• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.309-314
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• 2009

Incidence of rice stripe disease, caused by Rice stripe tenuivirus (RSV), was surveyed during 2002 to 2004. The incidence area and ratio of diseased fields were decreased gradually during those period. Rate of diseased plants were 45.8%, 45.0% and 43.7% in the susceptible cultivars Chucheong, Saechucheong and Ilpum, respectively. However, the rate was 4.4% in resistant cultivar Hwaseong. In addition, breakdown rate was also significantly high in the susceptible cultivars in Chucheong, Saechucheong and Ilpum showing 33.6, 33.2 and 31.9%, respectively. In Hwaseong, the breakdown rate was 0.8%. Collection efficiency was compared between two insect vector collection methods. Insect-sucking machine method was much more efficient than sweeping net method in collecting small brown plant hopper (SBPH). According to the survey of the population density of the insect vector during 2002 to 2004, the national average population density was gradually decreased year by year, 3.6, 2.3, and 1.3%, respectively. This result was significantly related with the decrease of the incidence of rice stripe disease. Control efficiency of rice stripe disease by treating several seedling box and water surface with insecticides against SBPH resulted that imidacloprid GR, Fipronil FG, Clothianidin+Probenazole GR and Thiamethoxam GR showed over 80% of control efficiency at 28 days after treatment at the early stage in nursery.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.642-649
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• 2011

Ginseng growth is largely affected by characteristics of soil in Ginseng field. In this study, we determined the critical ranges of physico-chemical properties of soil for optimization of ginseng growth by analyzing the soils from Anseong and Pocheon regions in Gyeonggi province. Fresh weight of ginseng was 2 to 5 fold higher in good growth field compared to poor growth field within Anseong region. In the case of Pocheon region, 1.5 to 2 fold differences of fresh weight of ginseng was observed between good and poor growth field. These results indicate the difference of ginseng growth even in the same region. Based on these results, critical ranges of physico-chemical properties of soils were determined by comparing the good and poor growth field of each regions, which are follows; more than 50% of soil porosity, 2.0~2.8 g/kg of total nitrogen, 500~900 mg/kg for Av. $P_2O_5$, 2.3~3.5 $cmol_c\;kg^{-1}$ for Exch. Ca in Anseong; less than 13% of liquid phase, 400~650 mg/kg for Av. $P_2O_5$, 4.0~4.7 $cmol_c\;kg^{-1}$ for Exch. Ca, less than 0.8 and 0.5 $cmol_c\;kg^{-1}$ for Exch. Mg and K, respectively, in Pocheon. Interestingly, we found that ginseng growth was affected by exchangeable base ratio (Ca:Mg:K) especially in Anseong region, which were 6:2:1 in good growth field while 4:2:1 in poor growth field. Critical ranges for nutrient contents of ginseng leaves were also characterized, which are less than 0.2% and 0.22% of each P and Mg, respectively, in Anseong, while less than 1.8% and 0.18% of each N and P, respecively, and 1.5~3.0% of K in Pocheon. In addition, we determined critical ranges for inorganic nutrient contents in the current study.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.589-596
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• 2013

Vaccinium bracteatum Thunb. is an evergreen plant that belongs to the Genus Vaccinium distributed in Korea, and its fruit has been used for food by the common people and thus has a high possibility of commercialization. Therefore, the habitat environment and individual characteristics of V. bracteatum in Jeju Island were investigated to obtain the basic data for commercialization and preservation. The results showed that V. bracteatum is mostly distributed on the southern slope of Mt. Halla at an altitude of 100 to 500 m. V. bracteatum that occurred in the quadrat were total 30 individuals, which had an average height of 6.0 m, an average DBH of 7.8 cm, and an average number of trunk of 4.3. As for the community structure of the habitat, the average percentage of vegetation cover for the tree layer was 36%, while that for the subtree layer was 78%, which emphasized the importance of the subtree layer. The total number of species that occurred in the quadrat was 76. For the tree layer, total 10 species occurred, which include 2 species of evergreen coniferous trees, 3 species of evergreen broad-leaved trees, and 5 species of deciduous broad-leaved trees. For the subtree layer, total 24 species occurred, which include 1 species of evergreen coniferous tree, 11 species of evergreen broad-leaved trees, and 10 species of deciduous broad-leaved trees. Among these, Eurya japonica Thunb. was the species with a high relative contribution, which threatened V. bracteatum For the shrub layer, 27 species occurred including Cinnamomum japonicum Siebold, and for the herbaceous layer, 64 species occurred including Ardisia crenata Sims. The similarity between the habitats of V. bracteatum was very low, and it did not prefer a characteristic community. The V. bracteatum community around Shinrei stream was distributed on the surrounding area adjacent to the slope of the stream rather than the slope. There were a lot of basins, but the branches, which did not receive sunlight, had withered. It is thought that V. bracteatum would decline if the forest formation continues.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.187-194
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• 2010

