• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.217-221
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• 2017

The ptaquiloside is a carcinogenic compound from bracken fern (Pteridium aquilinum L). This study was to evaluate the content of ptaquiloside in bracken fern by various processing methods. The processing methods were heated and immersed time, water exchange number, and so on. Akali hydrolysis and solvent fractionation of ptaquiloside in bracken fern leads to the non-toxic and chemically stable pterosin B. The contents of pterosin B was analyzed by UPLC-MS/MS on mobile phase 3 mM ammonium acetate and methanol. The contents of total pterosin B in non-processing bracken fern in water extraction was 81.0 mg/kg and toxic ptaquiloside of them was 46.4 mg/kg. The heating time of 5 minutes removed 60% about the contents of pterosin B in the bracken fern, and two-thirds of them were already non-toxic pterosin B, namely were not transfered from ptaquiloside. Additional immersed time (12h), the pterosin B in bracken fern was 10 mg/kg, it was removed 87.6% and once every hour, water exchange times were removed 99.5% in comparison with them of untreated bracken fern and two-thirds of them were non-toxic pterosin B. To remove of ptaquiloside in bracken fern, heat, immersion, and water exchange times shall be carried out simultaneously.

• Economic and Environmental Geology
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• v.57 no.1
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• pp.93-105
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• 2024

Chilgok Geummubong tree fern fossil site is the type locality where tree fern stem fossils (Cyathocaulis naktongensis) were first discovered by Tateiwa in 1925. Recognized for its academic value, it was designated as a natural monument in the 1930s during the Japanese colonial period, and preserved and managed for over 90 years. However, at the time of discovery, the stratigraphic level of tree fern fossils could not be located because the fossils were fragments detached from the rock body, and thus the Geummubong area where the conglomerate/sandstone layers of the Nakdong Formation are distributed, has been designated as a cultural heritage area. Only in the 2000s, when tree fern fossils were directly recovered from the outcrops near the designated area, the sedimentary rock facies containing the fossils were interpreted, and the anatomical characteristics of the Mesozoic tree fern fossils could be described and identified as a species level. Such studies are, in these days, redefining classification criteria done by Japanese paleontologist, Ogura. That is, Korean researchers pointed out that the classification criteria of the tree fern fossils (Cyathocaulis) reported early from Chilgok were ambiguous, and the possibility that the two species were the same species was suggested. In addition, it is necessary to reorganize designated areas as a way to resolve social conflicts and civil complaints caused by various regulations that have continued for a long time.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.801-807
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• 1988

Antithiamine activity of raw and processed brackens (Pteridium aquilinum) was evaluated by means of the thiochrome fluorescence and Lactobacillus viridescens bioassay methods and inter-related with the phenolic content and degree of browning. As blanching time of bracken elapsed, its antithiamine activity was enhanced whereas the phenolic content and brewing declined. Increased salt concnetrations in boiling water also raised the antithiamine activity, phenolic content and browning of raw bracken. When dried bracken was treated with sodium bicarbonate solution or soaked in running water, its antithiamine activity greatly decreased along with the increased phenolic content and browning. Heat cooking of bracken brought about a slight decrease in the antithiamine activity, phenolic content and browning. It was concluded that antithiamine activity existing in raw bracken Is reduced by various treatments, particularly by soaking in running water and that phenolics in bracken may play an important role in thiamine decomposition.

• Korean Journal of Plant Taxonomy
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• v.45 no.2
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• pp.114-135
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• 2015

The taxa of Dryopteris subg. Erythrovariae are variable in morphology, resulting in taxonomic confusion in delimiting taxon boundaries. We examined the morphological characteristics of the Korean members of subg. Erythrovariae to clarify their taxonomic identities and relationships. The shapes of the blades, pinnae, and pinnule apices, the shapes and colors of the scales, and the positions of sori were useful for delimiting the Korean taxa of the subgenus. Based on the results of this study and evidence from previous studies, 13 taxa comprising 12 species and one variety of Dryopteris subg. Erythrovariae were recognized in Korea. Descriptions of all Korean taxa of the subg. Erythrovariae and a key to the species are provided. The descriptions presented here are based on field observations and the examination of some 1,000 specimens from the major herbaria of the world.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.95-101
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• 2014

This study was conducted to analyze the pattern of growth and phenological characteristics of Mankyua chejuense B.-Y. Sun, M.H. Kim & C.H. Kim, which belong to the Ophioglossaceae family. M. chejuense asexually reproduced using rhizomes, and a clone of the species grew up to 52 cm based on root growth and new leaves was produced from rhizomes. The development of leaves were divided into four stages; leaf emergence-separation and growth of leaf-sporophyll maturation-senescence. Most leaves emerged in July and August with high temperatures and precipitation and most leaves reached full expansion during September-October and died during April-May next year. The life span of leave was 10 months, from July to April, and the start of leaf senescence varied depending on the habitat environment and this might result from micro environmental differences among the habitats.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.35-45
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• 2012

In order to characterize the habitat trait and vegetation structure of M. chejuense(Ophioglssaceae), endangered plant in Korea, we set 12 permanent quadrats in Jocheon-Sunhyul Gotzawal Wetland Region of Jeju Island, and surveyed the temporal pools, vegetation structure and counted the population size of the endemic rare plant. M. chejuense distributed in the vernal pools with a variety of shape, area of 150-$400m^2$, depth of 0.4-2.0m and slope of 3-$10^{\circ}$, at altitude of 88-165m in lowland area in Gotjawal Wetland Region, Jeju Island. The soil has a thin layer and high water content all the seasons. The population appeared with a density range of 1-423/pool in the boundary area of the wetlands under higher tree coverages(80-100%) in the deciduous forest communities. Vegetation wsa classified into five plant communities such as Ulmus parvifolia community, Cudrania tricuspidata community, Rosa multiflora community, Ardisia japonica community, Ophiopogon japonicus community. These results means that M. chejuense potentially has a shortage to evergreen plant succession, litter accumulation and water drainage, thus it is need to sustainable wetland environmental condition in the deciduous forest community for its sounded conservation.

• Research in Plant Disease
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• v.25 no.3
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• pp.143-148
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• 2019

An outbreak of new disease with leaf and stem blight symptom occurred at bracken-growing fields in Namhae-gun, Gyeongsangnam-do, Korea during the last 4 years. This new disease caused significant yield losses on bracken production in this area. We have collected diseased leaves and stems showing the blight symptom in May, July, and October 2018 to investigate causal pathogens. A total of 92 fungal isolates were obtained from the diseased samples and their pathogenicity was tested on healthy bracken leaves. From the total isolates, 22 isolates were able to produce the leaf blight symptom similar to the original one found in the fields. To identify two fungal pathogens which showed higher virulence levels compared to other pathogenic isolates, we constructed phylogenetic trees using the nucleotide sequences of genes for ribosomal RNA, RNA polymerase beta subunit, beta tubulin, and internal transcribed region. Most phylogenetic trees constructed indicate that both isolates, which are identical to each other, reside in a clade of the genus Didymella and possibly similar to D. rumicicola or D. acetosellae. Nevertheless, the exact identification of these pathogens at the species level needs further investigations. This is the first report of a blight disease on bracken by Didymella sp.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2007.11a
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• pp.349.1-349.1
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• 2007

• Proceedings of the Plant Resources Society of Korea Conference
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• 2007.11a
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• pp.349.2-349.2
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• 2007

• Monthly Korean Chicken
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• v.16 no.4
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• pp.100-101
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• 2010