• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.773-786
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• 2016

Grape cultivar "Campbell Early" account for 70% of table grape in Korea and Leaf Spot Disease caused by Pseudocercospora vitis is one of a major disease in greenhouse and field grown area during late summer season in both of organic and conventional grape farm. Leaf spot disease can cause lowing of sugar content in fruit and vine growth and very difficult to control especially in organic field. Photosynthesis ability and chemical components are compared between leaf spot disease infected leaves with degree of necrotic area. With increase of disease necrotic area, $CO_2$ differential value, water use efficiency and $CO_2$ assimilation and respiration ratio are decreased proportionally and on the other hand, stomatal conductance value is not affected by disease necrotic area. Chlorophyll contents are also decreased by 50% in heavily infected leaves and imply decrease of chlorophyll contents is a major source of photosynthesis ability decline. With increase of disease necrotic area in leaves, total nitrogen and phosphate contents are decreased and on the other side, total carbon, potassium, calcium and magnesium contents are increased. From this research, we can infer that not only chemical control program is important in control of leaf spot disease but also fertilizing program is significant especially in organic agronomical control of fungal disease in grape cultivar "Campbell Early".

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.64-68
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• 2019

To utilize soybean leaf, which is a waste product in soybean production, as a value-added food material, this study aimed to investgate the extraction efficiency of isoflavone from soybean leaf and to characterize physicochemical properties of the extract. Maximum isoflavone content of $59.74{\pm}4.54mg/l$ was obtained from soybean leaf extracted at $90^{\circ}C$ for 12 h. DPPH (1,1-diphenyl-2-pricylhydrazyl) radical-scavenging activity and total polyphenol contents reached maximum levels of $67.26{\pm}3.64%$ and $1,688.68{\pm}97.37{\mu}g/ml$ chlorogenic acid equivalent, respectively. Based on the contents of isoflavone and total polyphenol, and DPPH radical-scavenging activity, optimum extraction conditions for soybean leaf using water as solvent were $90^{\circ}C$ and 12 h.

• Korean journal of food and cookery science
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• v.31 no.4
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• pp.423-430
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• 2015

This study was carried out to investigate the effects of dandelion leaf, root and whole part extracts on the physicochemical characteristics of pork patties stored at $4^{\circ}C$ for 10 days. Four types of pork patties were evaluated: ice-water-added (T0), dandelion leaf extract (T1), dandelion root extract (T2) and dandelion whole part extract (T3). The pH decreased significantly during storage, but increased after 10 days of storage. The pH was highest in T0 during storage. The L value of T0 increased whereas T1, T2 and T3 did not significantly changed during storage. The a value decreased with a longer storage period, and the a values for T1, T2 and T3 were higher than that of T0 during storage. The b value did not change significantly during storage. The TBARS increased with a longer storage period, and the values for T0, T1, T2 and T3 were 0.87, 0.29, 0.47 and 0.31 mg MA/kg, respectively, after 10 days of storage. The VBN content value of T0 increased, but those of T1, T2 and T3 did not significantly change during storage. The water holding capacity of T0 decreased, but those of T1, T2 and T3 did not significantly change during storage. Cooking loss increased during storage and that of T0 was higher than those of T1, T2 and T3. Hardness and chewiness decreased while springiness and cohesiveness increased during storage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.201-201
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• 2017

Delayed stem senescence of soybean is a phenomenon of retarded leaf and stem yellowing, where plants maintain a high stem water content and remain chlorophyll in leaf and stem at maturity stage. This phenomenon was one of the most important physiological disease in Japanese soybean cultivation. The occurrence of delayed stem senescence was affected by sowing time. And the most of Japanese field, soybean seeds were sowed in June. June is the rainy season in Japan, and the soil water content of field become higher in this season. In this study, the effects of late sowing (July sowing) on the yield and the occurrence of delayed stem senescence in soybean cultivars Enrei, Tachinagaha and Ayakogane were examined from 2013 to 2015, in the experimental farm at Nihon University (Fujisawa-city, Kanagawa, Japan). The seeds of all cultivars were sowed in June (June-normal density plot) or July (July-normal density plot, July-high density plot and July-super high density plot) in field experiment. The pot experiments were carried out in 2014. In all cultivars, the yield of July-high density plot and July-super high density were higher than that of June normal density plot. And the yield of June-normal density plot was the same as that of July-normal density plot. In all cultivars, the occurrence of delayed stem senescence was increased by seeding in June sowing. And in July sowing plots, no significance difference in the occurrence of delayed stem senescence was observed among density plots. One of reason about the increasing the occurrence of delayed stem senescence in June-normal plot was the increasing of the damaged seeds by bean bugs. Add one of reason about the decreasing of the occurrence of delayed stem senescence of July plots was the decreasing of the amount of cytokinin supplied from root to top and water stress after the flowering time was improved compared with the June plot. In conclusion, the yield of Enrei, Tachinagaha and Ayakogane were not changed by changing the sowing time from June to July. In all cultivars, the occurrence of delayed stem senescence were decreasing by seeding in July.

