• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.146-153
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• 2013

This study was conducted to enhance graft-take ratio and quality of grafted tomato seedlings by controlling temperature and humidity during the healing and acclimatization processes. Three temperature levels ($20^{\circ}C$, $23^{\circ}C$, and $26^{\circ}C$) were carried out to determine optimum temperature on four rootstocks. In addition, twelve combinations of three relative humidity levels (70%, 80%, and 90%) and four temperature levels ($17^{\circ}C$, $20^{\circ}C$, $23^{\circ}C$, and $26^{\circ}C$) were set up to evaluate the effect of relative humidity and temperature on the graft-take ratio of grafted seedlings. In the other hand, five relative humidity periods (H0, H1, H2, H3, and H4: 90% relative humidity for first 0, 1, 2, 3 and 10 days and afterwards relative humidity was reduced to 70%, respectively) were examined effect of relative humidity periods on the graft-take and quality of grafted seedlings. The higher graft-take ratios (84.0~87.4%) were showed at $23^{\circ}C$ compared to $20^{\circ}C$ and $26^{\circ}C$ in all rootstocks. Graft-take ratios decreased and number of diseased plants increased at high temperature. The graft-take ratios increased with increasing relative humidity in all temperature levels on the $3^{rd}$ and $7^{th}$ day after grafting. However, increasing relative humidity significantly increased percent of diseased plants. The graft-take ratio reduced at ($26^{\circ}C$) and ($17^{\circ}C$) temperature under all relative humidity conditions. The graft-take ratio increased with increasing period of 90% relative humidity. Maximum graft-take ratios were observed in H2 and H3 treatments. Graft-take ratio decreased with increasing 90% relative humidity for 10 days (H4). Diseased plants had not been found in H0, H1, H2, and H3 treatments. Seedling quality was improved through increasing fresh and dry weight of root, compactness, and root morphology of tomato seedlings in H2 and H3 treatments. Therefore, high relative humidity (90%) for first 2 or 3 days and afterwards reduced low relative humidity (70%) at $23^{\circ}C$ condition during healing and acclimatization promoted the graft-take and quality of grafted tomato seedlings.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.62-70
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• 1994

This study was conducted to find out if there are some differences in germination, growth and morphological characteristics between rice(Oryza saliva) and barnyardgrass(Echinochloa crus-galli) under various cropping patterns and to abtain the fundamental information on weed control method in direct seeded rice. Rice was broadcast on soil-surface(Broadcast rice), drill seeded in soil(Drilled rice) and barnyardgrass was drill seeded in soil(Barnyardgrass) under dry(Dry condition) and water direct seeded condition(Water condition). Also rice was transplanted with 8-day seedlings(8 -day-old seedling) and 25-day seedlings(25-*day-old seedling) under transplanting condition(Transplanting condition) At 1, 2, 3, 5, 7, 10, 15 and 20 days after seeding or transplanting(DAS/T), plants were harvested to examine their germination, growth and morphology. The major results were as follows ; Until 5 DAS/T growth of rice and barnyardgrass were well established under dry condition but under water condition growth of shoots was mainly elongated. At 20 DAS/T barnyardgrass had greater plant height and shoot fresh weight than rice under direct seeded condition, while plant height and shoot fresh weight of rice was greater than those of barnyardgrass under transplanting condition. Root length of barnyardgrass was greater under the dry, drilled, direct seeded conditions than that of rice under the water, broadcast, transplanting condition, respectively. And root fresh weight of rice under direct seeded condition was similar to that of barnyardgrass but that of rice under transplanting condition was significantly greater than that of barnyardgrass. Barnyardgrass only formed mesocotyls and its length increased with increased depth of seeding. Leaf stage and leaf area of barnyardgrass was greater under the dry, drilled than those of rice under water, broadcast conditions, respectively, while those of rice was greater than those of barnyardgrass under transplanting condition. Chlorophyll contents were higher in barnyardgrass, dry direct seeded rice, transplanted rice, water direct seeded rice in descending order.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.1-6
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• 1986

