Gamma irradiation has been used as a tool for plant mutation breeding to select new cultivar with improved characteristics. Generally, the irradiation of seeds with high doses of gamma rays disturbs the synthesis of protein, hormone balance, and enzyme activity. And also, high dose of gamma rays to reduce plant height, number of tiller, and root length, although the effect of gamma-irradiated plants may depend on the species and cultivar or stress conditions. Biological effects of radiations can be divided into two types according to dose range and periods of exposure. Acute irradiation represents exposure to high-dose of irradiation over short period time, whereas the chronic irradiation is comprised of exposure to low doses of radiation over extended period of time. To compare the effects of acute and chronic exposure to ionizing radiation on two wheat cultivars (K4191 and Geumgangmil), we measured their germination rate, seedling height, and root length. In order to understand the influence of antioxidant-related genes and DNA repair-related genes, we used qRT-PCR methods to identify their expression levels. To study the behavior of a radiation-induced free radical, gamma-irradiated seeds were used for ESR spectroscopy. Plant growth pattern was showed positive correlation with ESR results. This study indicates that low level chronic radiation exposure is even more serious effects than short doses of high level radiation according to different wheat cultivar.

Perilla frutescens (L.) is an edible plant, not only used as s food ingredient, but also in skin cream, soaps, and medicinal preparetions. ‘Atom-Ros’, a perilla (Perilla frutescenc (L.) Britt. cv. Chookyoupjaso was developed in 1995 by 200 Gy gamma irradiation-mutagenesis. This new cultivar has high rosmarinic acid content more than two fold compare with ‘Chookyoupjaso’ control. The observed phenotypical difference was changed leaf color of the ‘Atom-Ketone’ from violet to green. The yield potential of this cultivar (123.5 kg/10a) was 2.14 fold higher than that of ‘Chookyoupjaso’ (57.65 kg/10a). The methanol extracts of ‘Atom-Ros’ were tested for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophase cells. Atom-Ros showed significant inhibition of NO production. This rosmarinic acid extracted from ‘Atom-Ros’ has a good potential to be developed as an antioxidant agent.

Perilla frutescens (L.) is an annual herbaceous and ornamental plant in the Lamiaceae family. Perilla frutescens (L.) Britt.cv.Chookyoupjaso were irradiated using a 200 Gy gamma ray in 1995. By HPLC analysis, this new cultivar significantly induced isoegomaketone content compared with ‘Chookyoupjaso’ control. The phenotypical difference was the changed leaf color of the ‘Atom-Ketone’ from violet to green. The yield potential of this cultivar (106 kg/10a) was 1.83 folds higher than that of ‘Chookyoupjaso’ (57.65 kg/10a). The methanol extracts of ‘Atom-Ketone’ inhibit nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. This extract was further partitioned using ethyl acetate (EtOAc), butanol (BuOH), and water. The EtOAc fraction (EF-Atom-Ketone) was evaluated for antiinflammatory activities. These results indicated that the EF-Atom-Ketone reduced NO production by inhibiting inducible nitric oxide synthase (iNOS) expression. The EF-Atom-Ketone treatment also significantly diminished expression of MCP-1 and IL-6. Therefore, ‘Atom-Ketone’ reveals the potential therapeutic use of bioactive

본 연구에서는 감태 효소 추출물과 그것의 폴리페놀 추출물의 화장품 원료로서의 효능을 알아보기 위하여 항산화, 항당화, 미백, 항염 효과와 관련된 실험을 실시하였다. 감태 효소 추출물과 폴리페놀 추출물은 강력한 라디컬 소거능을 가지고 있으며 BSA/Glucose 시스템에서 최종당화생성물의 형성을 저해하는 항당화 활성과 타이로시네이즈 저해를 통한 우수한 미백력을 가지고 있음을 확인하였다. 또한 두 추출물 모두 세포 내에서 PGE2와 NO 생성 저해를 통한 항염 효과를 나타내었다. 이러한 결과를 종합해 볼 때, 감태 효소 추출물과 그 폴리페놀추출물은 화장품 원료로서의 응용 가능성이 있을 것으로 사료된다.

In order to adapt to various environmental stresses, plants have employed diverse regulatory mechanisms of gene expression. Epigenetic changes, such as DNA methylation and histone modifications play an important role in gene expression regulation under stress condition. It has been known that some of epigenetic modifications are stably inherited after mitotic and meiotic cell divisions, which is known as stress memory. To understand molecular mechanisms underlying stress memory mediated by epigenetic modifications, we developed Arabidopsis suspension-cultured cell lines adapted to high salt by stepwise increases in the NaCl concentration up to 120 mM. Adapted cell line to 120 mM NaCl, named A120, exhibited enhanced salt tolerance compared to unadapted control cells (A0). Moreover, the salt tolerance of A120 cell line was stably maintained even in the absence of added NaCl, indicating that the salt tolerance of A120 cell line was memorized even after the stress is relieved. By using salt adapted and stress memorized cell lines, we intend to analyze the changes of DNA methylation, histone modification, transcriptome, and proteome to understand molecular mechanisms underlying stress adaptation as well as stress memory in plants.

A complete diallel cross was performed to determine the inheritance of allelopathic potential and combining ability of six rice germplasm that showed different level of allelopathic potential against barnyardgrass. Parents and F1 of 30 crosses were assessed for allelophatic potential in field condition. Barnyardgrass (Echinochloa crus-galli (L.) Beauv. var. frumentaceae) was used for rice allelopathic potential indicator which was observed in height and shoot dry weight, then suppression percentage were calculated by comparing to barnyardgrass grown in control plot (no rice). It was found that general combining ability showed no significant effect, whereas specific combining ability and reciprocal effect were significant. Variance analysis confirmed that genetic control of allelopathic potential in rice against barnyardgrass was mostly directed by dominance gene effect. The dominant genes were associated with high allelopathic potential and recessive genes were associated with low allelopathic potential. Heritability in broad sense for barnyardgrass dry weight suppression was around 41%; whereas for barnyardgrass height suppression was 51%. However, heritability in narrow sense was very low. The finding suggests that accumulation of genes associated with allelopathic potential would be a strategy to develop promising varieties in reference with the specific combining ability of cross combinations.

A new kidney bean cultivar, “Noghyeob 1” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2005. “Noghyeob 1” was selected from a cross between KLG50074 and KLG50063. It has determinate growth habit, white flower, green pod color, oval shape of crossed section of pod at the harvesting time for edible pod, white seed coat and middle seed size (21.1 grams per 100 seeds). The average yield of edible pod of “Noghyeob 1” was 24.25 M/T per hectare in the yield trials which were carried out at the green house in spring and autumn in 2005. It was 7 percent higher than that of the check cultivar “Kangnangkong 1”.