• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.463-475
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• 2018

Salinity and extreme temperature stresses affect growth and productivity of crops negatively. Beneficial bacteria, including plant growth-promoting rhizobacteria (PGPR) induce growth promotion and tolerance of plants under abiotic stress conditions. In the present study, 20 strains were selected from 1944 isolated bacteria based on three plant growth-promoting (PGP) traits-aminocyclopropane-1-carboxylate deaminase activity, phosphate solubilization, indole-3-acetic acid production, and growth ability under salinity and extreme temperature stress conditions. Seven among the 20 strains were selected based on growth-promoting effects on plants under saline or temperature stresses in tomato plants. It was expected that the seven strains could induce tolerance of tomato plants under salinity or extreme temperature stresses, which implies that these seven strains can act as potential inducers of multiple stresses tolerance in tomato plants.

• Korean Journal of Plant Resources
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• v.18 no.1
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• pp.22-31
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• 2005

To evaluate growth adaptation of the soybean in paddy field, five soybean cultivars were grown in Yeoncheon with two cultivating methods, level row and high ridge. Growth characters of the top plants, such as stem lengths, numbers of branches, diameters of stem, were higher under high ridge than under level row. However, the differences among the cultivars were bigger than those between the cultivation methods in each cultivar. Comparing the growth of top plants, dry matters in level row were higher than those in high ridge in V5 stage, however, via verses as growth progressed with significant differences among the cultivars. Roots were more developed under high ridge than those under level row during whole growth stages, such as V5, R2, and R5 stages. T/R ratio in level row was significantly higher than that in high ridge with significant differences among the cultivars.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.117-117
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• 2022

표고(Lentinula edodes (Berk.))는 담자균강 주름버섯목 느타리과 잣버섯속에 속하는 식용버섯으로 봄에서 가을에 걸쳐 주로 재배하며, 예부터 식용 및 약용으로 널리 이용되어져 왔다. 우리나라를 비롯하여 일본, 중국 등의 동남아시아 지역뿐만 아니라 최근에는 미국, 캐나다 및 네덜란드 등의 서구 나라에서도 관심이 높으며, 전 세계적으로 중요한 식용 버섯으로써 주목을 받고 있다. 표고는 혈중 콜레스테롤 수준의 감소, 항당뇨, 혈압조절, 면역증강, 간 보호 및 비만 억제 등의 다양한 생리활성이 밝혀져 있어 현대인의 식생활에서 수요가 더욱 증가되고 있는 추세에 있다. 버섯의 생육은 크게 균사의 생장과 자실체의 생육으로 구분되는데, 표고 균사의 배양 기간이 86~123일 정도 소요되며, 자실체의 생육 기간은 10~20일 정도로, 균사의 배양 기간이 훨씬 긴 것으로 나타났다. 버섯의 생육 단계에서 영양, 생식, 생장은 모두 수분으로부터 비롯되며, 생육 조건, 조도, 환기 정도 등에 따라 버섯의 품질은 상당한 차이를 보일 수 있다. 일반적으로 봄에 수확한 표고는 대가 짧고 단단하며 감칠맛이 풍부하며, 가을에 수확한 표고는 대가 길고 육질이 부드럽고 비교적 강수량이 높아 수분함량이 높은 것으로 알려져 있다. 이러한 현상은 표고의 수확 시기에 따라 기후, 온도, 강수량 등의 차이가 이화학적 특성에 큰 영향을 미치는 것으로 생각되어, 본 연구에서는 봄과 가을에 각각 표고를 수확하여 이화학적 특성 및 기능성성분을 비교하였다. 분석결과 가을에 수확한 표고가 봄에 수확한 표고에 비해 수분, β-glucan, ergosterol 그리고 ergothioneine 함량이 유의적으로 높게 나타나, 소재 개발 시에 경제적 경쟁력을 고려했을 때 가을에 수확한 표고 활용이 유리할 것으로 고려된다.

