• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.608-613
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• 2016

Arbuscular mycorrhizal fungi (AMF) spore propagation and long term maintenance is still a complicated technique for farmers. The use of AMF for their ability to promote plant growth and protect plants against pathogen attack and environmental stresses demands AMF propagation for large scale application. This study aimed to propagate AMF spores by trap culture technique and assess their ability to propagate with different host plants in a continuous plant cycle. Mycorrhizal inoculation by trap culture in maize resulted in longer shoots and roots than sudangrass plants. Increase in dry weight with higher percentage also was observed for maize plants. After first and second plant cycle, maize plants had the higher percentage of mycorrhizal response in terms of colonization and arbuscules than sudangrass. Maximum in spore count also achieved in the pots of maize plants. The results show that maize plant is more suitable host plant for AMF spore propagation and trap culture technique can be used effectively to maintain the AMF culture for long time.

• Architectural research
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• v.8 no.1
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• pp.37-45
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• 2006

A fungal spore transportation model that accounts for the concentration of airborne indoor spores and the amount of spores deposited on interior surfaces has been developed by extending the current aerosol model. This model is intended to be used for a building with a mechanical ventilation system, and considers HVAC filter efficiency and ventilation rate. The model also includes a surface-cleaning efficiency and frequency that removes a portion of spores deposited on surfaces. The developed model predicts indoor fungal spore concentration and provides an indoor/outdoor ratio that may increase or decrease mold growth risks in real, in-use building cases. To get a more useful outcome from the model simulation, an uncertainty analysis has been conducted in a real building case. By including uncertainties associated with the parameters in the spore transportation model, the simulation results provide probable ranges of indoor concentration and indoor/outdoor ratio. This paper describes the uncertainty quantification of each parameter that is specific to fungal spores, and uncertainty propagation using an appropriate statistical technique. The outcome of the uncertainty analysis showed an agreement with the results from the field measurement with air sampling in a real building.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.454-461
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• 2017

This study was conducted to investigate the optimal conditions for spore germination, prothallus propagation, sporophyte formation, and seedling growth in Polystichum braunii (Spenn.) $F{\acute{e}}e$. The rate of spore germination and early prothalium development was high in Knop (41.2%), which had low mineral content. The optimal medium for prothallus propagation and sexual organ formation was 2MS medium (2% sucrose). Among the various mixtures of cultivation soil (bedding soil, peat moss, perlite, and decomposed granite), a mixture of bedding soil and decomposed granite at a ratio of 2:1 (v:v) had a positive effect on sporophyte formation (276.3 ea/$7.5m^2$). The most efficient conditions for promoting the growth of sporophytes were pots filled with only bedding soil.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.46-58
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• 2017

This study was conducted to investigate the optimal conditions for spore germination, prothallus propagation, sporophyte formation and seedling growth in Microlepia strigosa (Thunb.) C. Presl. Spore germination and prothallus development were promoted by low concentrations of Knop medium nutrient solution. The optimal medium for prothallus propagation and antheridium formation was 2X MS medium with 3% sucrose. The activated charcoal content of the medium did not affect prothallus proliferation. Among the various combinations of culture soil (bedding soil, peat moss, perlite and decomposed granite), a mixture of bedding soil, peat moss and decomposed granite at a ratio of 1 : 1 : 1 (v : v : v) had a positive effect on sporophyte formation. The most efficient conditions for promoting the growth of whole plants (sporophyte seedlings) were 50 - cell plug trays filled with a mixture of bedding soil and decomposed granite at a 2 : 1 (v : v) ratio.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.11-11
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• 2021

Ferns have been consumed as food in many countries for centuries. As rich sources of protein, fiber, minerals, vitamins, essential amino acids, and fatty acids, ferns provide important nutrients to humans. Eastern bracken (Pteridium aquilinum var. latiusculum (Desv.) Underw. ex A. Heller) is the most popular edible fern in South Korea where, additionally, it has long been used as an edible wild leaf vegetable. Recently, the production of eastern brackens in South Korea (2018) has reached 14,032 tons, for an annual revenue of 83.5 billion won, and even more eastern brackens are marketed if imports are taken into account as well. Most of the common ferns can be propagated using spores. However, fern farmers cultivate seedlings through traditional propagation methods, such as root pruning or rhizome division. These propagation methods exhibit limitations in forming roots and growing-points and are labor intensive. Quality seedlings of eastern bracken can be obtained through spore propagation, but the spores are fine and difficult to handle in the field. In addition, it would require appropriate environmental control. The production of synthetic seeds using encapsulation technology is easy to establish and it can be used to achieve high productivity at low cost. Synthetic seeds contain explants embedded into a seed foam, and they overcome the limitations of micropropagation and offer the possibility of using plug seedlings. Synthetic seed matrix, such as sodium alginate, has the advantages of low cost, low toxicity, and gel stability. The present study aimed to develop and produce synthetic seeds for the commercial exploitation of eastern bracken. Furthermore, we verified spore germination and the extent of gametophyte and sporophyte development achieved with our new synthetic seeds, whose production was intended to solve current problems with the handling, storage, and transportation of eastern bracken.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.480-489
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• 2017