The soybean stay green mutant genotype (SSG) derived from the nuclear gene, d1d2, and cytoplasmic gene, cytG, inhibit the breakdown of chloroplast in the leaves, pod walls, seed coats, and embryos during maturity. Soybean seed with black seed coat and green cotyledon (SBG) are preferred than black seed coat with yellow cotyledon (SBY) especially for cooking with rice and as source of traditional food in Korea. The researchers evaluated the seed's chlorophyll content of SSG and introduced SSG to the SBG variety breeding program. The seed chlorophyll content of SSG with d1d2 was $39.93{\sim}60.80\;{\mu}g/g$ and SSG with cytG $38.08{\sim}39.89\;{\mu}g/g$. The Korean SBG variety which was derived from SSG with cytG, contains $16.35{\sim}37.73\;{\mu}g/g$. The composition of seed chlorophyll differs according to the genetic background of SSG genotype. Inheritance study showed that cotyledon color was segregated 15:1 (yellow:green) at $F_2$ seed indicating two recessive genes control green cotyledon as revealed by previous study. Only less than 3% soybean lines showed black seed coat with green cotyledon among crosses SBY and SSG (d1d2). Results showed that SSG with d1d2 can be used as a good source for SBG with high chlorophyll content in the seed cotyledon, but due to the complex genetic behavior, breeding resource of SBG with d1d2 should be prepared to improve the breeding efficiency for development SBG variety.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.638-646
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• 2015

To increase the utility of seeds in plant resources, seeds of 6 Aster species(A. incisus, A. hayatae, A. koraiensis, A. scaber, A. spathulifolius, and A. yomena) were subjected to experiments to develop adequate methods for sprout production. To study optimum germination conditions, germination rates of the seeds were analyzed at different temperature (15, 20, 25, and $30^{\circ}C$) and light conditions. A longitudinal growth experiment was performed in dark conditions for 10 days. Seedlings, with optimum germination rate and longitudinal growth, were placed in the light for 0-3 days to seek the adequate greening periods. Sprouts grown under optimum environmental conditions were placed in vessels with or without ventilation, and stored under $4^{\circ}C$ and $10^{\circ}C$ to examine storage environment and period. As a result of this analysis, seeds were selected that germinated over 50% within 12 days. Longitudinal growth was promoted at $20-25^{\circ}C$, and optimum growth was obtained with 7-9 days. As greening days increased longitudinal growth was retarded, but orbital growth of radicles and cotyledons was promoted. Considering all these factors, greening treatment of 2 days showed the best results. In a storage ability experiment, the best result was achieved by storage in vessels without ventilation under $4^{\circ}C$. Ventilation prevented rotting of sprouts, but reduced moisture contents of sprouts. Most sprouts were fresh at $4^{\circ}C$ for 3-6 days. In particular, sprouts of A. hayatae and A. yomena had high keeping quality, and remained fresh over 3 days even at $10^{\circ}C$.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.385-394
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• 2008

Larvae of Monochamus saltuarius showed normal growth and development on conifers of Pinus koraiensis, P. densiflora, Abies holophylla, Larix leptolepsis, P. bungeana, and P. rigida, respectively, but the conifers influenced significantly the body weight and the survival rate of larvae. Though the larval body weights were in a wide spectrum among treatments, growth curves of them were very similar from each other, showing continuous increase from the early larval stage to about 3 months old. The body weight was decreased slightly after the feeding period of the early 3 months. The size of larvae and adults became the largest from P. bungeana fed larvae. The mid-sized ones were from P. koraiensis, P. densiflora and A. holophylla. Small ones came from L. leptolepsis and P. rigida. The larval growth was retarded without water supply. Overall survival rates from the early stage of a larva to a fertile adult were 53.6% from P. koraiensis; 51.8%, P. densiflora; 34.7%, A. holophylla; 17.8%, P. bungeana; 16.7%, L. leptolepsis; and 12.3%, P. rigida. Adults from larvae fed the 6 species of conifers, respectively, were grown into the reproductively potent adults, which laid viable eggs. A few of overwintered larvae did not pupate and remained still as a larva until the late October of the year. Data from the field survey, the head width emerged from P. koraiensis was larger than that of L. leptolepsis. The adult emergence hole in P. koraiensis was larger also. While, the size of the emergence hole was larger in the artificially innoculated log of P. koraiensis, which was kept for a larva to be with a minimized food competition and sufficient water supply, than that of the field.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.406-414
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• 2010

