• ALGAE
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• v.37 no.2
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• pp.105-121
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• 2022

Modern seaweed farming relies heavily on seedlings from natural beds or vegetative cuttings from previous harvests. However, this farming method has some disadvantages, such as physiological variation in the seed stock and decreased genetic variability, which reduces the growth rate, carrageenan yield, and gel strength of the seaweeds. A new method of seedling production that is sustainable, scalable, and produces a large number of high-quality plantlets is needed to support the seaweed farming industry. Recent use of tissue culture and micropropagation techniques in eucheumatoid seaweed production has yielded promising results in increasing seed supply and growing uniform seedlings in large numbers in a shorter time. Several seaweed species have been successfully cultured and regenerated into new plantlets in laboratories using direct regeneration, callus culture, and protoplast culture. The use of biostimulants and plant growth regulators in culture media increases the seedling quality even further. Seedlings produced by micropropagation grew faster and had better biochemical properties than conventionally cultivated seedlings. Before being transferred to a land-based grow-out system or ocean nets for farming, tissue-cultured seedlings were recommended to undergo an acclimatization process to increase their survival rate. Regular monitoring is needed to prevent disease and pest infestations and grazing by herbivorous fish and turtles during the farming process. The current review discusses recent techniques for producing eucheumatoid and other valuable seaweed farming materials, emphasizing the efficiency of micropropagation and the transition from laboratory culture to cultivation in land-based or open-sea grow-out systems to elucidate optimal conditions for sustainable seaweed production.

• 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 Environmental Science International
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• v.24 no.10
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• pp.1285-1307
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• 2015

We constructed marine forest to restore barren grounds which are expanding in the east coast of Korea using 2 methods of (1)seedlings transplantation method and (2)underwater floating ropes method. We transplanted 3 macroalgae species, Ecklonia cava, Undaria pinnatifida, and Saccharina. japonica to construct marine forest. Blade length of Undaria pinnatifida on underwater floating ropes was $56.70{\pm}8.69mm$ in April and grew $68.75{\pm}22.30mm$ in May and $70.75{\pm}14.36mm$ in July. Blade length of S. japonica was shown 97.95-143.00mm in April to June. Blade length of Ecklonia cava was $30.50{\pm}1.91mm$ in May, $41.55{\pm}1.84mm$ in August, $45.30{\pm}2.57mm$ in November, 2009 and $45.30{\pm}1.99mm$ in February, 2010. The survey on Dangsa area, Ulsan-city in January, 2009 found a total number of 15 algal species(1 brown algae, 14 red algae species) with the highest variety at 5m depth of A station and the lowest at 8m depth of A and B stations. The March survey showed a total of 24 species (1 green algae, 1 brown algae, 22 red algae species) with the highest variety of 11 at depths of 3m and 5m of B station and the lowest of 6 at 10m of B station. In May, total biomass was 3,755.4g (green algae 1.2g, brown algae 199.0g, red algae 3,555.2g). From January, 2009, we found that E. cava was dominant at the depths of 3m and 5m of A and B stations while Peyssonnelia capensis was dominant at the depth of 8m of A station. The 8m depth of B station was dominated by Acrosorium polyneurum. In May, Grateloupia lanceolata was dominant at 8m depth of A station while other depths were dominated by Phycodrys fimbriata. In June, the dominant species were G. lanceolata at the 3m depth, E. cava at the 5m and P. fimbriata at the depths of 8m and 10m of A station. Under B station, G. lanceolata was dominant at the depths of 3m and 5m while P. fimbriata was dominant at the depths of 8m and 10m.

• Ocean and Polar Research
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• v.42 no.2
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• pp.133-139
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• 2020

The aim of this study is to examine the physiological characteristics of an agarophyte Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N. Norris et Fredericq in the early life stage of tetrasporophytes (2n) and gametophytes (n) to select appropriate seedlings for mariculture. Growth experiments were carried out at the combinations of four temperatures (20, 25, 30, and 35℃) and three light intensity levels (20, 60, and 100 µmol photons m^-2 s^-1) in the two ontogenetic stages: discoid holdfasts and erect sporelings. Holdfast areas and sporeling lengths of tetrasporophytes and gametophytes were estimated after 14 days in culture. Relative growth rates (RGRs) for holdfast areas were 7.08-28.38% day^-1 for tetrasporophytes and 11.58-23.67% day^-1 for gametophytes. At 35℃, holdfasts of tetrasporophytes survived with RGRs of 7.08-23.28% day^-1 but those of gametophytes died. Maximal holdfast growth of tetrasporophytes occurred at 30℃ and 100 µmol photons m^-2 s^-1, which were different from gametophytes (25℃ and 100 µmol photons m^-2 s^-1). RGRs of tetrasporophytic sporelings were 2.93-11.11% day-1 and were between 0.78-10.82% day-1 for gametophytes. Maximal growth of A. vermiculophyllum sporelings occurred at 25℃ and 60 µmol photons m^-2 s^-1 for tetrasporophytes, and at 20℃ and 100 µmol photons m^-2 s^-1 for gametophytes. In conclusion, the present results indicate that carpospores could be used as resources of spore-seedling methods having genetic diversity for mass field cultivation because tetrasporophytes showed higher-temperature tolerance and faster-growing ability than gametophytes of A. vermiculophyllum in the discoid holdfast and sporeling stages.