• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.27-27
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• 2021

Yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson], a member of Compositae plants, has sweet taste and crisp texture. Unlike other Andean root crops such as potato and sweet potato, the cultivation area of yacon has increased recently, since it is known to have large content of fructooligosaccharides (FOS). Since there are no yacon varieties bred in Korea, we have been trying to create new genetic resources using gamma-ray. The optimal gamma-ray dosage for mutation breeding in yacon was investigated. Crown bud and green bud of yacon were exposed to doses of gamma rays from 20 Gy to 80 Gy, and subsequently planted in a greenhouse. After 50 days of sowing, the survival rates and growth decreased rapidly at doses above 40 Gy, while all of crown bud individuals died above 60 Gy. The median lethal dose (LD50) of crown bud and green bud was 22.4 and 36.6 Gy, and the median reduction doses (RD50) for plant height, fresh weights, and tuberous root weight were 20-40 Gy, respectively. A dose of 20-40 Gy was found to be optimal for mutation breeding in yacon. Considering the growth factors, the optimum doses were determined to be within the range of 20-40 Gy for the selection of useful mutant lines. M2-M3 mutant lines were obtained from 20-60 Gy gamma-ray-irradiated M1 plants through clonal propagation. These mutant lines will be used for the development of a new variety of yacon plant with high FOS and no crack tuberous root.

• Journal of Environmental Impact Assessment
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• v.25 no.2
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• pp.103-123
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• 2016

This study is a comparison of the flora and case studies distributed in Gulup-do Ongjingun, Incheon. The numbers of vascular plants were summarized as 282 taxa including 81 families, 201 genera, 252 species, 3 subspecies, 22 varieties and 5 forms. The Raunkiaer life forms are analyzed in hemicryptophytes were 66 taxa (23.4%) in dormancy form, non-clonal growth ($R_5$) were 160 taxa (56.7%) in propagation form of radicoid form, having no special modification for dissemination ($D_4$) were 197 taxa (48.6%) in propagation form of disseminule form, erect form (e) were 117 taxa (41.5%) in growth form. The halophytes were 23 taxa including Salsola collina, Asparagus oligoclonos and so on. The rare plants were 7 taxa including Pyrrosia hastata (VU), Senecio nemorensis (VU) and so on. The Korean endemic plants were 5 taxa including Hepatica insularis, Lespedeza maritima and so on. In the specific plants by floristic region were 38 taxa, a degree I were 23 taxa (Dictamnus dasycarpus, Vitex rotundifolia and so on), 6 taxa of a degree II (Morus cathayana, Euphorbia esula and so on), 8 taxa of a degree III (Pyrrosia hastata, Rhodotypos scandens and so on), Senecio nemorensis of a degree V and degree IV were not found. The naturalized plants were 17 taxa including Robinia pseudoacacia, Bromus tectorumand so on. Of those Ambrosia artemisiifolia is a invasive alien plants. Naturalization rate (NR) was 6.0% of all 282 taxa of vascular plants and urbanization index (UI) was 5.3% of all 321 taxa of naturalized plants. Gulup-do and adjacent Baega-do were locally investigated field work and it summarizes the results of a total of 41 islands literature in Ongjin-gun and Ganghwa-gun, Incheon including uninhabited islands, Baengnyeong-do, Daecheong-do and so on. The average number of species were each analyzed in about 89 taxa, rare plants are about 2 taxa, endemic plants are about 1 taxa, naturalized plants are about 4 taxa. This study was the comparison of the flora and literature distribution case that the Gulup-do maintain the naturalness and continuously conducted to explore the future conservation measures the adjacent islands.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.61-62
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• 2003

Clonal propagation of high-value forest trees through somatic embryogenesis (SE) has the potential to rapidly capture the benefits of breeding or genetic engineering programs and to improve raw material uniformity and quality. A major barrier to the commercialization of this technology is the low quality of the resulting embryos. Several factors limit commercialization of SE for Corsican pine, including low initiation rates, low culture survival, culture decline causing low or no embryo production, and inability of somatic embryos to fully mature, resulting in low germination and reduced vigour of somatic seedlings. The objective was to develop a Corsican pine maturation medium that would produce cotyledonary embryos capable of germination. Treatments were arranged in a completely randomized design. Data were analyzed by analysis of variance, and significant differences between treatments determined by multiple range test at P=0.05. Corsican pine (Pinus nigra var. maritima) cultures were initiated on modified !P6 medium. Modifications of the same media were used for culture multiplication and maintenance. Embryogenic cultures were maintained on the same medium semi solidified with 2.5 g/l Gelrite. A maturation medium, capable of promoting the development of Corsican pine somatic embryos that can germinate, is a combination of iP6 modified salts, 2% maltose, 13% polyethylene glycol (PEG), 5 mg!l abscisic acid (ABA), and 2.5 g/l Gelrite. After initiation and once enough tissue developed they were grown in liquid medium. Embryogenic cell suspensions were established by adding 0.951.05 g of 10- to 14-day-old semisolid-grown embryogenic tissue to 9 ml of liquid maintenance media in a 250ml Erlenmeyer flask. Cultures were then incubated in the dark at 2022$^{\circ}$C and rotated at 120 rpm. After 2.53 months on maturation medium, somatic embryos were selected that exhibited normal embryo shape. Ten embryos were placed horizontally on 20 ml of either germination medium ($\frac{2}{1}$strength Murashige and Skoog (1962) salts with 2.5 g/l activated charcoal) or same medium with copper sulphate adjusted to 0.25 mg/1 to compensate for copper adsorption by activated carbon. 2% and 4% maltose was substituted by 7.5% and 13% PEG respectively to improve the yield of the embryos. Substitution of' maltose with PEG was clearly beneficial to embryo development. When 2% of the maltose was replaced with 7.5% PEG, many embryos developed to large bullet-shaped embryos. At latter stages of development most embryos callused and stopped development. A few short, barrel-shaped cotyledonary embryos formed that were covered by callus on the sides and base. When 4% of the maltose was removed and substituted with 13% PEG, the embryos developed further, emerging from the callus and increasing yield slightly. Microscopic examination of the cultures showed differing morphologies, varying from mostly single cells or clumps to well-formed somatic embryos that resembled early zygotic embryos only liquid cultures with organized early-stag. A procedure for converting and acclimating germinants to growth in soil and greenhouse conditions is also tested. Seedling conversion and growth were highly related to the quality of the germinant at the time of planting. Germinants with larger shoots, longer, straighter hypocotyls and longer roots performed best. When mature zygotic embryos germinate the root emerges, before or coincident with the shoot. In contrast, somatic embryos germinate in reverse sequence, with the cotyledons greening first, then shoot emergence and then, much later, if at all, the appearance of the root. Somatic seedlings, produced from the maturation medium, showed 100% survival when planted in a field setting. Somatic seedlings showed normal yearly growth relative to standard seedlings from natural seed.