• Journal of Korean Society of Forest Science
• /
• v.83 no.2
• /
• pp.191-204
• /
• 1994

Due to its topographic complexities and various climatical condition, Korea exhibits diverse forest types. Dominant tree species in this zone are Quercus spp., Betula spp., Zelkova spp., Fraxinus spp., Pinus densiflora, Pinus koraiensis, and Pinus thunbergii ete. Genetic conservation in forest species in Korea there are three ways ; one is in situ, other is ex situ and third is in-facility conservation. In situ conservation include that are the present status of conservation of rare and endangered flora and ecosystem, the reserved forest, the national and provincial park, and the gene pool of natural forests. Ex situ conservation means to be established the new forest from in situ forest stands, progeny and provenance test populations, seed orchard and clone banks, and gene conservation in-facility. As a tool for low temperature storage, several aspects on in vitro system were studied ; (1) establishment of in vitro cultures from juvenile and/or rejuvenated tissues, (2) induction of multiple shoots from the individual micropropagules, (3) elongation of the proliferated shoots. Studies on cold storage for short-and long-term maintenance of in vitro cultures under $4^{\circ}C$ in the refrigerator were conducted. For the cryopreservation at $-196^{\circ}C$, various factors affecting survivability of the plant materials are being examined. The necessity of gene conservation of forest trees is enlarged not only to increase the adaptability for various environments but also to gain the breeding materials in the future. For effective gene conservation of forest trees, I would like to suggest followings ; 1. Forest stands reserved for other than the gene conservation purposes such as national parks should be investigated by botanical and gene-ecological studies for selecting bio-diversity and gene conservation stands. 2. Reserved forest for gene pool should be extented both economically important tree spp. and non-economical species. 3. Reserved forest for progeny test and clone bank should be systematically investigated for the use of Ex situ forest gene conservation. 4. We have to find out a new methodology of genetic analysis determining the proper and effective size of subpopulation for in situ gene conservation. 5. We should develop a new tree breeding systems for successful gene conservation and utilization of the genetic resources. 6. New method of in-facility gene conservation using advanced genetic engineering should be developed to save time and economic resources. 7. For the conservation of species with short-life span of seed or shortage of knowledge of seed physiology, tissue culture techniques will be played a great role for gene conservation of those species. 8. It is are very useful conservation not only of genes but of genotypes which were selected already by breeding program. 9. Institutional and administrative arrangements including legistlation must be necessarily taken for gene conservation of forest trees. 10. It is national problems for conservation of forest resources which have been rapidly destroyed because of degenerating environmental condition and of inexperienced management system of bio-diversity and gene conservation. 11. In order to international cooperation for exchanging data of bio-diversity and gene conservation, we should connect to international net works as soon as possible.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.28 no.1
• /
• pp.41-57
• /
• 1983

The effect of temperature 'during the reduction division stage on the Indica-Japonica rice varieties were studied in artificial temperature-controlled cabinets (Bioclimatic Laboratory). Varieties used were indica-japonica crosses (Suweon 264, Suweon 258, Milyang 29), indica (IR36, Lengkwang) and japonica rice (Jin-heung). The results obtained from this study are summarized as follows. The most sensitive stage to low temperature, the tetrad stage, was observed in each variety with the following auricle distance: Jinheung, -12cm; IR36, -3cm; Suweon264, -9cm; Suweon258, -3cm; Milyang29, -6cm and Lengkwang, +1cm. The tetrad stage occured when the palea elongation was about 50 to 60% of the final palea length at flowering stage in all varieties. The percentage of degenerated spikelets at tetrad as influenced by low-temperature treatment was very low in Jinheung and Lengkwang, but very high in IR36. In indica-japonica crosses only the 7-days treatments had a very high percentage. Between the 4-day and 7-day treatments as well as among all varieties, clear differences were observed in the low temperature induced sterility of 'special spikelets' (upper position grains at tetrad). In the 7-day treatments except in Lengkwang, all varieties showed very high sterility. It appears that the treatments is over the critical limit for treatment. However in the 4-day treatments, the intervarietal differences in sterility were very clear. In Jinheung, sterility was 46.8%; IR36, 67.6%; Suweon264, 60.9%, Milyang29, 62.2%; Lengkwang, 27.8%. A close relationship was observed between fertility and auricle distance. The lowest fertility of special spikelets was at the tetrad stage and the first contraction phase. Before and after the stage there was an increase in fertility. The palea length elongated nearly in a straight line from the spikelet formation stage to flowering. And there was a high correlation between palea length and auricle distance. distance.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.3
• /
• pp.341-346
• /
• 1987

