• Applied Microscopy
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• v.30 no.2
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• pp.233-240
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• 2000

Aspects of structural differentiation of the free -floating hydrophyte, Spirodela polyrhira, has been investigated. The hydrophyte exhibited highly reduced structures having only fronds, connective stalks, and roots as a mature plant. The fronds were major photosynthetic and vegetatively reproducing organ during the growth. Daughter fronds which developed early in the mother frond were also chlorenchymatous, but they remained within foliage sheaths of the mother frond before separation from connecting stalks. Although the stalks and roots originated from the same meristematic region of the frond, they exhibited the distinct polarity showing former lateral growth and latter axial growth. Air chambers were formed only in the fronds and roots. Cellular components were scattered throughout the diffuse cytoplasm in most of the actively growing stalk cells. Root cells protected by the root cap demonstrated relatively complex organization, showing dense cytoplasm with Golgi, rER, mitochondria, and chloroplasts in the cortical cells. Cells in the root cap were highly vacuolated within the peripheral cytoplasm. Such reduction and differentiation of the plant body in Spirodela polyrhiza most effectively contributes to the better adaptation of smaller plants to superficial aquatic environments, while also enabling the rapid growth.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.836-841
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• 2012

Distributions and growth of submerged plants with water level were investigated in a flood control reservoir around Dongbok Lake. In adddition, the total amount of biomass and uptakes of plants per unit area ($m^2$) in the flood control reservoir were investigated. The total vegetation area was $156,871m^2$ in the Dongbok flood control reservoir ($209,160m^2$) before flooding. By July 11, the Dongbok flood control reservoir was flooded during rainy season except for upper area. Dominant plants were CRXDM (Carex dimorpholepis Steud), ECHCF (Echinochloa crusgalli), POLHY (Polygonum hydropiper L) and BROTE (Bromus tectorum L) which occupied 75% of the flood control reservoir. The total amounts of organic matter uptakes per unit area ($m^2$) with distribution rates by CRXDM, ECHCF, POLHY and BROTE under different submerged plants were 65.5, 6.8, 7.0 and 13.0%, respectively. The total amount of nitrogen uptakes per unit area ($m^2$) with distribution rates at different submerged plants were in the order of CRXDM ($1.30g\;m^{-2}$) > POLHY ($0.34g\;m^{-2}$) > BROTE ($0.30g\;m^{-2}$) > ECHCF ($0.25g\;m^{-2}$). The total amounts of phosphorus uptakes per unit area ($m^2$) with distribution rates at different submerged plants were great in the order of CRXDM (51.8%) > BROTE (17.7%) > POLHY (10.3%) > ECHCF (9.6%). Thus, the results of this study suggest that O.M, T-N and T-P by submerged plants in Dongbok Lake were strongly influenced at water quality in flood control reservoir.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.137-141
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• 2013

Flavonoids have various biological activities; however, their cellular uptake mechanism is beginning to be understood only recently. This review focuses on cellular flavonoids transport mechanisms in both plants and animals. In plants, flavonoids exist in various cellular compartments, providing a specialized transport system. Newly synthesized flavonoids can be transported from the endoplasmic reticulum to the vacuoles or extracellular space via cellular trafficking pathway. Among membrane transporters, ATP binding cassette, multidrug and toxic extrusion, bilitranslocase homologue transporters play roles in both the influx and efflux of cellular flavonoids across the cell membrane. In recent years, extensive researches have provided a better understanding on the cellular flavonoid transport in mammalian cells. Bilitranslocase transports flavonoids in various tissues, including the liver, intestine and kidneys. However, other transport mechanisms are largely unknown and thus, further investigation should provide detailed mechanisms, which can potentially lead to an improved bioavailability and cellular function of flavonoids in humans.

• Research in Plant Disease
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• v.21 no.4
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• pp.321-325
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• 2015

A rapid and simple RT-PCR diagnosis method for detection of Rice stripe virus (RSV), one of major virus infecting rice, was developed using porous ceramic cubes in this study. The porous ceramic cube can rapidly absorb biological molecules such as small-sized proteins and nucleic acid fragments into its pores. We examined whether this ability of porous ceramic cubes could be applied for isolating viral nucleic acids or particles from the RSV- infected plant tissues. In this study, we found that the porous ceramic cube was capable of absorbing a detection level of viruses from the rice tissues infected with RSV and established RT-PCR-based RNA diagnosis method using porous ceramic cubes.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.925-927
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• 2012

On-site diagnosis applied to soil having a symptom of yellowing and whitening in cucumber leaf and stem. Soil pH determined 4.2 by methods of on-site analysis and 4.5 by soil test analysis. High aluminum in soil solution extracted with water saturation was detected. Leaf and stem tissue were abundant in Al content but not in Ca. Also, N content of leaf and stem was low compared to normal N ranges. This symptom of cucumber assumed to be from the Al and nitrous acid gas toxicity by low soil pH and Eh. Conclusionally, symptom in leaf and stem of cucumber was alleviated and cucumber normally recovered during cultivation period by applying calcium hydroxide solution to correct soil pH up to 6.5. These results showed that low soil pH resulted in aluminum toxicity and N deficiency to plant growth in on-site farming.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.233-238
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• 2003

The effect of phosphate solubilizing microbes (PSM) on plant P uptake and growth in rock phosphate applied soil was tested under a greenhouse condition. Tobacco plants were grown in nonsterilized soil inoculated with Penicillium oxalicum CBPS-3F-Tsa with or without rock phosphate application as P fertilizer. Phosphorus concentration in tobacco plants was increased by the application of rock phosphate, while inoculation of soil with fungi further significantly increased P concentration in tobacco plants compared with the noninoculated treatments. Phosphorus uptake by tobacco plants was also increased by the application of rock phosphate and PSM inoculation, and the significant comparison has been made with single rock phosphate treatment. Growth of tobacco plant was also significantly increased in the treatments receiving rock phosphate, while the combined application of rock phosphate and PSM further increased plant growth. It was concluded that the positive effect of PSM inoculation on plant growth was closely related in plant P content and uptake. These results suggest that Penicillium oxalicum CBPS-3F-Tsa could solubilize insoluble soil phosphates and rock phosphate which can promote growth and P uptake of tobacco plants.