• Journal of Environmental Science International
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• v.22 no.1
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• pp.17-23
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• 2013

In order to evaluate the effect of various organic soil conditioner ratios on the soil moisture content and growth of Cotoneaster horizontalis, a container type for wall-planting experiment was conducted in a greenhouse at Konkuk University under non-irrigation. The experimental planting grounds were prepared with different organic soil conditioner ratios ($A_1L_0$, $A_8L_1$, $A_4L_1$ $A_2L_1$ and $A_1L_1$), and a drought-tolerant ornamental variety of Cotoneaster horizontalis was planted. The change in soil moisture content, plant height, number of branches, number of dead leaves, number of leaves, number of shoots, length of node, length of leaf, width of leaf, root-collar caliper, chlorophyll content, and survival rate were investigated, from April to Jun 2010. The results of soil moisture content measurements were analyzed with weight units in the container type for wall-planting during the dry summer season. The soil moisture contents were significantly enhanced in the container type for wall-planting in increasing order as the amount of soil conditioner level was increased ($A_1L_1$ > $A_2L_1$ > $A_4L_1$ > $A_8L_1$ > $A_1L_0$). Compared to the control treatment application (amended soil with 100% + organic soil conditioner 0%), the highest plant growth was observed in the treatment of $A_1L_1$ application (amended soil with 50% + organic soil conditioner 50%). However, the differences between the organic soil conditioner ratio treatments of $A_1L_1$, $A_4L_1$, and $A_8L_1$ organic soil conditioner application were mostly not significant. The survival rate increased with the increasing application of organic soil conditioner, but in the control treatment application all the plants died. The experimental results from clearly demonstrated that the organic soil conditioner improved the survival rate more than the growth of Cotoneaster horizontalis. Therefore, Cotoneaster horizontalis is expected to be a highly valuable shrub for green wall systems, when considered for us in integration system or for increasing soil water contents in planting grounds.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.24-29
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• 1984

Seedling yield of panax ginseng depended on soil water in a modified Yang-jig seedbed with rice hull mulch and peat application which increased soil water content. Water dependency tended to increase with the increase of potassium in soil. Effect of potassium on water dependency seemed to be constant in certain range of soil water which might be the optimum water for seedling growth. Partial correlation coefficient between seedling yield and water was significant in relation to organic matter (OM), Mg and Ca. The best multiple regression of seedling yield was with $H_2O$, K and Ca. Available phosphorus (P) in soil increased with low level of peat but decreased with high level or with mulching. There was interaction between mulching and peat for P. There was significant linear relation between two of pH, $H_2O$, Ca, Mg, K, OM except between K and $H_2O$ or pH. Ammonium nitrogen negatively correlated with Mg Quadratic relation held between $NO_3-N$ and K or $NH_4-N$ and between P and K+Ca+Mg. Quadratic relation was more significant than linearity between soil factors. Mulching increased stem length. Leaf area index ranged from 1.06 to 1.67. Leaf area per plant ranged $16.0-18.8cm^2$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.60-65
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• 1982

In order to observe the degree and response of drought-resistance and its physiological mechanism in barley and wheat seedling stage, 5 species (16 cultivars) were tested for the changes of nitrate reductase and protease activity and the accumulation of free proline, by being subjected to water stress by withholding watering for 8 days at 10 days (at the 3rd leaf stage) after emergence and by imposing water stress to the excised first leaf by polyethyleneglycol solution (osmotic potential, -20 bars) for 48 hours. The average rate of decrease of all cultivars was 42% in nitrate reductase activity and 73% in protease activity. But proline content in water stress was increased 10 folds more than that of control. The decrease4 rate of nitrate reductase activity in 5 species was in the order of wheat < rye < covered barley < naked barley < two-row barley: wheat being the lowest. The decreased rate of protease activity in 5 species was in the order of wheat > rye > two-row barley > covered barley > naked barley: wheat being the" heighest. The accumulated amount of free proline in 5 species by water stress was in the order of wheat > covered barley > rye > naked barley > two-row barley. And the increased ratio (folds) of free proline of water stress to control was in the order of rye(13) > wheat. covered barley(11) > naked barley(99) > two-row barley(7): rye being the highest. In terms of the enzymatic activity and the physiotically adaptive metabolism during the processing leading to drought-resistance, the degree of drought-resistance of 5 species to water stress at seedling stage was shown to be in the order of wheat > rye > covered barley > naked barley > two-row barley.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.64-72
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• 2023

