• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.55-62
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• 2010

This study was conducted to find out the effect of diniconazole treatment by seed soaking on the stretching of tomato and cucumber seedlings. The emergence rate of tomato and cucumber seed was decreased as diniconazole concentration was higher and soaking period was longer. The emergence rate of tomato seedlings was lower as the soaking period was longer in $1mg{\cdot}L^{-1}$ concentration treatments, although there was no significant difference. The other concentration treatment (10, 50, and $100mg{\cdot}L^{-1}$) reduced emergence rate of tomato seedlings outstandingly in higher concentration and longer treated period, but 90% of treated seeds emerged at 10 days after sowing. As the concentration of diniconazol was higher and soaking period was longer, plant height and growth rate of seedlings were retarded. There covery of internodes growth was faster in lower concentration and shorter soaking period. The top and root fresh weight and dry weight of tomato and cucumber seedlings was not influenced by $1mg{\cdot}L^{-1}$ concentration, but these growth characteristics were reduced in higher concentration and longer soaking period. The dwarfed cucumber seedlings treated by diniconazol showed normal growth rate after planting and their male and female flower was set normally. These results suggest that the proper concentration and soaking period of diniconazol may be $10mg{\cdot}L^{-1}$ concentration for 12 hours in tomato seed, and $1mg{\cdot}L^{-1}$ concentration for 24 hours in cucumber seed.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.43-49
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• 2014

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.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.167-174
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• 2017

To identify the appropriate irrigation level for Pinus densiflora, a common reforestation species in Korea, we investigated their growth response characteristics according to different irrigation treatment levels for producing container seedlings with relatively high growth rate for higher survival rate when planted at the reforestation site. The container seedlings including control seedlings (no irrigation was applied) were grown in 104-cell trays were irrigated for 8 weeks from 15 weeks after seeding, at intervals of 1, 2, 3, 5, 7, 10, and 15 days. Analysis of the height growth, root collar diameter growth, and dry matter production of the container seedlings according to irrigation showed that the highest growth reaction was observed for the irrigation interval of 1 day. A shorter irrigation cycle resulted in better growth of the container seedlings, but overall, longer total root length were observed with an irrigation cycle of 3 days compared with cycles of 1 or 2 days. Quality index (QI) was the highest for the irrigation interval of 1 day, and tended to decrease with increase in the irrigation interval. Thus, it was determined that irrigation at intervals of 1-2 days was appropriate for growing Pinus densiflora container seedlings.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.50-57
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• 2020

BACKGROUND: Biochar is used in various environmental fields, such as water quality and soil restoration, and affects soil fertility and nutrient cycling. Also, when crops are grown on biochar-applied soil, their characteristics may be affected. Biochar is used especially with commercial vegetable seedlings. METHODS AND RESULTS: The objective of this study was to determine the effects of biochar content in seeding mixes on early growth of lettuce (Lactuca sativa L.), Chinese cabbage (Brassica rapa L.), and red pepper (Capsicum annuum L.). Treatments consisted of a control (0: 10, ratio of biochar to seeding mixes (w/w)), 1: 9 (biochar 10%), 3: 7 (biochar 30%), 5: 5 (biochar 50%), and 7: 3 (biochar 70%). The biochar was made from risk husk and had a C/N ratio of 104. As the mixing ratio of biochar increased, pH increased whereas EC and nitrogen content decreased. The highest phosphorus content was with the treatment of 30% biochar, while there were significant increases in the weight of lettuce seedlings and concentrations of T-N, P₂O₅, K₂O, MgO, and Na with the treatments of 30% and 50% biochar. Although the weight of Chinese cabbage seedlings increased with the treatment of 10% biochar, the increase was not statistically significant. Also, there was an increase in the weight of red pepper seedlings with the treatment of 30% biochar, but the increase was not statistically significant. With increases in the biochar mixing ratio, the K₂O concentration of red pepper seedlings increased, but the concentrations of P₂O₅, CaO, MgO, and Na decreased. It was believed that this was because of absorption inhibition by calcium-phosphate formation in the seeding mixes owing to increased pH. CONCLUSION: In conclusion, adding biochar to seeding mixes is considered to be an important mean for growing healthy vegetable seedlings. More field experiments are needed to verify the effect of biochar on vegetable crop growth over the entire growing season.

• Korean Journal of Organic Agriculture
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• v.27 no.2
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• pp.205-224
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• 2019

This study was carried out in order to evaluate the growth promotion effects on tomato crops and to assess the mineral nutrient concentrations of farm-made liquid fertilizers used in organic cultivation in South Korea. We hope that this study will help to develop of a standardized manufacturing technique for these organic liquid fertilizers. We collected 62 farm-made liquid fertilizers made from various raw materials including fish, seaweed, food scraps, plant and crop by-products, and other materials. Two groups of tomato seedlings were treated at different times, one at 20 days and the other at 40 days after sowing. We used both foliar and soil applications. These seedlings were treated using liquid fertilizers at various dilution rates (x1000, x500 and x100). When foliar application was used, seedlings after 20 days had a 20-30% increase in shoot fresh weight with 47-48 fertilizers and seedlings after 40 days had a 20-30% increase in shoot fresh weight with 17-32 fertilizers. When soil application was used, seedlings after 20 days had the same increase in shoot fresh weight with 30-31 fertilizers and seedlings after 40 days also saw the same increase with 6-7 fertilizers. Therefore, our studies showed that application of liquid fertilizers to seedlings 20 days after sowing was most effective and that foliar treatment was more effective than soil treatments. We also observed that the higher the concentrations of fertilizer, particularly when applied twice rather than just once, the higher the rates of growth, which promoted shoot fresh weight more than plant height. Our results imply that mineral nutrients in liquid fertilizers seem to be the probable cause for the growth promotion observed in this study. However, more study is required to determine exactly which mineral nutrients are most effective.

