The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of H2O2 against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.

본 연구의 목적은 외국인 혼승선박에서의 우리나라 선원과 외국인선원의 문화적 동질성과 승선근무 내성의 차이가 조직 커미트먼트에 미치는 영향을 실증적으로 검토하는데 있다. 해운산업에 있어서 외국인 선원 고용제한이 완화되어 외국인 선원이 혼승함에 따라 많은 문제점이 발생하고 있음에도 불구하고, 외국인 선윈 혼승선박에서의 문화적, 환경적 영향요인과 구성원의 태도와 행동에 관한 구체적인 연구가 이루어지지 않고 있는 실정이다. 따라서 본 논문은 외국인 선원 혼승선박에 승선하고 있는 우리나라 선원과 외국인 선원들을 대상으로 이문화 관리와 승선근무내성 및 조직커미트먼트의 관계를 실증적으로 검증하였다. 검증결과, 우리나리 선원과 외국인 선원간의 문화적 동질성과 승선근무내성에 차이가 있으며, 문화적 동질성과 승선근무 내성이 높은 집단의 조직커미트먼트가 일부 변수간의 관계를 제외하고 모두 높은 것으로 나타났다. 이러한 연구결과는 외국인 선원 배치 및 교육훈련 그리고 혼승선박 조직관리에 있어서 중요한 실무적 시사점을 제공할 것으로 사료된다.

"Juan1" is a new japonica rice variety of mid-late maturing, tolerance to lodging and adaptable to direct seeding which was developed by the rice breeding team of National Institute of Crop Science, RDA, in 2005. This variety is derived from a cross between Ilpumbyeo, a variety of good-eating quality and high yield, and SR18392-HB683-104. The Juanl has heading date of August 19 at ordinary planting in the middle plain. It has semi-erect plant type with culm length of about 80cm and tolerance to lodging. This variety shows susceptible to blast, bacterial blight, virus diseases and brown planthopper. The milled rice kernels of Juanl are translucent with non-glutinous endosperm, clear in chalkiness and medium short grain. It has also low amylose content of 18.8%, low gelatinization temperature and good palatability. The average milled rice yield of this variety was 5.68 MT/ha at ordinary planting in local adaptability test for three years from 2003 to 2005. Juan! would be highly adaptable to middle plain and mid-eastern coastal region of Korea.

"Seoanl" is a new japonica rice variety developed from a cross between Namyang9, a line of lodging tolerance and adaptable to reclaimed saline area, and Gyehwa7, a line of good-quality, adaptable to reclaimed saline area and high yield by the rice breeding team of National Institute of Crop Science, RDA, in 2005. This variety has about 131 days of growth duration from transplanting to harvesting in central plain area, and mid-western coastal area in Korea. It is about 73 cm in culm length and tolerance to lodging. It has also semi-erect pubescent leaf blade and slightly tough culm with good canopy architecture. The number of panicles per hill of Seoanl is slightly more than that of Hwaseongbyeo. Seoanl was susceptible to major diseases, blast, bacterial blight and viruses, and insect, brown plant hopper. This variety has lower amylose content of 18.8% and better palatability of cooked rice than those of Hwaseongbyeo. The milled rice yield performance of this variety is about 5.60MT/ha in local adaptability test for three years. Seoanl would be adaptable to central plain area and mid-western coastal area of Korea.

"Chugang" as a new double cropping potato variety for table use was bred in 2003 from a cross between H83005-2 with short dormancy and "Superior" with common scab resistance. It had been evaluated for short dormancy, growth adaptability and tuber characteristics every twice a year from 1990 to 1999. Regional yield trials had been performed from 2000 to 2002 at three locations, Jeju, Namhae and Gangneung of Korea, respectively. It has round oblong tuber shape with yellow skin and white flesh color. Its tuber dormant periods is approximately 50~60 days. It showed less physiological disorders such as cracking or knobs, and more tolerant to environmental stresses such as plant death by flooding and damages by frost or severe wind compared to "Dejima". Average yields of "Chugang" are 34.6 and 31.1 ton/ha at 90 days after planting in spring and autumn cropping, respectively. It is more resistant to common scab and less susceptible to late blight (phythophthora infestans) compared to "Dejima". However, it is susceptible to potato virus Y (PVY) and andean mosaic virus (AMV).