The growth, development, and morphological characteristics of Echinochtoa colons (L.) Link were determined through one life cycle. E. colons emerged 2 to 3 days after seeding (DAS) and reached the two leaf stage by 8 DAS. During the early growth stages, root length was greater than plant height, but the relationship was reversed from 4 weeks after seeding (WAS). Tillering started from the third leaf of the main culm as the sixth leaf on the main calm emerged. The unfolding of the leaves and tillering followed a regular pattern during the vegetative growth period. This resulted in the production of 19 tillers (5 primary, 12 secondary, 1 tertiary, and I nodal) at the 14-leaf stage. Shoot-root weight ratio was highest just before panicle initiation. The second spike from the top of the panicle was the shortest and produced the fewest seeds. Thereafter, spike length and the number of seeds per spike generally increased, the lower the position of the spike on the panicle. Seeds on the lower spikes weighed less and had lower germination ability than those from the upper spikes. Adventitious roots arose from the leaf sheath bases of a flowering stalk. The ability to produce adventitious roots was greater in a younger stalls than in an older stalk.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.43-49
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• 2014

This study was designed to determine the effect of red LEDs during healing and acclimatization process on the survival rate and quality of grafted tomato seedlings. Red LEDs and no light (darkness) were used for treating three rootstock cultivars, which are 'B-Blocking', 'Kanbarune', 'High-power' in healing room. Results showed that survival rates of grafted seedlings in red LEDs were higher than those in no light treatment. Significant variation on survival rates of rootstock cultivars was observed in no light treatment but there was not significant variation in red LEDs treatment. Light treatment also reduced the percentage of infected plants, except for the 'Kanbarune' cultivar. Seedling quality in red LEDs was better than that in no light treatment by improving growth parameters such as plant height, leaf length, leaf width, leaf area, fresh and dry weight of shoot and root. Light treatments and rootstock cultivars did not affect number of leaves, leaf chlorophyll value and T/R ratio of seedlings, but seedlings in red LEDs were significantly more compact than those in no light treatment. Moreover, the root morphology of seedlings such as total root surface area, total root length, and number of toot tips in red LEDs was also greater than that in no light treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.199-202
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• 2000

The leaf color varies with the contents of pigments, especially chlorophylls and carotenoids. Teichung 65 (T.65), a japonica rice, with pgl(pale-green leaf) gene exhibits pale green color on the whole plant from seedling to harvest. This study conducted to evaluate the agronomic characters and examine the chloroplasts of 'pgl' plants in parents and BC$_1$F$_2$ of T.65(pgl) xSuweon ${345}^2$. The average grain yield of pale-green-leaf individuals in F$_2$ was the same as T.65(pgl) but that of green-leaf individuals was much higher than that of Suweon 345. The contents of chlorophyll a(Ca), chlorophyll b(Cb) and total chlorophyll content(Ct) of T.65(pgl) in flag leaf were lower than those of Suweon 345, but the Ca/Cb ratio of T.65(pgl) was higher than that of Suweon 345 during from 15 days after heading (DAH) to 60 DAH. The SPAD value of T.65(pgl) in flag leaf was lower than that of Suweon 345, but that in the second and the third leaves was similar to that of Suweon 345. The SPAD value of pale-green-leaf individual group was lower than that of green individual group in upper three leaves. The structural difference of chloroplasts in flag leaf between T.65(pgl) and Suweon 345 through TEM at 20 DAH was not detected, but the number of osmium granules in chloroplast of T.65(pgl) were higher than that of Suweon 345.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.51-56
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• 2015

The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.

• Journal of Bio-Environment Control
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• v.24 no.1
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• pp.13-20
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• 2015

This study was conducted to evaluate influence of short-term application of abscisic acid (ABA) in nutrient solution on growth and drought tolerance of tomato seedlings. The treatments included four ABA concentrations (0.5, 1, 2, $3mg{\cdot}L^{-1}$) and control (non-treatment) were applied to the nutrient solution in a hydroponic system. On the $5^{th}$ and $10^{th}$ day after growing in the nutrient solution containing ABA, seedlings were transferred to -5 bars of PEG-8000 in a growth chamber to induce water stress. Except for stem diameter and fresh and dry weight of root, there were no statistical differences in other growth parameters among control, 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments. Seedlings growths were strongly inhibited in nutrient solution containing 2 and $3mg{\cdot}L^{-1}$ of ABA. The root growth such as fresh and dry weigh of root, total root surface area, and average root diameter was slightly enhanced in $1mg{\cdot}L^{-1}$ of ABA treatment. The elevation of ABA concentrations in nutrient solution resulted in the decrease in transpiration rate and increase in stomatal diffusive resistance and leaf temperature of tomato seedlings. The initiations of seedling wilting after treating in -5 bars of PEG were delayed from 10 hrs in control to 30 hrs in ABA applied treatments. Additionally, the high percentages of recovered seedlings were observed in 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments after re-irrigation. Therefore, short-term application of $1mg{\cdot}L^{-1}$ of ABA in the nutrient solution stimulated the root growth and drought tolerance of tomato seedlings by delaying the start time of wilting point and enhancing the recovery after re-irrigation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.1
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• pp.1-12
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• 2018

