• Korean Journal of Environment and Ecology
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• v.17 no.2
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• pp.123-132
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• 2003

This ecological study investigated the vegetation changes of abandoned salt field, 21 plots(1${\times}$lm, 1${\times}$2m) set up by the methods of Braun-Blanquet and Elenberg in a coastal island, Gasado, Jindogun, from July to September,2002. The vascular plants of abandoned salt field in the surveyed site identified 17 families and 48 species. Of these species, halophytes and mesophytes were 20(42%) and 28(58%) species. In addition, the disturbance to this habitat led to the change of halophytes in abandoned sald field, exotic plants was distributed 23 species, which included Dactylis glomerata, Conyza canadensis, Oenothera odorata, Cosmos bipinnatus, etc., in the group of, mesophytes were 20(71%) species, vegetation communities were classified into 3 community types, i.e. the halophyte grassland community(Limonium tetragonum community, Suaeda japonica community, Spergularia marina community), the wetland grassland community(Phragmites communis community, Carex scabrifolia community, Phaceturus latifolius var. angustifolius community), and the mesophyte grassland community(Erigeron bonariensis community, Daucus littoralis var. koreana community). Each communities was described the structual, distribution and changes of the vegetation in the abandoned salt field, the vegetation table and actual vegetation map were prepared.

• Journal of Life Science
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• v.21 no.7
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• pp.969-975
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• 2011

We focused on relationship between phytohormones and AtEXPA3 gene in gravitropic response of A. thaliana. RT-PCR analysis shows that AtEXPA3 was highly expressed in actively developing tissues such as leaf, rosette, root and flower tissues. AtEXPA3 gene expression was enhanced by gravistimulation, BR and IAA. Furthermore, decreased gravitropism was observed when treatment of AVG, an ethylene biosynthetic inhibitor, suggesting that ethylene has a gravistimulating effect itself as well as BRs and IAA. Inhibition of gravitropism in AtEXPA3 RNAi mutant suggests that BR, auxin and ethylene are playing roles as regulators of AtEXPA3. In addition, altered gravitropism in BRs signaling mutant (decreased in bri1-301, bak1, and increased BRI-GFP) indicated that BRs signaling mediated the gravitropism. In conclusion, gravitropic responses of Arabidopsis root resulting from root growth were mediated by increased expression of AtEXPA3 gene, which is stimulated by phytohormones.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.289-300
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• 2009

Flora distribution was surveyed in the newly reclaimed tidal flats in the west coastal area in Korea to understand changes in flora dynamics after reclamation. The surveyed reclaimed tidal flats were the newly reclaimed tidal flat in Hangdam, the mid Kyonggi Bay in 2002, and three reclaimed lands in Seukmun and Daeho, Chungnam, and Hangdam in Kyonggi Bay, of which reclamation years based on embankment were 7, 9 and 18 years, respectively. In the newly reclaimed tidal flat, the dominant flora was Suaeda japonica and other florae were rare, while various halophytes and glycophytes were distributed in the reclaimed lands. On the newly reclaimed tidal flat, four species of halophytic pioneer florae, Salicornia europaea, Suaeda glauca, Suaeda japonica, and Suaeda maritime occurred, and along with age facultative halophyte and glycophyte occurred sequently. On the reclaimed lands, the florae were more complex with various facultative halophyte and glycophyte, so these were predominated rather than pioneer halophyte, while one of pioneer halophyte that Suaeda japonica was not occurred. Increasing of various facultative halophyte and glycophyte, and decreasing of pioneer halophyte indicated that flora changed toward to increase of facultative halophyte and glycophyte by aged after reclamation. On the newly reclaimed tidal flat the ratio of flora species changed rapidly with the invasion of plant. This implied that the flora had begun to change in the early stage of reclamation. Facultative halophyte and glycophyte started to increase on the early stage of reclamation but relative density and frequency of pioneer halophyte was higher than facultative halophyte and glycophyte. According to the investigation up to 3 years after reclamation, pioneer halophyte predominated on it. Although flora changed, there were common representative halophytes among the reclaimed tidal flats: Salicornia europaea, Suaeda maritima, and Suaeda glauca as pioneer halophyte, Aster tripolium, Sonchus brachyotus, and Phragmites communis as facultative halophytes.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.137-142
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• 1995

The acidic amino acids, aspartate and glutamate, which have a negative charge in physiological pH, possess the same transport system as neutral amino acids according to the competitive inhibitory studies with the neutral amino acids. The neutral amino acids cotransported with one H+ per molecule, and one K+efflux per one molecule for charge compensation (Cho,1994), but the acidic amino acids cotransported with two H+ per one molecule, and one K+ efflux per one molecule. The active transport system, which possess the same carrier but cotransported with the different number of H+, reported for the first time. from the results, we can see that one of cotransported H+ protonated at first carboxyl group of pK$_3$ of acidic amino acids, and then as a neutral form cotransported with H+ Therefore, Brassica possess two amino acids transport system for 20 amino acids, namely general - and basic amino acids transport system. The evolutionary meaning of amino acid carriers described with other reported plants.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.280-288
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• 2009

To identify controlling factors for spatial variation of vegetation in reclaimed tidal flats, plant stands were investigated in a newly reclaimed as well as three matured tidal flats, and a natural tidal flat in the midwest coast of Korea. Electrical conductivity of saturated soil extract (ECe) was measured to assess soil salinity. Soil salinity differed significantly among plant stands. Depending on soil salinity, plant species showed different niches: glycophyte predominated low saline spots, halophyte predominated high saline spots. Soil salinity for each plant habitats was in order of as follow: bare soil or plant wilted > mixed pioneer halophyte > pioneer halophyte > mixed with pioneer halophyte and facultative halophyte > mixed facultative halophyte > facultative halophyte > mixed with facultative halophyte and glycophyte > glycophyte > mixed glycophyte stands. These results suggested that plant distribution might have been influenced by spatial edaphic gradient (soil salinity), and thus it could be utilized as an indicator for field soil salinity gradient. Relationship between soil salinity and plant distribution was not different among the aged reclaimed tidal flats, suggesting that the vegetative population might have changed into a similar direction since the reclamation.

• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.324-333
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• 1997

This research was conducted to determine contents of lipids and hydrocarbons for plants distributed in the sourthern region of Korea. The lipid extracts from each plants were purified by solvent fractionation, column chromatography. TLC and analyzed by gas chromatography. As a result, contents netural lipids and phospholipids were the highest in Aleurites fordii and Camellia japonica among the all plants examined. Most of the fatty acids in lipids was palmitic acid, oleic acid and linoleic acid. Content of hydrocarbon was the highest in Fatsia japonica among the all plants examined. Hydrocarbons contained in the plant was mainly more than 16 number of carbons.

• Journal of Life Science
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• v.28 no.1
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• pp.9-16
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• 2018

Light is essential to the growth and development of plants, and it is perceived by phytochromes, which are one of the photoreceptors that regulate physiological responses in plants. Ethylene regulates the dormancy, senescence, growth, and development of organs in plants. This research focused on the interaction of phytochromes and ethylene to control hypocotyl growth and gravitropism using phytochrome mutants of Arabidopsis, phyA, phyB, and phyAB, under three light conditions: red (R) light, farred (FR) light, and white light. The mutant phyAB exhibited the most stimulation of gravitropic response of all three phytochrome mutants and wild type (WT) in all three light conditions. Moreover, phyB in the R light condition showed more negative gravitropism than phyA. However, phyB in the FR light condition showed less curvature than phyA. The hypocotyl growth pattern was similar to the gravitropic response in several light conditions. To explain the mechanism of the regulation of gravitropic response and growth, we measured the ethylene production and activities of in vitro ACS and ACO. Ethylene production was reduced in all the mutants grown in white light in comparison to the WT. Ethylene production increased in the phyA grown in R light and phyB grown in FR light in comparison to the other mutants. The ACS activity coincided with the ethylene production in the phyA and the phyB grown in R light and FR light, respectively. These results suggest that the Pfr form of phyB in R light and the Pr form of phyA in FR light increased ethylene production via increasing ACS activity.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.345-350
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• 1995

Root gravitropism was investigated in the pea (Pisum sativum L.) mutant ageotropum lacking normal gravitropic response. Exogenous ethylene treatment inhibited gravitropic response in the normal (wild type) pea rook, but had no significant effect to restore the unresponsiveness in the mutant Neither inhibitors of ethylene biosynthesis nor antagonists of ethylene action were able to bring about the development of gravioopic curvature in the ageotropum roots. Auxin action seems to be normal since asymmetric application of agar blocks containing auxin to the mutant roots caused normal gravitropic response to occur. Endogenous as well as auxin-induced ethylene production in tissue segments of the mutant root was about equal to that of the wild type. However no appreciable lateral transport of labeled auxin was observed in glavistimulated mutant roots whereas typical auxin asymetry was apparent in the wild type roots under the same conditions. It is concluded that the mutant has a defect in either gravity perception or its transduction, but not in the effector system involving auxin action.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.38-47
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• 1988

To determine the response of soybean cultivars to nitrogen in relation to acidity, nodulation, content of allantoin nitrogen and major chemical compositions of soybean plants were investigated with two cultivars under two levels of soil pH and four levels of nitrogen fertilization in a field and nutri-culture experiments. Nodulation and contents of allantoin nitrogen, total nitrogen, potassium, calcium, magnesium and manganese of soybean plants decreased under acidic condition, but the degree of decrease was smaller in the variety Jangbaegkong compared to the variety Danyeobkong. On the other hand, nodulation, content of allantoin nitrogen and potassium decreased with increased nitrogen fertilization, particulary under pH 7 condition. Nodulation was positively correlated with the content of allantoin nitrogen of soybean plants. The content of total nitrogen of soybean plants increased with increased nitrogen fertilization, and this tendency was remarkable under acidic condition and in the variety Jangbaegkong.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.201-206
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• 1994

The influx of glycine, valine, alanine, and histidine was inhibited by all tested neutral amino acids competitively and the reciprocal inhibitory studies showed the neutral amino acids possess the same transport system as neutral amino acids process to the same catalytic site of one carrier to each other, The molecules of histidine were transported actively as a neutral form through the neutral amino acid transport system but were not transported as a charged form. The Km values of the neutral amino acid transport system have been divided into three different category on basis of the affinity to the carrier, below 0.1mM, etween 0.1ImM-0.5mM and above 0.5mM. The $V_{max}$ was between $3.12{\mu}mole{\cdot}h^{-1}{\cdot}g$ fresh $weight^{-1}\;-\;15.1\;{\mu}mole{\cdot}h^{-1}{\cdot}g$ fresh $weight^{-1}$. Neutral amino acids cotransported with one $H^{+}per$ one molecule and one $K^{+}-efflux$ per one molecule for charge compensation. Histidine cotransported with proton per one molecule, however the movement of cotransported proton can't detectable because of the release of proton from the charged molecules of histidine in the medium.