• Journal of Life Science
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• v.16 no.4
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• pp.699-703
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• 2006

Maize (Zea mays L.) is a monoecious plant, which separates male (tassel) and female (ear) floret that evolved into increasing heterogeneity. In each floret, male or female, bears both one pistil and three stamens primodia before diverged to unisexual state. When diverged to tassel, pistil cell death occurs in the pistil primodium, which is mediated by TASSELSEED genes. In contrast, cell protection occurs in the ear pistil from TASSELSEED-mediated cell death, which is mediated by SILKLESS1 gene. On the other hand, cell cycle arrest occurred for a long time in the ear stamens and then the stamens eventually dye. The cell cycle regulating genes such as CYCLIN B and WEE1 are involved in this process. Furthermore, the temporal and spatial regulation of gibberellin biosynthesis may cause cell cycle block in arresting stamen cells. This review describes the cell death, cell protection, and cell cycle arrest mechanism during maize sex determination process at the molecular, cellular and developmental biology, and genetic levels.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1145-1148
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• 2002

Melatonin, which is a hormone secreted from pineal gland of brain and known to prevent oxidative damages of various tissues, was analyzed in 26 domestic edible plants. For the preparation of melatonin fraction, 50% ethanol extract prepared from lyophilized plant powder was filtered and applied on TLC plate. Melatonin position on TLC developed with acetone was identified by fluorescence light and extracted with methanol. This methanolic fraction was injected into HPLC comprising ODS-A column, fluorescence detector, and mobile phase consisting of a mixture (30 : 70, v/v) of 70% ammonium acetate and methanol at a flow rate of 1.0 mL/min. Melatonin was identified at the retention time of 17 min. Results revealed that celery, leek, broccoli, and cauliflower had higher melatonin contents than others.

• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.75-82
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• 1998

Tritium concentration in the atmosphere during HTO exposure was different between two experiments due to different velocity of HTO evaporation. Assimilation rate of the rice plant was considered to be higher than that of Chinese cabbage The uptake of atmospheric HTO into tissue free water tritium(TFWT) was higher in rice plants than in Chinese cabbage. However, organically bound tritium(OBT) concentration is relatively higher in Chinese cabbage than in rice. The specific activity ratio(SAR) increased slowly after HTO exposure and decreased gradually with time. The behaviour of HTO in the soil was affected by the environmental conditions.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.115-115
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• 1995

저자 등은 일련의 식물엑스에 대하여 항위염 및 항궤양효능에 관한 검색을 실시하여 오리나무수피의 MeOH엑스가 현저한 효과가 있음을 예지 하였으므로 그에 대하여 보다 구체적인 실험을 실시하였다. 즉 MeOH엑스를 Hexane, CMCl$_3$, BuOH로 계통적으로 추출하여 상기의 분획 및 잔사인 물분획을 제조하여 이에 대한 실험을 실시하였다. 소화성궤양이 공격인자와 방어인자의 불균형에 의해 형성됨을 Shay가 주장함으로써 공격인자의 억제를 알아보기 위한 Mizui 등의 방법인 HClㆍEtOH 유발 위손상 실험과 Guth 등의 Aspirin 위손상 실험 방법에 따라서 위 손상정표를 관찰하였다. Shay의 방법에 따라서 위궤양 모텔은 유문을 결찰하고 검체를 십이지장내에 투여하고 처치를 완료하고 12시간 후에 궤양정도와 또한 4시간의 유문결찰에 의한 위액분 비량, pH 및 산분비량에 미치는 영향을 관찰하였다. 또 염산과 pepsin 등에 의한 점막 손상에 대한 방어인자의 증강요인인 위 mucous membrane의 mucus분비를 알아보기 위한 absoluteㆍ에탄올 위손상에 대한 예방효과 시험을 시행하였다. 이 실험의 결과, 오리나무 MeOH엑스의 항위염 및 항위궤양효과는 BuOH 분획에서 강력한 작용이 있었으며 이 분획은 aspirin 유발 위손상 및 shay 궤양에 효과를 나타내었고 또한 mucin량의 증가를 보여주었다. 그러나 이 분획은 위액, pH 및 산분비량에 영향을 나타내지 아니하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.30-34
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• 1988

In roastal fish farms the farmers, especialy engaging in dealing with the floating cage culture, going to know about relationships between holding capacity and water quality in cage. Some of water quality managers and specialists studing physiological ecology understand that the key of water quality management concerned fish farming is budget of dissolved oxygen. This paper deals with oxygen budget in floating cage of the yellow tail farms at southern coastal area in Korea. The sampling station is located at Konli-Do fish farm near Chungmu, and the data is collected for 24 hours from 3:00 p.m. 8th September 1987. In result, the needed oxygen coming after the consumption by the rearing fish had been supplied with the tide current exchange, the sum of oxygen produced by phytoplankton photosynthesis and diffused from atmosphere are no more that $43\%$ for the needs of sea water consumption included respiration of planktons and decomposition of organic matters. The optimum holding capacity of cage is possible to compute with the calculation of minimum diurnal water exchange rate $[Qin{\cdot}V^{-1}\;(C-\bar{c})]$ through net mesh of cage.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.347-355
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• 2020