Seven barley varieties were tested under three different vernalization durations for observing the effects of vernalization duration and different growth habit on shoot apex development and heading date. The final leaf number per main stem in 3 and 6 weeks vernalized seedlings did not vary among varieties, but ranged 7 to 14 leaves in non-vernalized seedlings. The winter types had more leaves than the spring types. Days for each leaf emergence in non-vernalization were retarded 1. 3 to 1. 5 days in comparison with 3 or 6 weeks vernalized seedlings. In general, the leaf emergence speed of spring types was faster than that of winter types. The VI stage whose double ridge formed, did not vary in 6 weeks vernalization, but spring (Gangbori & Dongbori 2) and facultative or winter types showed two conspicuous difference patterns. The differences of days to X stage were great among different vernalization duration and varieties; the stage of spring types was reached faster than that of winter types. The early varieties within the same growth habit were reached to X stage faster, and the time of flag leaf emergence showed the similar tendency to the differentiation of X stage. The time of the first rapid stem internode elongation became late as for incompletely vernalized seedlings. The time within the same vernalization duration became later in winter types than in spring types, and even within the same growth habit, the time of early varieties became faster than that of late varieties. The growth habit in especially non-vernalized seedlings had highly significant correlation coefficients with the times of leaf development speed, leaf number per main stem, the first rapid stem internode and young spike elongations, X stage, and flag leaf emergence. However, the relationship between growth habit and time of heading in the field was not close.

• Korean Journal of Weed Science
• /
• v.8 no.3
• /
• pp.309-316
• /
• 1988

Several experiments were conducted to investigate the achene viability and growth characteristics of Eclipta prostrata (L.) L. No dormancy and no after-ripening requirement were found for E. prostrata achenes. When achenes were stored at room temperature, germination did not decrease with up to 5 months storage. Large differences in loss of viability of E. prostrata achenes occurred when different dehydration methods were used. Immediate dehydration resulted in high viability, but slow dehydration resulted in severe loss of viability. Achene viability at shallow burial depths (5 and 10 cm deep) was lower under upland soil conditions than under lowland soil conditions. Seedling growth was greatly reduced when flooding to a depth of 10 cm occurred at or before the 4-leaf stage. Flooding after the 4-leaf stage stimulated stem elongation. Branching started from the second week and usually terminated at the tenth week. Leaf size was determined by the branch which are related to the assimilate supply. Flowering of E. prostrata started during the fifth week after emergence, and mature achenes were produced from the sixth week. Ten to 14 days were needed for the achenes to mature. About 14,000 achenes were produced on each plant. Achene production per week increased from the sixth week to the tenth week and thereafter it declined. The average number of achenes per inflorescence decreased with delay in flowering.

• Korean Journal of Food Science and Technology
• /
• v.30 no.5
• /
• pp.1097-1106
• /
• 1998

Biodegradable edible films were prepared from rice protein concentrates (RPC) made from rice wine meal by alkaline extraction and isoelectric precipitation. The effect of film forming solution pH and plasticizers were studied, and cross-linkers were added to improve mechanical properties and water vapor permeabilities (WVP) of films. Films could be formed within pH $8{\sim}11$ with tensile strength (TS) of 4.3{\sim}5.7\;MPa$. Films produced under pH 11 had the highest TS (5.7 MPa) and the lowest WVP $(0.44\;ng{\cdot}m/m^2{\cdot}s{\cdot}Pa)$. Added glycerol, polyethylene glycol 200 (PEG) and its mixture (GLY:PEG=50:50) as plasticizers also affected the mechanical properties and WVP of films. TS and elongation at break (E) of films at various plasticizer levels were $5.5{\sim}1.0\;MPa$ and $3.6{\sim}24.3%$, respectively. At the same plasticizer concentration, the highest TS was observed when glycerol was used whereas the highest E was measured when mixture was used as plasticizer. WVPs of films with thickness of $60\;{\mu}m$ were $0.39{\sim}0.54\;ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$. WVP of films decreased as the ratio of glycerol/PEG 200 was decreased, and WVP increased as the total amount of plasticizer added to the films increased. Film strength was improved by the addition of small amount of sodium hydrogen sulfate, succinic anhydride, ascorbic acid and citric acid, whereas TS of films containing $0.5{\sim}2.0%$ of NaCl and $CaCl_2$ were lower than those without the salts. The highest TS (6.3 MPa) was achieved with films containing 0.1% of succinic anhydride.