• Applied Microscopy
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• v.42 no.2
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• pp.95-103
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• 2012

The cell surface sculpture of the plant epidermis has received great interest recently. It has also been an active area of research, as the biological microstructures of the surface, such as papillae and waxes, exhibit several unique properties, including self-cleaning character; namely the "Lotus effect" first described in the leaves of the lotus, Nelumbo nucifera. The Lotus effect is the phenomenon in which the super-hydrophobic and water-repellent nature of lotus leaves allow water drops to run off easily on the surface in a rolling and sliding motion thereby facilitating the removal of dirt particles. It is well-known that surface roughness on the micro- and nanoscale is a primary characteristic allowing for the Lotus effect. This effect is common among plants and is of great technological importance, since it can be applied industrially in numerous fields. In the present study, Nelumbo nucifera leaf and stem epidermal surfaces have been examined with a focus on the features of papillae and wax crystalloids. Both young and mature Nelumbo nucifera leaf epidermis demonstrated the Lotus effect on their entire epidermal surface. The central area of the upper epidermis, in particular, formed extremely papillose surfaces, with an additional wax layer, enabling greater water repellency. Despite the presence of wax crystalloids, epidermal surfaces of the lower leaf and stem lacking papillae, were much more easily wetted.

• Research in Plant Disease
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• v.30 no.2
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• pp.131-138
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• 2024

The effects of five fungicides on the spore growth phase of Alternaria dauci, which causes carrot leaf blight, were tested using the spore viability assay (SVA) and agar dilution method (ADM). The average EC₅₀ values for chlorothalonil against seven isolates of A. dauci examined by SVA and ADM were 14.21 ㎍/ml and more than 100 ㎍/ml. Dithianon and folpet also had lower EC₅₀ values in SVA than in ADM, while iminoctadine trisalbesilate had lower EC₅₀ value in ADM. For fluazinam, the EC₅₀ values of SVA and ADM were 1.63 and 2.40 ㎍/ml, respectively. As EC₅₀ values of five fungicides according to the spore growth phase of A. dauci KACC 42997, the efficacy of each fungicide as chlorothalonil, dithianon, and folpet decreased when treated after spore germination rather than when treated with spores before germination. However, iminoctadine tris-albesilate was more effective when treated after spores germinated than when treated before treatment. The excellent effect of fluazinam on the pathogen was maintained until A. dauci KACC 42997 was cultured in potato dextrose broth for 6 hr and the germ tube grew beyond the size of the spore. However, when treated with iminoctadine tris-albesilate and fluazinam after culturing for 12 hr, as the EC₅₀ values of the two fungicides increased to 8.87 and 20.65 ㎍/ml, their efficacies decreased. The results of this study show that the treatment time of the fungicide should be determined by considering the effect of the fungicide on the spore growth phase of pathogens.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.229-235
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• 2007

Artificial seeds were produced by encapsulation of somatic embryos of Kalopanax septemlobus and investigated the effects of alginic acid concentration, size of somatic embryos, additives in capsules and nursery seedbeds for germination. The most suitable concentration of alginic acid was 3% for germination of encapsulated seeds. Germination was suppressed at higher concentration more than 3% alginic acid. For germination of artificial seeds, 1/2 MS medium with 0.02% activated charcoal was effective. There was no significant differences on the germination among the different size of somatic embryos. Additives in hydrated capsule was very important for germination and post-germinative growth of artificial seeds. Germination was severly inhibited in hydrated capsule containing only distilled water. Both sucrose and MS medium addition in hydrate capsule was effective for germination of artificial seeds. When artificial seeds were transferred to soilbed, germination rate was high in perlite containing 3% sucrose but very low in perlite with only water. These results indicate that nursery additives in both hydrate capsules and soilbeds was important for germination of artificial seeds in Kalopanax septemlobus.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.309-313
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• 2000

To investigate the effects of different UV-B levels on growth and biochemical defense response in plants, cucumber plants were subjected to three levels of biologically effective ultraviolet-B $(UV-B_{BE})$ radiation [daily dose: 0.03 (No), 6.40 (Low) and $11.30\;(High)\;kJ{\cdot}m^{-2}$, $UV-B_{BE}$] in the growth chambers for 3 weeks during the early growth period. Enhanced UV-B radiation drastically decreased both dry weight and leaf area of cucumber. With increasing UV-B intensity, chlorophyll content was decreased, however the level of malondialdehyde was highly increased linearly. Total contents of ascorbic acid and glutathione were tended to increase by UV-B, while the ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were significantly increased with increasing UV-B intensity in cucumber. All the enzyme activities investigated (superoxide dismutase, ascorbate peroxidase, dehydroascorbate reductase, guaiacol peroxidase etc.) in cucumber were increased by the UV-B enhancement. These results suggested that enhanced UV-B irradiation caused photooxidative stress in cucumber plant and resulted in significant reduction in plant growth. Biochemical protection responses might be activated to prevent the leaves from damaging effects of oxidative stress generated by UV-B irradiation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.51-60
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• 2003

