Effect of Red LEDs during Healing and Acclimatization Process on the Survival Rate and Quality of Grafted Tomato Seedlings

Ngoc-Thang Vu,Young-Shik Kim,Ho-min Kang,Il-Seop Kim 한국생물환경조절학회 2014 시설원예‧식물공장 Vol.23 No.1

본 연구는 토마토 플러그묘의 접목후, 순화과정에서 단기간 광조사 여부가 접목 활착율과 묘소질에 미치는 영향을 구명하기 위하여 실시 되었다. 공시 품종으로 ‘B-Blocking’, ‘Kanbarune’, ‘High-Power’의 3종류 대목 품종에 방울토마토 ‘Choice’ 품종을 각각 접목한 뒤, 활착실에서 10일간 적색LED 광조사구와 무처리 (대조구)로 나누어 접목 활착율과 묘소질을 조사하였다. 적색 LED 광조사구의 접목 활착율은 대목품종에 관계 없이 무처리구에 비해 높았다. 광조사구 접목 활착율은 세 품종 모두 90% 이상으로 품종간의 유의성이 없었으나, 무처리구의 접목 활착율은 35~72% 정도로 품종에 따른 차이가 매우 컸다. 활착기간 중 곰팡이병 이병율도 ‘Kanbarune’를 제외하고 광조사구가 무처리구에 비해 저하하는 경향을 보였으나, 품종간 유의차는 나타나지 않았다. 묘소질은 경경, 엽수, 엽록소 함량을 제외한 모든 생육지표에서 LED광 조사구가 우수한 결과를 나타내었으나, 처리에 따른 대목 품종간 유의차는 전반적으로 나타나지 않았다. 지하부 생육에서 평균 근경을 제외한 뿌리 표면적, 전근장, root tip수는 광조사구가 무처리구에 비해 모든 품종에서 우세하였다. This study was designed to determine the effect of red LEDs during healing and acclimatization process on the survival rate and quality of grafted tomato seedlings. Red LEDs and no light (darkness) were used for treating three rootstock cultivars, which are ‘B-Blocking’, ‘Kanbarune’, ‘High-power’ in healing room. Results showed that survival rates of grafted seedlings in red LEDs were higher than those in no light treatment. Significant variation on survival rates of rootstock cultivars was observed in no light treatment but there was not significant variation in red LEDs treatment. Light treatment also reduced the percentage of infected plants, except for the ‘Kanbarune’ cultivar. Seedling quality in red LEDs was better than that in no light treatment by improving growth parameters such as plant height, leaf length, leaf width, leaf area, fresh and dry weight of shoot and root. Light treatments and rootstock cultivars did not affect number of leaves, leaf chlorophyll value and T/R ratio of seedlings, but seedlings in red LEDs were significantly more compact than those in no light treatment. Moreover, the root morphology of seedlings such as total root surface area, total root length, and number of toot tips in red LEDs was also greater than that in no light treatment.

EFFECT OF NURSERY ENVIRONMENTAL CONDITION AND DIFFERENT CULTIVARS ON SURVIVAL RATE OF GRAFTED TOMATO SEEDLING

Ngoc-Thang Vu,,Zhi-Hao Xu,,Young-Shik Kim,,Ho-Min Kang,,Il-Soep Kim, International Society for Horticultural Science (I 2014 Acta Horticulturae Vol.1037 No.-

Enhanced Graft-take Ratio and Quality of Grafted Tomato Seedlings by Controlling Temperature and Humidity Conditions

Ngoc-Thang Vu,김일섭,장성호,서지호,김영식,강호민 (사) 한국생물환경조절학회 2013 시설원예‧식물공장 Vol.22 No.2

This study was conducted to enhance graft-take ratio and quality of grafted tomato seedlings by controllingtemperature and humidity during the healing and acclimatization processes. Three temperature levels (20℃,23℃, and 26℃) were carried out to determine optimum temperature on four rootstocks. In addition, twelve combinationsof three relative humidity levels (70%, 80%, and 90%) and four temperature levels (17℃, 20℃, 23℃, and26℃) were set up to evaluate the effect of relative humidity and temperature on the graft-take ratio of grafted seedlings. In the other hand, five relative humidity periods (H0, H1, H2, H3, and H4: 90% relative humidity for first 0, 1,2, 3 and 10 days and afterwards relative humidity was reduced to 70%, respectively) were examined effect of relativehumidity periods on the graft-take and quality of grafted seedlings. The higher graft-take ratios (84.0~87.4%)were showed at 23℃ compared to 20℃ and 26℃ in all rootstocks. Graft-take ratios decreased and number of diseasedplants increased at high temperature. The graft-take ratios increased with increasing relative humidity in alltemperature levels on the 3rd and 7th day after grafting. However, increasing relative humidity significantly increasedpercent of diseased plants. The graft-take ratio reduced at (26℃) and (17℃) temperature under all relative humidityconditions. The graft-take ratio increased with increasing period of 90% relative humidity. Maximum graft-takeratios were observed in H2 and H3 treatments. Graft-take ratio decreased with increasing 90% relative humidity for10 days (H4). Diseased plants had not been found in H0, H1, H2, and H3 treatments. Seedling quality was improvedthrough increasing fresh and dry weight of root, compactness, and root morphology of tomato seedlings in H2 andH3 treatments. Therefore, high relative humidity (90%) for first 2 or 3 days and afterwards reduced low relativehumidity (70%) at 23℃ condition during healing and acclimatization promoted the graft-take and quality of graftedtomato seedlings.