Plant peroxidases (PODs) have been shown to reduce hydrogen peroxide (H2O2) in the presence of an electron donor. Extracellular POD also induce H2O2 production, and can perform a significant function in responses to environmental stresses. We previously described the isolation of 10 POD cDNA clones from cell cultures of sweetpotato (Ipomoea batatas). Among them, the expression of the swpa4 gene was profoundly induced by a variety of stresses. In this study, transgenic tobacco (Nicotiana tabacum) plants overexpressing the swpa4 gene under the control of the CaMV 35S promoter were generated in order to assess the function of swpa4. Both transient expression analysis with the swpa4-GFP fusion protein and POD activity assays in the apoplastic washing fluid revealed that the swpa4 protein is secreted into the apoplastic space. The transgenic plants also evidenced a significantly enhanced tolerance to a variety of abiotic and biotic stresses. These plants harbored increased lignin and phenolic content, and H2O2 was also generated under normal conditions. Furthermore, they manifested increased expression levels of a variety of apoplastic acidic pathogenesis-related (PR) genes following enhanced H2O2 production. These results suggest that the expression of swpa4 in the apoplastic space functions as a positive defense signal in the H2O2-regulated stress response signaling pathway.

Abiotic stress conditions caused by temperature extremes, water availability, and ion toxicity severely limit plant growth and productivity. The degree of damage depends on the duration and intensity of the stress, developmental stage and plant species. Plants respond to stress through changes in gene expression, which are controlled by multiple signaling pathways. Our research has focused on gene expression analysis during low temperatures in cold-hardy Poncirus trifoliata, used as rootstock for enhancing cold tolerance in Citrus unshiu (Satsuma mandarin) scion in freeze-prone crop production areas. cDNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) and Quantitative Real-Time (RT) PCR were use to compare expression patterns in rootstock and C. unshiu grafted onto P. trifoliata. Genes with the following known functions were identified: signal transduction and regulation of gene expression (such as MAPK3), osmotic stress response, cell skeleton organization, vesicle trafficking and senescence. Differential expression of genes in roots of drought tolerant cucurbit species (Citrullus colocythis) is being studied in response to drought and plant hormones. A complex interplay between abscisic acid, jasmonic acid and salicylic acid signaling pathways regulates gene expression during adaptive responses to abiotic stress in Citrullus species. Functional analysis and detailed characterization of abiotic stress related genes is in progress.

Aluminum (Al) toxicity in plants is one of the major limitations to crop growth on acid soils. The Al-induced change of H+-ATPase expression has been regarded as an important mechanism for Al tolerance in soybean. To investigate whether translational regulation of plasma membrane H+-ATPase is involved in the response to Al stress, we conducted western - blot of this protein. The results show that western - blot of plasma membrane H+-ATPase in the "Sowon" (Al tolernace) significantly increased in translational expression level, while citric acid (50 μM) with Al (50 μM) treatment has not effected. In contrast, Al sensitive cultivar "Poongsannamool" inhibited expression level of plasma membrane H+-ATPase with Al treatment. Two - dimensional gel analysis were performed to determine the protein induction patterns of control and Al (50 μM, 24 h) treated soybean. There are many changes of plasma membrane proteins in both cultivars under Al stress. Especially "Sowon" was significantly enhanced the expression of the plasma membrane H+-ATPase in Al treatment. But protein expression of "Poongsannamool" was less than "Sowon". These results suggest that the regulatory role of plasma membrane H+-ATPase may involved the tolerance mechanism in soybean roots. At the present, transcriptional level of H+-ATPase is under investigation.

“Shinmichal1”, a waxy red winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross “Alchan”/“Chal2”during 1997. “Alchan” is a soft red winter wheat with high yield and good noodle quality. “Chal2” is a waxy wheat line crossed by “Kanto107” (Wx-A1b and Wx-B1b) and “BaiHuo” (Wx-D1b). “Shinmichal1” was evaluated as “Suwon306” in Advanced Yield Trial Test in 2002. It was tested in the regional yield trial test between 2003 and 2006. “Shinmichal1” is an awned, semi dwarf and soft red winter wheat, similar to “Uri” (check cultivar). The Heading and maturing date of “Shinmichal1” were similar to “Uri”. Culm and spike length of “Shinmichal1“ were 79 cm and 7.8 cm. “Shinmichal1“ had greater test weight (802 g) and lower 1,000-grain weight (31.8 g) than “Uri” (782 g and 35.2 g, respectively). It has resistance to winter hardiness, wet-soil tolerance, lodging tolerance and moderate post-harvest sprouting damage. “Shinmichal1” had higher flour yield (66.2%), ash (0.73%), protein (10.9%) and SDS sedimentation volume (40.7 ml) than “Uri” (64.7%, 0.53%, 9.3%, and 32.5 ml, respectively) and similar flour color to “Uri”. “Shinmichal1” had higher dough extensibility and lower dough strength than “Uri”. It is 5.2% of amylose content and had typical waxy starch pasting properties. Average yield of “Shnmichal1” in the regional adaptation yield trial was 5.24 MT ha-1 in upland and 5.58 MT ha-1 in paddy field, which was 3% and 8% lower than those of “Uri” (5.39 MT ha-1 and 6.09 MT ha-1, respectively). “Shinmichal1” would be suitable for the area above the daily minimum temperature of -10℃ in January in Korean peninsula.