Several sensors have been developed for soil and plants to assess plant stress due to climate change. Therefore, the objective of the study is to nondestructively evaluate temperature stress on plant by monitoring climatic and soil conditions and plant responses using various sensors. Plant responses were monitored by electrical conductivity in plant stem and sap flow rate. Electrical conductivity in plant stem reflects the physiological activity of plants including water and ion transport. Fully grown Brassica oleracea var. italica was exposed to 20/15 ℃ (day/night) with 16 h photoperiods as a control, low temperature 15/10 ℃, and high temperature 35/30 ℃ while climatic, soil, and plant conditions were monitored. Electrical conductivity in plant stem and sap flow rate increased during the day and decreased at night. Under low temperature stress, electrical conductivity in plant stem of Brassica oleracea var. italica was lower than control while under high temperature stress, it was higher than control indicating that water and ion transport was affected. However, chlorophyll a and b increased in leaves subjected to low temperature stress and there was no significant difference between high temperature stressed leaves and control. Free proline contents in the leaves did not increase under low temperature stress, but increased under high temperature stress. Proline synthesis in plant is a defense mechanism under environmental stress. Therefore, Brassica oleracea var. Italica appears to be more susceptible to high temperature stress than low temperature.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.362-366
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• 2012

To explore on the defense strategies against hervivory of five Viburnum species, morphological characteristics of the leaf, leaf domatia structure and the number, herbivores insects and mites on the leaves, collected from the trees growing in Wonju-si, Pyeungchang-gun, Taebaek-si, Taean-gun, Bonghwa-gun, Sancheung-gun and Jinju-si were investigated from May 2009 to October 2011. Domatia of V. carlesii reveals pocket type, these of V. burejaeticum, V. dilatatum and V. wrightii reveal tuft type, and that of V. odoratissimum var. awabuki reveals pouch type. Domatia number per leaf proves the highest figures, 24.0/leaf for V. burejaeticum, and the lowest, 4.9/leaf for V. carlesii. Leaf surface trichomes of four Viburnum species except for V. odoratissimum var. awabuki are mainly stellate and hispid on the leaf-blade and veins, and dense stellate trichomes on the upper leaf surface of V. carlesii, V. burejaeticum, and V. dilatatum are observed till late growing season. Extrafloral nectaries(EFN) on the terminal veins of five Viburnum species are observed. Pellucid dots on the lower leaf surface of V. dilatatum and V. wrightii might be a good defense strategies against herbivores. We observe many predatory mites eating nectar on large pellucid dots of V. dilatatum. Predatory mites number per leaf proved highly significant differences among tree species, and mean of mites number was highest values 8.1/leaf for V. burejaeticum, and the lowest 2.6/leaf for V. odoratissimum var. awabuki. These results indicate that temperate broadleave trees develop various defense strategies against herbivores for survival. The more studies on the defense strategies against herbivores of tree species might be needed for sustainable forest ecosystem.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.298-303
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• 2010

To explore on the defense strategies against hervivory of Juglans regia and J. mandshurica, morphological characteristics of the leaf, leaf domatia structure and the number, herbivores insects and mites on the leaves, collected from the trees growing in Mt. Chiak, Mt. Cheongtae, Mt. Jungwang, Namyangju-si and Wonju-si, were investigated from May to October, 2009. Domatia of J. mandshurica revealed tuft type, these of J. regia revealed pocket+tuft type. Domatia number per leaflet proved the higher figures, 28.3/leaflet for J. mandshurica, and the lower, 19.6/leaflet for J. regia. Leaf surface trichomes of J. regia revealed stellates only on the domatia structures, and that of J. mandshurica does dense stellates and glandular hairs on the leaf-blade and vein. Predatory mites' number per leaflet proved highly significant differences among tree species, and mean of predatory mites was higher values (4.8/leaflet) in J. mandshurica and lower values (3.5/leaflet) in J. regia. Small amount of nectar are found distal veinparts on the leaf margin of J. mandshurica. Dense glandular hairs on the lower leaf surfaces of J. mandshurica estimates useful strategy against herbivory. It may be possible to breed J. regia for better expression of leaf traits such as dense glandular hairs that increase predator populations and efficacy.

• Journal of Plant Biotechnology
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• v.31 no.4
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• pp.313-317
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• 2004

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases produced by a variety of cell type, and have a fundamental role in the degradation and remodeling of extracellular matrix. In this study, we screened the secretion of MMPs in leaves of different developmental stages and in response to environmental stress using tobacco. Compare with fully maturing leaves and older leaves, the rate of MMPs activity was high in expanding and younger leaves. It is tempting to speculate that MMPs may be involved in tissue modeling, which must occur during leaf expansion. The MMPs activity in tobacco leaves grown in the presence of stressors showed a significantly increase at salinity treatment and pathogen infection. The MMPs activity in salinity and pathogen treatment increased respectively, by 1.2- and 1.5-fold with respect to the control. These results suggest that MMPs may be involved in plant defence against adverse environment and pathogenic infection.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.357-362
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• 1994

Chitinases and $\beta$-1,3-glucanases are believed to be important in defending plane against pathogens. Here, we investigated the expression of chitinase(s) in Arabidopsis thaliana cell suspension culture system in response to ethephon (2-chloroethyl phosphonic acid) which produces ethylene or a microbial elicitor, a bacterial pectin-degrading enzyme, $\beta$-1, 4-endopolygalactronic acid Iyase (PGA Iyase), treatment. Chitinase activity was measured either by radio chemical assay using $^3$H-labeled regenerated chitin as substrate or western blot analysis using antibody raised against tobacro chitinase(S). With 1 mg/mL of ethephon or 100 m units/mL of elicitor treatment, maximum levels of activity were reached after 48h. We also investigated distribution of chitinase activity in seedlings, leaves, and root of A. thaliana and found that root have the highest chitinase activity.