Influence of Short-term Light Irradiation under Pre-and Post Grafting Period on the Graft-take Ratio and Quality of Tomato Seedlings

Ngoc-Thang Vu,Si Hong Kim,Young-Shik Kim,Il Seop Kim 한국원예학회 2013 한국원예학회 학술발표요지 Vol.2013 No.10

Improvement of Tomato Seedling Quality under Low Temperature by Application of Silicate Fertilizer

Ngoc-Thang Vu(넉탕부),Anh-Tuan Tran(안추안트란),Thi-Tuyet-Cham Le(띠투엣참리),Jong-Kuk Na(라종국),Si-Hong Kim(김시홍),Jong-Man Park(박종만),Dong-Cheol Jang(장동철),Il-Seop Kim(김일섭) (사)한국생물환경조절학회 2017 시설원예‧식물공장 Vol.26 No.3

규산 시비가 토마토 플러그 묘소질에 미치는 영향과 묘의 저온저장시 규산의 저온장해 경감효과를 검토하였다. ‘Rapito’품종을 공시하여 30일간 32구 규격의 플러그 트레이에서 육묘한 뒤, 여섯 개의 규산 처리농도구 (8, 16, 32, 64, 128 및 256mM)를 설계하여 20일 동안 주 2회 관주 처리한 뒤, 묘소질을 대조구와 비교하였다. 처리 농도는 16mM과 32mM 처리가 초장, 엽면적, 생체중, T/R율 및 근권부 발육 등 대부분의 생육지표에서 타 처리구에 비해 양호했으며, 특히 16mM의 농도에서 가장 좋은 묘소질을 보였으나, 64mM 이상의 고농도에서는 대조구에 비해 전반적으로 생육이 억제되는 경향을 보였다. 토마토 묘의 생리적 반응에서 엽온에서는 처리구별 차이가 나타나지 않았으나, 증산율은 32mM이상의 농도 처리구에서 기공확산 저항이 증가하면서 증산율이 감소되는 경향을 보였다. 또한, 처리 횟수에 따른 효과를 검토하기 위해 16mM농도의 규산을 20일 동안 6, 10, 20회 관주처리 한 결과, 대부분의 생육지표에서 처리 횟수간에는 큰 차이가 없었으나, 무처리구에 비해 묘소질이 향상되었으며, 특히 뿌리표면적, 근장, root tip수등 근권부의 생육이 현저히 증가하였다. 아울러 규산처리가 저온저장시 토마토 묘의 저온장해를 감소시키는 효과가 있음을 확인하였다. The object of this study was to improve tomato seedling quality in low temperature(below 7, 10℃ during night time or daily mean air temperature was 18℃) by application of silicate fertilizer. Six different silicate fertilizer concentrations (8, 16, 32, 64, 128, and 256mM) or water as the control were applied to tomato seedlings twice a week for 20 days. Positive effects were observed in the growth parameters of the seedlings treated with 16 and 32mM silicate fertilizer; the most effective concentration of silicate at which seedlings showed the best performance was 16mM. However, a high concentration of silicate (256mM) caused negative effects on the growth. The transpiration rate decreased alongside with the increase of silicate concentration up to 32mM, possibly due to the increased stomatal diffusive resistance. Silicate stimulated the growth and development of tomato seedlings, resulting in increased growth parameters and root morphology. However, no significant differences were observed among treatment numbers of soil-drenching wuth the silicate (6, 10, or 20 times with 16mM) for 20 days, suggesting that silicate treatment with 6 times may be sufficient to induce the silicate effects. The application of 16mM of silicate fertilizer reduced relative ion leakage and chilling injury during low temperature storage. In addition, the seedlings treated with silicate fertilizer recovered faster than those without silicate treatment after low temperature storage.