This study sought to analyze changes in the vegetation structure and species diversity indices in the Abies koreana forest in the Yeongsil area of Hallasan Mountain and establish basic data for Long-Term Ecological Research (LTER). The results show that the number of woody plants per 1ha has increased by 804 (45.1%) from 1,781 to 2,585 individual plants, whereas the number of live A. koreana did not change much with 796 individual plants. The number of dead tree plants, however, jumped by 807 (82.2%) from 982 to 1,789 plants. With other tree species, the number of live individual plants increased by 807 (82.2%) from 982 to 1,789 plants, whereas the number of dead plants increased by 31 from 10 to 41 individual plants. Results of the average importance index analysis show that the number of A. koreana decreased, while the number of Weigela subsessilis, Rhododendron yedoense for. poukhanense, and Magnolia sieboldii increased. The species diversity index increased by 6.7% as per the maximum level in the upper layer and by 7.2% in the lower layer, respectively. Results of the stem morphology analysis show that the number of AS type was highest with 700 individual plants among A. koreana, while their distribution by type shifted from AS>AL>DS>DB to AS>DS>AL>DB. As for other species, the AS type was most abundant with 1,580 individual plants, while their distribution by type shifted from AL>AS>AF>AB to AS>AL>AB>AD. The number of newly sprouted tree plants has increased from 420 in 2014 to 453 in 2016. Of the individual plants that were alive in 2014, 23 were found dead and 33 individual plants younger than 3 years old have been newly added to the group. The number of deaths after 2014 was highest among the 2 years olds, whereas the number of 2 years olds that sprouted in 2014 was highest among the newly sprouted tree plant group. In the A. koreana forest in Yeongsil, the density of other species was rising rapidly with the exception of the dead and live A. koreana. The occurrence of new tree plants is decreasing rapidly, thereby confirming the rapid change in the area's vegetation structure. Therefore, there is a need for continuous long-term ecological research to monitor vegetation change. It can also be used as a basic data for efficient restoration research.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.358-364
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• 2011

To examine the possibility of natural regeneration of six Acer species in broadleaved mixed forest in Korean peninsula, samples of six Acer species' samaras were collected at several seed sources from September to October 2009 and 2010, and seed morphological characteristics and viability were studied using cutting method. Inflorescense type of Acer mandshuricum(AM), A. pseudosieboldianum(APS) and A. palmatum(AP) is corymb, that of A. pictum subsp. mono(APSM) and A. okamotoanum(AO) is flat-topped panicle, and that of A. ukurunduense(AU) is raceme. Number of seed-set per inflorescense proves the highest value 38.5 sets in AU and the lowest value 2.4 sets in APS. Diameter of the seeds proves highest value 13.5mm in AO, and the lowest value 4.7mm in APS. Angles between the wings proves the highest values $130.05^{\circ}$ in APS, and the lowest value $48.60^{\circ}$ in AU. Air dry weight of 20 seed-sets proves highest value 3,900mg, in AO, and the lowest value 404mg in AU. Viable seed ratio of AP proves 50%, and that of AU does 43.2%. Those of other four species ranges 8.6~22.2%. Considering postdispersal seed predators and disturbance of litter, viable seeds of APSM, AO, AM, and APS supplied in the natural forest in Korea might be insufficient for seedling establishment. This study showed that sound viable seed supply might be key factors of natural regeneration of major Acer species in Korea. The openings made by insect pests were observed on the seed-coat of APSM, AM, AU, and APS samara, and Bradybatus sharpi were observed in the samaras of APSM and AO. Further study on the seed insect fauna, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

• 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.