Rice, which occupies about 60% of the farmland in Korea, is a staple crop in Asia. It not only absorbs $CO_2$ from the atmosphere, but also emits carbon in a form of CH$_4$. It has a potential role in the global budget of greenhouse gases because of its relative contributions of carbon absorption and emission associated with changing hydrologic cycle. To better understand its current and future role, seasonal variations of energy and $CO_2$ exchange in this critical ecosystem need to be quantified. The purpose of this study was to measure, document and understand the exchange of energy and $CO_2$ in a typical rice paddy in Korea throughout the whole growing season. Since late April of 2002, we have conducted measurements of energy and $CO_2$ exchange in a rural rice paddy at Hari site, one of the Korea regional network of tower flux measurement (KoFlux). After the quality control and gap-filling, the observed fluxes were analyzed in the context of micrometeorology and biophysics. $CO_2$ and energy exchanges varied significantly with land cover changes (e.g., plant growth stages), in addition to changes in weather and climate conditions. This study, reporting first direct measurement of energy and $CO_2$ exchange over a rice paddy in Korea, would serve as a useful database as one of the reference sites in AsiaFlux and FLUXNET.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.486-494
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• 2021

Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) is sensitive to low temperature and shows retarded growth under 10℃. Although early transplanting guarantees higher returns, it requires cost and labor to maintain the appropriate temperature for plant growth. Therefore, cultivars tolerant to chilling stress is necessary to reduce the cost and labor requirements. The purpose of this study is to analyze data on plant growth and fruit enlargement under continuous chilling night temperature to develop new cultivars tolerant to chilling temperature. Two cultivars expected to have chilling tolerance and another cultivar sensitive to chilling temperature were grown in greenhouses with chilling and optimal night temperature conditions. In the early growth stage after transplanting, the cultivars expected to have chilling tolerance showed better vine length, fresh weight and dry weight. However, one of the tolerant cultivars showed significantly lower vine length, leaf length and width, and petiole length than the sensitive cultivar during pollination period and later growth stage, showing genotype specific responses. The fruit length, width, and weight were also significantly lower in the tolerant cultivar. The fruit set ratio was significantly higher in the chilling sensitive cultivar than the two tolerant cultivars. These results suggest that the present chilling tolerant cultivars in watermelon were selected based on their performance in the early growth stage, and further studies on chilling tolerance in different growth and development stages are required to develop cultivars adapted to various forcing cultivation systems.

• Journal of Life Science
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• v.24 no.12
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• pp.1364-1370
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• 2014

Ascorbic acid (AA) is a multifunctional metabolite in plants that is essential for plant development and growth. We examined the effect of AA, an antioxidant, on the gravitropic response of primary roots in maize. The application of $10^{-3}$ M AA to the elongation zone did not affect the gravitropic response and slightly inhibited the root growth. However, treatment with both $10^{-5}$ M and $10^{-3}$ M AA at the root tip increased the gravitropic response and inhibited root growth. Differences in indole-3- acetic acid (IAA) activity between the upper and lower hemispheres of the root resulted in differential elongation along the horizontal root. Roots are extremely sensitive to IAA, and increasing the amount of IAA in the lower hemisphere of the root inhibited elongation. Therefore, we examined the effect of IAA in the presence of AA. The inhibitory effect of AA on the gravitropic response was greater in combination with IAA. To understand the role of AA in the regulation of root growth and the gravitropic response, we measured ethylene production in the presence of AA in the primary roots of maize. AA stimulated ethylene production via the activation of the 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene, which regulates the conversion of ACC to ethylene. These results suggest that AA alters the gravitropic response of maize roots through modification of the action of ethylene.