Influence of Short-term Irradiation during Pre- and Post-grafting Period on the Graft-take Ratio and Quality of Tomato Seedlings

Ngoc-Thang Vu,김영식,강호민,김일섭 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.1

The objective of this study was to evaluate influence of short-term irradiation during pre- and post-graftingperiod on the graft-take ratio and quality of tomato seedlings. Irradiation by six light qualities, darkness, white fluorescentlamps (WFL), red LED, far-red LED, blue LED, and natural light, were used to treat seedlings for 10 days beforegrafting. And Irradiation by five light qualities, darkness, WFL, red LED, far-red LED, and blue LED, were used totreat seedlings for 10 days after grafting, during healing and acclimatization periods. When short-term irradiation wasapplied before grafting, the graft-take ratios (27.8-66.7%) were considerably low in all light treatments as comparedwith natural light (96.7%). The graft-take ratio of red LED was not statically different with WFL treatment, buthigher than far-red and blue LED treatments. The lowest graft-take ratio (27.8%) was observed in darkness treatment. Changing light intensity before grafting was the cause of reduced graft-take ratios in this study. There was no significantdifference among natural light, WFL, and red LED treatments in growth parameters, except for leaf chlorophylllevel, leaf width, and fresh weight of root, but decreased in seedlings treated with far-red LED, blue LED, anddarkness. Graft-take ratios (68.5-100.0%) were enhanced when short-term irradiation was applied after grafting. Themaximum (100%) graft-take ratio was recorded in red LED treatment, but was not statistically different with the WFLtreatment. The lowest graft-take ratio was also observed in the darkness treatment. Plant growth responses to red LEDwere also similar with those to WFL after grafting. However, when short-term irradiation was applied after grafting,the lowest values of plant growth were observed in far-red LED treatment. The plant growth parameters were similarin seedlings treated with darkness and blue LED, but lower than red LED and WFL treatments. The root morphologywas improved in seedlings treated with red LED after grafting by increasing total root surface, total root length, andnumber of toot tips. Seedling quality increased at 35 days after transplanting in the red LED treatment by increasedplant growth parameters, especially compactness and root morphology, as compared with other treatments.

Effect of Silicate Fertilizer on Growth, Physiology and Abiotic Stress Tolerance of Chinese Cabbage Seedlings

Ngoc-Thang Vu(넉탕부),Si-Hong Kim(김시홍),Seung-Yeon Kim(김승연),Ki-Young Choi(최기영),Il-Seop Kim(김일섭) (사)한국생물환경조절학회 2015 생물환경조절학회지 Vol.24 No.2

규산은 작물의 필수원소에는 포함되어있지 않으나, 화본과 작물을 중심으로 내도복성과 병충해 저항성의 향상 , 군락구조 개선에 의한 광합성 능력의 향상 등에서 폭 넓게 그 유용성이 알려져 왔으며, 최근에는 원예작물에서도 규산질 비료의 시용이 수량이나 병충해저항성을 향상시키는 효과가 입증되고 있어 친환경농업 관점에서도 주목을 밭고 있다. 본 실험은 배추 육묘 중 규산질 비료의 시용이 묘소질과 저온, 고온, 건조 등 환경내성에 미치는 영향을 검토하기 위하여 수행하였다. 규산염 처리농도를 8, 16, 32, 64 및 128mM로 설계하여 주 2회 관주 처리 하고, 처리 3주 후에 생육조사 및 스트레스 내성에 대해 평가하였다. 생육조사 결과, 8, 16 및 32m의 농도에서는 대부분의 생육지표가 대조구에 비해 약간 증가하는 경향을 보였으나 8mM처리만 제외하고 통계적 유의차는 나타나지 않았다. 고농도인 128mM의 규산 처리구에서는 모든 생육 지표가 감소하였다. 총 뿌리 면적, 뿌리 길이 및 근단 수는 8, 16 및 32mM의 농도에서 증가했지만 64 및 128mM의 처리구에서는 감소하였다. 규산 처리 농도가 증가함에 따라 증산 속도는 감소한 반면 기공확산 저항은 증가하는 경향을 보였다. 상대적 이온 누출율도 대조구에 비해 규산염 처리구에서 감소되었으나, 처리 농도간 유의차는 나타나지 않았다. 규산처리에 의해 고온과 저온 장해 지표도 감소되었으며, 농도간에는16과 32mM이 가장 효과적이었다. 규산처리에 따라 건조내성도 증가하여 대조구는 단수 후 3일째부터 위조되기 시작하여 5일째는 전개체가 위조하였으나, 규산처리구는 4일(8, 64, 128 mM) 또는 5일(16과 32mM) 부터 위조가 시작되어 6일(8mM)이나 7일(16, 32 ,64및 128 mM)이 지나서야 모든 공시 개체가 위조되었다. The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.