• Korean Journal of Weed Science
• /
• v.9 no.2
• /
• pp.97-102
• /
• 1989

1. IAA showed no significant growth of root primordia and then lateral root emerged at 2 days after IAA treatment. BA treatment, however, strongly inhibited the formation of root primordia and a few lateral roots, if any, emerged about 5 days after treatment. 2. Treatment of BA and Indol-B on the water retaining ability sampled 1, 3, 5 days after chemical treatment was apparent on the soybean sprouts sampled 5 days after treatment while the difference among the treatments was negligible when sampled 1 and 3 days after treatment. 3. BA stimulated ABA content in the hypocotyl while inhibited ABA content in the root of soybean sprouts. ABA may relate with water retaining ability. 4. Soaking the soybean seeds to several seed disinfectant chemical solution had no effect on the growth and elongation of soybean sprouts. 5. It can be recommended that container of soybean sprouts should be shut tight during growing period except irrigation because the ethylene accumulation in the container may stimulate hypocotyl swelling and inhibit length of soybean sprouts.

• Korean Journal of Organic Agriculture
• /
• v.19 no.1
• /
• pp.65-82
• /
• 2011

In order to evaluate the weed suppressing effect of Solanum viarum Dunal. In this study species diversity in patch of S. viarum and allelopathic effects of the aqueous extracts on S. viarum were investigated. Number of species and species diversity in site close to patch of S. viarum were decreased gradually 1site ($7.7{\pm}2.0,\;1.5{\pm}0.2$), 2site ($5.3{\pm}1.2,\;1.2{\pm}0.2$) and 3site ($4.0{\pm}1.7,\;0.9{\pm}0.1$). And total phenolic compounds of soil in survey area were increased gradually site1 ($0.16{\pm}0.01mg\;g^{-1}$), site2 ($0.17{\pm}0.01mg\;g^{-1}$) and site3 ($0.22{\pm}0.02mg\;g^{-1}$). So the number of species and species diversity (r=-0.692, P<0.05) were negatively correlated with increased total phenolic compounds of soil in the survey area. The relative germination ratio, the mean germination time, the relative elongation ratio, the fresh weight and the dry weight of receptor plants are generally getting decreased while the concentration of the aqueous extracts from S. viarum escalate. But every ratio was various depending on the growing regions, the kind of receptor plants and the treatment of the aqueous extracts. Especially, the radicle by injection of the aqueous extracts concentration of S. viarum was influenced more than the shoot on the same condition. The total phenolic compounds on region of S. viarum was gradually increased in stems (fresh $0.56{\pm}0.02mg\;g^{-1}$, dry $1.58{\pm}0.08mg\;g^{-1}$), roots (fresh $1.77{\pm}0.07mg\;g^{-1}$, dry $2.64{\pm}0.06mg\;g^{-1}$), leaves (fresh $6.01{\pm}0.14mg\;g^{-1}$, dry $7.04{\pm}0.29mg\;g^{-1}$), seeds (fresh $6.21{\pm}0.17mg\;g^{-1}$, dry $9.08{\pm}0.73mg\;g^{-1}$) in order. On the contrary, the negative correlation on germination and growth of receptor plants was shown by total phenolic compounds on the each parts of S. viarum. We think that the aqueous extracts of S. viarum showed allelopathic effects on other plants. Therefore, S. viarum holds the higher competitiveness in plant community in Jeju Island and makes possibility of application as natural herbicide.