A new black seed coat soybean variety, “Socheong” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Socheong was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Peking which was tolerant to lodging and with small seed size. The preliminary, advanced and regional yield trials for evaluation and selection of this variety were carried out from 2002 to 2006. It has determinate growth habit, white flower, brown pubescence, brown pod color, black seed coat, green cotyledon, elongated flattened seed shape, oval leaf shape and small seed size (15.7 grams per 100 seeds), and it was 3 days later in maturity than the check cultivar Cheongjakong. Socheong was higher, in the seed quality of sucrose and total sugar contents (6.8 and 8.2%) and isoflavone contents (1,754 ㎍/g) than the check cultivar. Futhermore, it has good characteristics for mechanical harvest, such as lodging tolerance, pod shattering and stem diameter. It also has been identified to have resistance to soybean mosaic virus symptom which was the troublesome soybean diseases. The average yield of Socheong was 2.21 ton per hectare in the regional yield trials carried out in four locations of Korea among seven locations from 2004 to 2006, which was 5 percent lower than the check cultivar Cheongjakong.

A new black seed coat soybean cultivar, “Heugmi” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Heugmi was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Milyang 68, which was middle maturing, resistant to lodging and SMV and with middle seed size and yellow cotyledon. The preliminary, advanced and regional yield trials for evaluation and selection of this cultivar were carried out from 2001 to 2006. It has determinate growth habit, purple flower, brown pubescence, black pod color, black seed coat, green cotyledon, spherical seed shape, oval leaf shape and middle seed size (24.8 grams per 100 seeds), and it was 2 days earlier in maturity than the check cultivar Cheongjakong. Heugmi was better in the seed quality of crude protein contents, sucrose and total sugar contents than the check cultivar. It also has been identified to have resistance to SMV which was the troublesome soybean diseases. The average yield of Heugmi was 2.53 ton per hectare in the regional yield trials carried out in seven locations of Korea from 2004 to 2006, which was 8 percent higher than the check cultivar Cheongjakong.

In order to examine the cross-tolerance of two chilling-tolerant cultivars (Donganbyeo and Heukhyangbyeo) and two chilling-susceptible cultivars (Hyangmibyeo and Taekbaekbyeo) to salt, paraquat, and drought, changes of physiological response and antioxidant enzymes were investigated. The seedlings were grown in a growth chamber until the 4-leaf stage. The seedlings were exposed to chilling at 5~circC for 3 days. For drought treatment, the seedlings were subjected to drought by withholding water from plants for 5 days. For paraquat study, plants were sprayed with 300~muM paraquat. For the salt stress, the seedlings were transferred to the Hoagland's nutrient solution containing 0.6% (w/v) NaCl for 4 days. Chilling-tolerant cultivars showed cross-tolerant to other stresses, salt, paraquat, and drought in physiological parameters, such as leaf injury, chlorophyll a fluorescence, and lipid peroxidation. The baseline levels of antioxidative enzyme activities, catalase (CAT) and peroxidase (POX) activities in chilling-tolerant cultivars were higher than in the chilling-susceptible cultivars. However, there were no differences in ascorbate peroxidase (APX) and glutathione reductase (GR) activities between chilling-tolerant and -susceptible cultivars in untreated control. CAT activity in chilling-tolerant cultivars was higher than that in chilling-susceptible cultivars during chilling, salt, and drought treatments, but not during paraquat treatment. However, other antioxidative enzymes, APX, POX, and GR activities showed no significant differences between chilling-tolerant and -susceptible cultivars during chilling, salt, paraquat, and drought treatments. Thus, it was assumed that CAT contribute to cross-tolerance mechanism of chilling, salt, and drought in rice plants.