Growth, Physiology, and Abiotic Stress Response to Abscisic Acid in Tomato Seedlings

Ngoc-Thang Vu,강호민,김영식,최기영,김일섭 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.3

The effect of abscisic acid (ABA) on growth, abiotic stress tolerance, and physiology of tomato seedlings was investigated. To examine the effect of ABA concentration on growth and abiotic stresses, six ABA concentrations (0, 10, 50, 100, 150, or 200 mg·L-1) were applied by foliar spraying once a day for 10 days. The effect of ABA application number was also studied by using different timing at one ABA concentration (100 mg·L-1) once a day for 1, 3, 5, 7, and 9 days. The effect of ABA on physiology of tomato seedlings was examined by using two concentrations (50 and 100 mg·L-1) as compared to the control (non-ABA). Foliar application of ABA decreased the growth characteristics of tomato seedlings in a concentration-dependent manner; however, no statically significant difference was observed between the 50 and 100 mg·L-1 treatments. Furthermore, although growth parameters decreased statistically with increasing number of ABA treatments, there was no difference between the 3 and 5 application treatments. Application of ABA enhanced stress tolerance (cold and drought) of tomato seedlings by delaying the starting time of wilting point in drought conditions and reducing the relative ion leakage and chilling injury index in low temperature in all treatments. The transpiration rate decreased significantly, while stomatal diffusive resistance increased significantly with increasing ABA concentration. The relative water content decreased significantly during the period without irrigation. However, relative water content increased with increasing ABA concentration. The ABA enhanced drought tolerance of tomato seedlings by delaying the start time of wilting point from day 3 in the control to day 5 and 7 in the 50 and 100 mg·L-1 treatments, respectively. Integrating this result data, we can determine the ABA’s ability to maintain of seedling quality at low temperature and water deficit condition.

Determinants of Capital Structure:The Case in Vietnam

VU, Thu Minh Thi,TRAN, Chung Quang,DOAN, Duong Thuy,LE, Thang Ngoc Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.9

This is a quantitative research, underpinned by the philosophy of natural science and deduction approach that examines the impact of the various aspects of corporate governance mechanism on the choice of capital structure of Vietnamese listed firms. We focus on the effect of factors such as the board size, the board independence, and especially different ownership structures, which include the managerial ownership, the state ownership, the concentrated ownership, and the foreign ownership. They are the main scopes of corporate governance and are supposed to be relevant to determine the corporate financing choice. To explain the causal relationship between factors, we construct the regression model and then test it by using different statistical method approaches, including the pooled OLS, the fixed effects model, and the random effects model. Data are collected from 336 firms with shares listed in the Ho Chi Minh City Stock Exchange in Vietnam, totaling 1583 observations. Overall, the results reveal that the board size, state ownership, and concentrated ownership have positive impact on the firm's capital structure, whereas foreign ownership appears to have negative influence on the capital structure. The research does not find evidence of a the correlation between board independence, managerial ownership and corporate capital struture.

The Effect of Social Capital on Social Entrepreneurial Intention among Vietnamese Students

HA, Ngoc Thang,DOAN, Xuan Hau,VU, Trong Nghia,NGUYEN, Thi Phuong Linh,PHAN, Thanh Hoa,DUONG, Cong Doanh Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

This study develops the model to estimate the links between social capital, social entrepreneurial self-efficacy, perceived desirability and social entrepreneurial intention. Besides exploring the direct impacts of social capital, social entrepreneurial self-efficacy, and perceived desirability on social entrepreneurial intention, this study also focus on discovering the mediating roles of perceived desirability and social entrepreneurial self-efficacy on this relationship. Throughout adopting measures from some previous studies, the authors design the questionnaires and distribute to students in Vietnam. The study presents some demographic information of 289 students, who are studying at university and colleges in Vietnam. Then, the validity and reliability of scales are assessed using the value of Cronbach's alpha, Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). In addition, by utilizing the structural modeling structure (SEM), the authors show that social capital plays the important role in shaping social entrepreneurial self-efficacy, perceived desirability, and social entrepreneurial intention. Interestingly, besides the direct effects on social entrepreneurial intention, perceived desirability and social entrepreneurial self-efficacy also mediate the correlation between social capital and social entrepreneurial intention. Also, with the interesting findings of the study, the authors propose several recommendations for policy-makers, educators and academics to promote the social entrepreneurship and innovation among Vietnamese students.