• Journal of Life Science
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• v.21 no.4
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• pp.502-508
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• 2011

The purpose of this study was to evaluate the methods of identifying zygotic seedlings of crosses between 'Morita unshiu' (Citrus. unshiu Marc.) and 'Ponkan' (C. reticulata Blanco). In order to investigate the frequency and position of zygotic seedlings and to determine the efficiency of zygotic seedling identification, random amplified polymorphic DNA (RAPD) and sequence-related amplified polymorphism (SRAP) were performed using UBC (9, 27, 229, 230, and 254) primers and F4/R27, F7/R14, F12/R10, and F44/R62 primer sets, respectively. A total of 37 putative zygotic seedlings out of 55 individuals were selected by RAPD and SRAP. The F7/R14 primer pair showed a screening ability of 45.5% (25/55), whereas the primer UBC27 revealed the highest efficiency of zygotic seedling identification (50.9%, 28/55). When both UBC27 and F7/R14 were properly used for selection of hybridized seedlings of 'Morita unshiu' (C. unshiu Marc.) and 'Ponkan' (C. reticulata Blanco), screening efficiency was increased to 60% (33/55) for putative zygotic seedlings. Thus, it is possible to select putative hybrid zygotic seedlings in an accurate and effective manner by RAPD and SRAP.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.323-333
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• 1995

The effects of plant hormones (NAA, $GA_3$ and BA) and light qualities (white, red, green and blue light) on the changes of reducing sugar contents and invertase isozyme activities in leaves of maize (Zea mars L.) and mung bean (Phseolw radiatus L.) seedlings were investigated. NAA accelerated the increase of reducing sugar contents and invertase isozyme activities, on the contrary, $GA_3$ had little effect in the accumulation of reducing sugar and in the increase of enzyme activities from the leaves of maize and mung bean seedlings. On the other hand, BA accelerated an increase in the activities of the invertase isozyme from the leaves of mung bean seedlings whereas it had little effect in the increase of the enzyme activities from those of maize seedlings. The accumulation of reducing sugar in leaves of both seedlings was promoted by red light irradiation compared to white light irradiation, while the activities of the enzyme were little affected by various light Qualities. In the simultaneous applications of plant hormone and light quality, NAA with white light was very effective in the increase of reducing sugar contents and the enzyme activities from the leaves of mung bean seedlings, whereas NAA application with blue light showed a prominent enhancement in the reducing sugar contents and the enzyme activities from those of maize seedlings. These results suggest that plant hormone, particularly NAA, may be a more important factor than various light Qualities in the stimulation of invertase activity.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.330-336
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• 2011

A comparative study was conducted on genetic correlation between 12 open-pollinated families (32-year-old) and their one-year-old seedlings for early selection on the fast-growing trait in Pinus densiflora S. et Z.. Those twelve families were divided into three groups such as superior, intermediate, and inferior, on the base of the growth indexes of 32-year-old P. densiflora. The growth performance of the 32-year-old P. densiflora showed significant correlation with the growth traits of their one-year-old seedlings. Dry weights of the seedlings had significant correlation (P < 0.01) with the growth index of the adult plants and its $R^2$ value was 0.597, suggesting that 59.7% of the families could be selected by using dry weights of one-year-old seedlings. Furthermore, the growth rates of seedling heights for superior, intermediate, and inferior groups were 4.568, 3.773, and 3.535, respectively, resulting that seedlings of the superior group grew approximately 1.3-fold faster than those of the inferior group. Therefore, we concluded that two growth traits of one-year-old seedlings dry weight and growth rate were suppose to the early selection factors for the fast-growing trait for P. densiflora.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.70-78
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• 1991

Both long period of summer drought and unusual high water temperature in 1988 caused the harmfull effect to the aquacultural organisms in south coast of Korea. One of those was the mass mortality of arkshell seedlings in Jinhae Bay. The purpose of this study was to verify the effects of environmental factors on arkshell seedlings by investigating not only water quality and food organisms in culturing grounds, but also meteorological conditions. Water temperature in November was higher at $2.0^{\circ}C$ than mean water temperature and the concentration of total inorganic nitrogen and N/P ratio were $0.38{\mu}g-at/l,$ 0.98, respectively which indicated the exhaustion of nutrients, especially nitrogen in the study area. In analysis of phytoplankton population structure, species diversity index(H) , equitability-index(e), species richness $index(d_1)$ were low, but dominance $index({\delta}_2)$ was high at the value of 98.4 and dominant species was Nitzschia pungens. In conclusion, it seems that mass .mortality of arkshell seedlings in November was resulted from the metabolism disorder with poor food organism under the unstable marine environment.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.389-393
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• 2005

This study was carried out to investigate the effects of soil acidification on the growth of 3-year-old Pinus densiflora seedlings grown for 21 weeks in brown forest soils acidified with $H_2SO_4$ solution. The concentrations of Al in the acidified soils were increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was reduced by the addition of the $H_2SO_4$ solution. In addition, there was a strong positive correlation (r=0.97, p<0.01) between the dry weight of the seedlings and the molar (Ca+Mg+K)/Al ratio of the soil. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 50% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil may be a useful indicator for assessing the critical load of acid deposition.