• Korean Journal of Medicinal Crop Science
• /
• v.9 no.4
• /
• pp.310-317
• /
• 2001

The regenerated-bulblets placed in liquid free media resulted in good formation of roots and bulblets. On 1/4 MS free medium, roots and bulblets were predominantly induced. The 1/4 MS liquid medium supplemented with plant growth regulators was the best suitable condition for elongation of leaves and roots. Somatic embryos were frequently developed from embryogenic callus in liquid media with 2,4-D 1mg/ l . On free liquid media, the viability of callus reduced. As the salt strength of MS media reduces, the viability of callus reduced significantly. However, Leaves were induced from several callus clumps. When leaves, roots and bulb-scale segments were placed on MS media containing NAA 1mg/ l or 2,4-D 1mg/ l and various sucrose concentration, the best result about the differentiation, growth of leaf and the differentiation of leaf was obtained on MS media added 1.5% sucrose and 2,4-D 1mg/ l, 3% sucrose and NAA 1mg/ l, and 1.5% sucrose and NAA 1mg/ l, respectively. Also the better result differentiation, growth of root and differentiation of bulb was obtained on MS media with 6% sucrose and NAA 1mg/ l. Spermidine promoted the growth of leaf and the differentiation of bulb. However, spermine promoted the differentiation of leaf, the differentiation and the growth of root in MS solid media. On the MS liquid media, both spermine and spermidine stimulated organogenesis from bulb-scale segments. Regenerated plantlets were acclimatizated and grown in greenhouse in vermiculite + perlite (1 : 1 by volume) well. The optimal soil condition of rooting for plantlets regenerated was in peat moss.

• Journal of Food Hygiene and Safety
• /
• v.32 no.5
• /
• pp.434-442
• /
• 2017

The UV light in sunlight breaks down the chemical bonds in a polyolefin polymer through a process called photodegradation, ultimately causing cracking, chalking, colour changes, and loss of physical properties such as impact strength, tensile strength, elongation, and others. UV absorbers are used to prevent or terminate the oxidation of plastics by UV light. They are receptive to UV radiation and dissipate the energy harmlessly as heat. Benzotriazoles and benzophenones are used mainly in polyolefins such as polyethylene and polypropylene. In this study, we have developed a method for the analysis of 12 UV absorbers, which are Uvinul 3000, Cyasorb UV 24, Uvinul 3040, Tinuvin 312 and P, Seesorb 202, Chimassorb 81, Tinuvin 329, 234, 326, 328 and 327, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The UV absorbers in food simulants were determined by reversed-phase high performance liquid chromatograph-ultraviolet detector with 310 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.049~0.370 mg/L), and limits of quantification (0.149~1.120 mg/L). The recoveries of UV absorbers spiked to four food simulants ranged from 70.05% to 110.13%. The developed method would be used as a reliable tool to determine concentrations of the migrated UV absorbers.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.2
• /
• pp.87-95
• /
• 2017

The increase in the frequency of occurrence of abnormal weather could include severe rainfall, which could cause rice submergence during the ripening stage. This experiment was conducted to clarify the effects of submergence during the ripening period on yield and quality of rice. The flooding treatment was conducted at 7 and 14 days after heading. Flooding conditions were created with two conditions, flag leaf exposed and overhead flooding, and each condition was divided into two conditions according to water quality-clear and muddy. Although the yield decrease was more severe at 7 days after heading because of the decrease in the ripening ratio, the head rice ratio was more affected at 14 days after heading because of the increase in the chalky kernel ratio. The maximum quantum yield (Fv/Fm), which indicates the photosynthetic efficiency, did not differ before and after the flooding treatment until flooding continued for 4 days. In addition, stem elongation occurred because of flooding as an avoidance mechanism in japonica rice. This phenomenon was expected to decrease the supply of assimilation products to the spikelet (sink). Overall, it was suggested that additional experiments should be conducted examining the change in the starch synthesis mechanism and transfer of assimilate products resulting from submergence, for development of cultivation techniques corresponding to submergence and breeding of varieties with submergence tolerance characteristics.