Antioxidative activity, including inhibitory activities of angiotensin I converting enzyme(ACE), aminopeptidase N(APN) and $\alpha$-amylase, was investigated in the methanol extracts from Theaceae plants native to Jeju island, in order to select the plant species containing bioactive materials for functional food or medicines. ACE inhibitory activity was above 50% in Ternstroemia japonica(stem bark) and Cleyera japonica(leaf), and APN inhibitory activity was low to be positive only in C. japonica(leaf, stem bark) and T. japonica(stem bark). $\alpha$-Amylase inhibitory activity was above 30% in Camellia japonica(fruit), Eurya emarginata(stem), T. japonica(stem bark) and Thea sinensis(stem). The antioxidative activity, estimated by the DPPH radical scavenging capacity, was above 30% in C. japonica(stem bark), T. japonica(stem bark) and T. sinensis(leaf). Particularly, the antioxidative activity analyzed by dot-blot test was very high in C. japonica(stem bark) relatively to those of other plants, and remained high in the low concentration($1.25\;{\mu}g/m{\ell}$). From the TLC analysis of antioxidative compounds, EGC(Rf 0.26) was found to have high activity in stem bark of C. japonica and EGCG(Rf 0.09) was found to have high activity in stem bark of C. japonica, E. emarginata, and T. japonica. Five bands (Rf 0.54, 0.46,0.44, 0.16, 0.03) which were not identified as compared with catechins were detected as polyphenolic compounds on the TLC plates sprayed with the Folin-Ciocalteu solution or the Ferric chloride-alcohol solution. These results suggests that Theaceae plants except E. japonica could be potentially used as a resource of bioactive materials for functional foods or medicines and further research is reguired to identify the bioactive substances and determine the functions of them.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.72-78
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• 2020

In this study, miscanthus with C/N ratio of 224 were applied to the soil and treated with 0 (control), 10 tons and 20 tons·ha^-1 to improve the soil and promote crop growth. As a result, soil organic matter content increased from 11.0 g·kg^-1 before the test to 16.3 after 3 years. Soil cation exchangeable capacity increased to 15.3 cmol_c·kg^-1 after 3 years. In the sweet sorghum, stem was the most thickest at 20 tons·ha^-1 application of miscanthus and the highest juice amount per plant was 60 ml. The yield index multiplied by the soluble solids content of juice and juice amount was the highest at 1,913 for 10 tons application and 1,851, 1,839 for 20 tons, control respectively. Number of sweetpotato storage root were 2,9 in 20-tons application plot, the same as control, and 10-tons application plot was 3.6, the most. Two-year average yields of 20 tons plot and control were low at 2,579 kg/10a and 2,708 respectively, and 10 tons plot was the highest at 3,289. For onions, the biomass application did not effect the yield. but onion plant and leaf length were longer in 20 tons plot than in control or 10 tons. The yield of garlic was 2,630~2,901 kg/10a and there was no effect of miscanthus application. Plot of 10 tons application were the longest in plant and leaf length, and the number of scale was 8.2-8.3 per in bulb, and 8.9 tons·ha^-1 in control. Therefore, it was confirmed the possibility that miscanthus biomass application of about 10 tons·ha^-1 could improve the soil condition and promote crops growth and yield.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.284-288
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• 2005

This study was conducted to clarify the effects of supplying methods of selenium on the growth and Se uptake of hydroponically grown tomato plants. Tomato seeds (Lycopersicum esculentum Mill. cv. Momotaro T-93, Daki Seed Co.) were sown in plug tray with fifty holes, and raised for sixty days. Tomato seedlings transplanted to coco fiber slabs were supplied with the nutrient solutions adjusted to EC $2.3dS{\cdot}m^{-1}$ and pH $5.8\~6.2$ recommended by the Japanese Horticultural Experiment Station. Selenium forms used were inorganic $SeO_2$ (here in after referred to Se) and organic selenium chlenium with sugar fatty acid ester (here in after referred to chelated-Se). 10 ppm selenium solutions were treated to tomato plants with foliar applications, drenching, and foliar application plus drenching. Growth characteristics in terms of plant height, number of leaves, leaf area and chlorophyll content were significantly increased in the plot of foliar application ot Se, and in the plot of foliar application plus drenching of chelated-Se than other plots, respectively. Transported contents of selenium into the tomato fruits were highest as 0.302 ppm in the plot of foliar application plus drenching of chelated-Se. Also, it had tended to be higher in the plot of foliar application plus drenching than in the plots of foliar application or drenching in both of Se and chelated-Se. Foliar application and drenching of organic chelated-Se were effective to produce the functional tomato fruits.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.600-607
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• 2015

In vitro and in vivo experiments using Achyranthis radix and Drynariae rhizoma extracts were conducted. Antioxidant properties were analyzed and the effects on bone, glucose and lipid metabolism were investigated. Drynariae rhizoma (64.67%) obtained higher DPPH radical scavenging activity compared to Achyranthis radix (19.03%). Similar results were obtained in the reducing power. No differences were observed on the ABTS radical scavenging ability and SOD. In contrast, Achyranthis radix (77.60%) has higher chelating ability compared to Drynariae rhizoma (46.21%). In vivo experiments revealed higher plasma TBARS in OVX-DR than in OVX-AR. Opposite result was seen in erythrocyte TBARS. Hepatic, nephritic and erythrocyte enzymes were considered for the antioxidant enzyme activities. GSH-Px and PON of hepatic enzymes were higher in OVX-AR. While the CAT and GR were higher in OVX-DR. SOD, GSH-Px, GR and PON of nephritic enzymes of OVX-DR were higher compared to OVX-AR. Almost similar values were obtained in CAT using both extracts. The OVX treated rats obtained higher CAT and GR in the erythrocyte enzymes compared to SHAM. The SOD of erythrocyte enzymes in OVX-DR was higher compared to OVX-AR. On the other hand, the GSH-Px was higher in OVX-AR.