Biopolymer is a versatile material used in food processing, medicine, construction, and soil reinforcement. 𝛽-glucan is one of the biopolymers that improves the soil water content and ion adsorption in a drought or toxic metal contaminated land for plant survival. We analyzed drought stress damage reduction in sweet potatoes (Ipomoea batatas L. cv. Sodammi) by measuring the growth and major protein expression and activity under 𝛽-glucan soil amendment. The result showed that sweet potato leaf length and width were not affected by drought stress for 14 days, but sweet potatoes grown in 𝛽-glucan-amended soil showed an effect in preventing wilting caused by drought in phenotypic changes. Under drought stress, sweet potato leaves did not show any changes in electrolyte leakage, but the relative water content was higher in sweet potatoes grown in 𝛽-glucan-amended soil than in normal soil. 𝛽-glucan soil amendment increased the expression of plasma membrane (PM) H⁺-ATPase, but it decreased the aquaporin PIP2 (plasma membrane intrinsic protein 2) in sweet potatoes under drought stress. Moreover, water maintenance affected the PM H⁺-ATPase activity, which contributed to tolerance under drought stress. These results indicate that 𝛽-glucan soil amendment improves the soil water content during drought and affects the water supply in sweet potatoes. Consequently, 𝛽-glucan is a potential material for maintaining soil water contents, and analysis of the major PM proteins is one of the indicators for evaluating the biopolymer effect on plant survival under drought stress.

• Journal of Applied Biological Chemistry
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• v.59 no.3
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• pp.255-260
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• 2016

Reactive oxygen species (ROS) has been played a critical role in damage of DNA. Recently, many effort is focusing to develop the natural antioxidants for controlling ROS. Zelkova serrata, Ulmaceae, is close as plants which are planted in front of Korea villages. Although Zelkova serrata is familiar with Koreans, those of antioxidant activities and protective effects on oxidative DNA damage haven't studied. We demonstrated antioxidant activities and inhibitory effects on oxidative DNA damage of Leaf from Zelkova serrata with ethyl acetate fractions (EA) and hot water extracts (HW). Between the extracts, EA showed higher activities in 1,1-diphenyl-2-picryl-hydrazyl, 2,2'-azino-bis[3-ethylbenzthiazoline-6-sulphonic acid radical scavenging, $Fe^{2+}$ chelating and reducing power than HW. Also, those of total phenolic content are 56.63 and 51.61 mg/g respectively. In addition, ${\phi}X$-174 RF I plasmid DNA cleavage assay for inhibitory effect by oxidative DNA damage was both EA and HW has significant protective effect on oxidative DNA damage. The results suggested that leaf from Zelkova serrata with ethyl acetate fractions and hot water extracts have surpassing potential as natural resources with antioxidant and inhibitory effect on oxidative DNA damage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.227-227
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• 2017

This study was conducted to analyze the reduction of quality and ripening rate of rice due to submergence during ripening stage and identify the physiological cause. Korean japonica type rice cultivars, Nampyeong was used in the experiment. The following 7, 14 day after heading, they were then moved into submergence treatment facility and we conducted the tests under three different submergence conditions - T1(clear water and overhead submergence), T2(Muddy water and exposure of Flag leaf end ), T3(Muddy water and overhead submergence), and the treatment lasted for 4days. The decrease of ripening rate was most severe in T3 treatment at 7days after heading, and the decrease of head rice ratio was most severe in T3 treatment at 14days after heading. Meanwhile the starch synthesis was inhibited, as the supply of assimilation products was inhibited in grain during the submergence treatment. And in stem, sucrose content was increased because the soluble carbohydrates accumulated before heading were decomposed. These changes may be due to the consumption of respiratory substrate in anaerobic conditions and the inhibition of the production of photosynthetic products by light interception. In order to see what kind of reaction occurs at the molecular level, we examined the degree of RNA expression in grain, stem and leaf. First, the expression of rna associated with starch synthesis in grain was decreased in all submergence treatment. and especially Ospul(DBE) was more decreased in 14days after heading treatment than 7days after heading treatment. This difference can explain the result that the decrease of head rice ratio was more severe at 14days after heading. And in stem, the expression of rna associated with the supply of assimilation products was decreased in submergence treatment. Finally in leaf, the expression of rna(ADH, ALDH) associated with anaerobic respiration was increased, while the expression of rna associated with photosynthesis was decreased. These results of physiological analysis can used to develop the cultivation technique and to offer the information for breeding the cultivars with tolerant characteristics to submergence stress during ripening stage in rice.