We investigated a suitable method for in vitro germination of spores, propagation of prothalli, and the formation of sporophytes in the fern Dryopteris nipponensis Koidz. Spore germination rate was relatively high regardless of culture medium. Prothallus development was faster in Knop medium than in Murashige and Skoog (MS) media. Prothalli used in all experiments were obtained from germinated spores, and were cultivated in different concentrations of media components. The active formation of sexual organs such as antheridium made 1MS medium suitable for prothallus propagation, although there was a lower propagation ratio compared to Knop medium. Growth and morphogenesis of prothalli were most effective on 1MS medium containing 2% sucrose, and 60 mM of total nitrogen source with 20:40 mM ratio of $NH_4{^+}:NO_3{^-}$. To select a suitable soil composition for sporophyte formation, ground prothalli were cultivated on single and mixed soils using bed soil, peat moss, perlite, and decomposed granite for 14 weeks. Bed soil promoted sporophyte formation and growth regardless of single or mixed use. In particular, a mixture of bed soil and decomposed granite in a 2:1 ratio (v:v) led to accelerated sporophyte formation ($0.83/cm^2$).

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.29-29
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• 2015

Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.400-406
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• 2016

This study was conducted to determine the optimal conditions of growth medium, temperature, and light quality for efficient propagation of Lygodium japonicum spores. The rate of spore germination and prothalium development was high in Knop and 1/8MS and 1/4MS media, which had low mineral content; in particular, the germination rate exceeded 74%, and the germinated spores developed into heart-shaped prothallia. However, in Knop‘s medium with the lowest mineral content, a rapid prothallium senescence was observed; in 1/4MS medium, prothallium development was delayed. Germination rate increased with the increase in temperature and reached its maximum, 86.7%, at 30℃; however, at this temperature, the prothallia were thinner and abnormal development of rhizoids was observed compared to normally developed prothallia and rhizoids at 25℃. Therefore, the results suggested that the optimal temperature for L. japonicum spore germination was 25℃. The rate of germination was also measured under different light conditions, and the highest rate of 90.6% was observed under LED red light compared to fluorescent (77.2%) or LED blue (5.4%) lights. The germinated spores developed into heart-shaped prothallia under LED red light; however, 15 days after seeding, prothallium development decreased and the became elongated. In contrast, a normal and continuous development of heart-shaped prothallia was observed under fluorescent light.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.350-355
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• 2004

This experiment was carried out to screen the aeroponically grown host plants suitable for the mass propagation of arbuscular mycorrhizal fungi (AMF) inoculum and clarify the effect of P levels in nutrient solution on the growth of aeroponically grown sweet potato (Ipomoea batatas L.), AMF infection, and mass propagation of mycorrhizal spores, etc. Amount of biomass of host plant became higher, as the P levels in nutrient solutions increased from 5 to 20 M. AMF infection rates in mycorrhizal roots increased in higher P levels in nutrient solution, and decreased in lower parts of mycorrhizal roots by about 18.6-26.0%. About 586 mycorrhizal spores per 1 g fresh root were formed at 16 weeks after inoculation of mycorrhizal inoculum. Total of 830,479 mycorrhizal spores were propagated in each plot.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.83-86
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• 1969

The present investigations were made with the purpose of elucidating the seasonal variation in total nitrogen content of Gelidium amansii. Monthly samples were collected from the sea near pusan, from August 1957 to June 1959. The results obtained have been summarized as follows: The maximum total nitrogen content of Gelidium amansii was observed during the months of January and February, and the minimum content was observed in June and July Thus the total nitrogen content of Gelidium amansii exhibited a considerable periodic change throughout the year. The recommended harvest time of Gelidium amansii with regard to total nitrogen content, is from May to October, but on the other hand the proper harvest time is from May to June, with respect to the season of spore-formation and its propagation.