi DREADDs trong VMH, làm tăng hoặc giảm đáng kể lượng thức ăn thu nhận. Ngoài ra, nghiên cứu này chỉ ra sự kết nối giữa tế bào thần kinh PACAP trong VMH với tế bào thần kinh AgRP ở vùng Arc. Những kết quả này cho thấy tăng thu nhận thức ăn do gia tăng biểu hiện PACAP trong VMH thông qua điều chỉnh biểu hiện AgRP và ức chế PACAP hoặc AgRP là ứng dụng lâm sàng quan trọng trong giám sát béo phì.

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