• Journal of Mushroom
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• v.18 no.1
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• pp.1-9
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• 2020

Mycorrhiza refers to the association between a plant and a fungus colonizing the cortical tissue of the plant's roots during periods of active plant growth. The benefits afforded by plants from mycorrhizal symbioses can be characterized either agronomically, based on increased growth and yield, or ecologically, based on improved fitness (i.e., reproductive ability). In either case, the benefit accrues primarily because mycorrhizal fungi form a critical linkage between plant roots and the soil. The soilborne or extramatrical hyphae take up nutrients from the soil solution and transport them to the root. This mycorrhizae-mediated mechanism increases the effective absorptive surface area of the plant. There are seven major types of mycorrhizae along with mycoheterotrophy: endomycorrhizae (arbuscular mycorrhizae, AM), ectomycorrhizae (EM), ectendomycorrhizae, monotropoid, arbutoid, orchid, and ericoid. Endomycorrhizal fungi form arbuscules or highly branched structures within root cortical cells, giving rise to arbuscular mycorrhiza, which may produce extensive extramatrical hyphae and significantly increase phosphorus inflow rates in the plants they colonize. Ectomycorrhizal fungi may produce large quantities of hyphae on the root and in the soil; these hyphae play a role in absorption and translocation of inorganic nutrients and water, and also release nutrients from litter layers by producing enzymes involved in mineralization of organic matters. Over 4,000 fungal species, primarily belonging to Basidiomycotina and to a lesser extent Ascomycotina, are able to form ectomycorrhizae. Many of these fungi produce various mushrooms on the forest floor that are traded at a high price. In this paper, we discuss the benefits, nutrient cycles, and artificial cultivation of mycorrhizae in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.17-21
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• 1970

To determine the effects of the silicate and the phosphate on the rice seedlings, 200 grams dry soil of the paddy field taken in the petri dish of 15cm diameter were treated with three levels of silicate(wollastonite) and phosphate. And the same amounts of nitrogen and potash were added constantly to each treated petridish. 100 grains of rice of which variety is Nongrim 25 were sown on each treated petridish simultaneously. After five times continuous culture, the rice plants and the soil were analyzed chemically and the results obtained are summarized as follows: 1. Dry matter weight of the rice seedlings was significantly increased to the increased phosphate absorption, on the other hand that was decreased when the silica absorption was increased. 2. The higher the available phosphate content in the soil after the experiments, the lower the silica content as well as absorption by the plant, and the $SiO_2/P_2O_5$ ratio in the plant was significantly decreased. 3. By the wollastonite application, the available silica, the exchangeable calcium in the soil after the experiment, and the silica content as well as silica absorption and $SiO_2/P_2O_5$ ratio in the rice plant was significantly increased. 4. Higher correlation coefficient was obtained between the exchangeable calcium amount and the silica content or silica/phosphate ratio in the rice plant than the available silica content in soil itself. 5. It is possible to control the silica/phosphate ratio in plant by the control of the silica/phosphate ratio in soil. 6. The relation between the silica/phosphate ratio in plant (y) and the available silica/phosphate ratio in soil (x) was $y=0.665+1.420x-0.0825x^2$ and the goodness of fit(r) was 82%.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.1-12
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• 1995

These researches have been conducted to obtain the basic information of the effects of paraquat on plant species and to screen the plant species showing specific responses to paraquat. Paraquat resistance related to ecotype and overwintering capacity. Perennial and biennial species showed higher resistance than annual species. In a family, most species showed higher resistance were overwintering species. Lamiaceae, Brassicaceae, and Caryophyllaceae were tolerant to paraquat, whereas Poaceae and Asteraceae were sensitive. Especially Mosla dianthera of Lamiaceae, Hemistepta lyrata and Aster pilosus of Asteraceae, and Paspalum thunbergii of Poaceae showed higher tolerance than others. The response patterns of plant species on germination stage were different to those on vegetative stage. Germination of Amarathus lividus, Arabis glabra, and Bidens frondosa was not inhibited by paraquat. But their seedling growth were highly inhibited.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.280-291
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• 2007

Much research has been conducted in the field of phytoremediation since the discovery of the range of plants known as hyperaccumulators. Research has focused simultaneously on elucidating the mechanism of metal(loid) accumulation and development of practical techniques to enhance accumulation efficiency. To date, it is generally understood that there are five specific mechanisms employed by hyperaccumulating plant species that are either not or under utilized by non-hyperaccumulators. These include 1) enhanced metal(loid)s uptake through the root cell, 2) enhanced translocation in plant tissue, 3) detoxification and sequestration, 4) enhanced metal availability in soil:root interface, and 5) active root foraging toward metal(loid) enriched soils. Among these mechanisms, understanding of the plant-root effect on metal(loid) dynamics and subsequent plant uptake is vital to overcome the inherit limitation of phytoremediation caused by low metal(loid) solubility in soils. Plant roots can influence the soil chemistry in the rhizosphere through changes in pH and exudation of organic compounds such as low-molecular-weight organic acids (LMWOAs) which consequently change metal(loid) solubility. The decrease in soil pH by plant release of $H^+$ results in increased metal solubility. Elevated levels of organic compounds in response to high metal soil concentrations by plant exudation may also increases metal concentration in soil solution through formation of organometallic complexes.