• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.516-526
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• 2003

Thirty-six barley varieties including Korean modern and local varieties were tested for drought-tolerance in the field of plastic rain shelter, Drought treatment was initiated at initial tillering stage (March 27, 2002) by withholding irrigation and lasted until harvest. Soil water potential maintained at around -0.05㎫ in the control plot and varied from -0.05㎫ (at the initial stage of drought treatment) to -0.29㎫ in the drought treatment plot. At forty days after drought treatment, relative water content (RWC), osmotic potential (OP), osmotic adjustment (OA), and $^{13}\textrm{C}$ discrimination ($\Delta$) were measured and then plants were sampled for leaf area index (LAI) and dry weight (DW). Barley was harvested at maturity for determining DW, grain yield, 1000 grains weight and number of spikelet. The tested varieties revealed wide spectrum of drought tolerance. Dongbori-1, Chalbori, Changyeongjaerae, Samdobori and Weolseong 87-31 showed strong drought-tolerance while Songhagbori and Suwonmaeg360 showed weak drought-tolerance. The drought injury indexes (drought/control ratio) of DW and yield revealed significant positive correlation with leaf RWC in drought treatment plot and $\Delta$ in the control plot, but obvious negative correlation with leaf OP and OA under drought condition. In addition, all the drought indexes of OP, $\Delta$ and RWC showed obvious positive correlation with the drought injury indexes of DW, 1000 grain weight and yield. Thus, OP and RWC under drought condition and $\Delta$ under well-watered condition would be used as the evaluation criteria for drought- tolerance of barley genotypes. However, further investigation is needed for the relationship between $\Delta$ and drought-tolerance as the other reports were not consistent with our result.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.191-200
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• 1986

The study was conducted to screen paraquat-tolerant plant species among crops and weeds, using the response of plant like leaf disc discoloration, visual injury and dry weight in the presence of paraquat. Mechanism of paraquat-tolerance was investigated in strains of soybean through evaluating activities of superoxide dismutase and peroxidase and the multiplication of callus derived from soybean cotyledon. In crops, Kwanggyo has been selected as a paraquat-tolerant variety among soybean cultivars tested, and Hood as a susceptible one. In weeds, Polygonum aviculare, Chenopodium album and Pinellia ternata were evaluated as the paraquat resistant species, providing the possibility for the donor plant species for paraquat resistance. Activity of superoxide dismutase known to detoxify paraquat was markedly greater in Kwanggyo, a paraquat-tolerant cultivar than in Hood, a susceptible one. In addition, the similar response like superoxide dismutase was observed in peroxidese activity. The greater inhibition of callus multiplication was determined in Hood, a susceptible one than a tolerant one, Kwnggyo. Based on all the informations, it is strongly proposed that paraquat tolerance in soybean is due to destruction of $O_2^-$ by elevated concentration of superoxide dismutase in the tolerant cultivar.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.52-63
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• 1998

A novel quinolineoxadiazoles, substituted the carboxylic acid group with 1,2,4-oxadiazole radicle, of KSC-16960 and related compounds were evaluated to examine the herbicidal activity, crop injury and residual effect of after-vegetable crops compared with those of quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), of which use is now banned because of its residual activity to some succeeding vegetable crops. KSC-16960 showed 2- and 3-leaf stages of barnyardgrasses effectively controlled by more than 95 and 90%, respectively, at a rate of 6.25 g/ha. The dose of KSC-16960 controlled 4- and 5-leaf stages of barnyardgrasses by more than 90% were found to be 50 g and 100 g/ha, respectively. The selectivity of KSC-16960 between direct-seeded rice and barnyardgrass was approximately 2-fold higher than that of quinclorac when they were treated to the soil. The selectivity indices of KSC-16960 and of quinclorac between 1-leaf stage of direct seeded rice and 5-leaf stage of barnyardgrass were 44 and 23, respectively, and those between 1-leaf stage of direct seeded rice and 4-leaf stage of barnyardgrass were almost 2-fold higher. Application of KSC-16960 with bentazone exhibited an additive controlling effect on several weed species, but that of quinclorac exhibited an antagonistic effect. With pyrazosulfuron-ethyl, on the other hand, both application of KSC-16960 and quinclorac showed additive interactions. Under a greenhouse condition, the residual activity of KSC-16960 to succeeding tomato plants was approximately 4-fold lower compared to that of quinclorac. KSC-16960 could be substituted for quinclorac, if it will be made some more improvement for reducing residual activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.426-435
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• 2020

To determine the damages to waxy corn caused by low temperature weather, we investigated the relationship between the temperature and duration of low temperature treatment and the changes in growth characteristics during the recovery period after the treatments in different growth periods. Growth inhibition started in the low temperature group treated at temperatures below 5℃ for three days. The inhibition ratio (IR) was more than 22% or more in all sample groups. As the treatment duration increased and the Temperature decreased, the growth was more greatly inhibited than that in the control. The IR was the highest at 27% or more in the 2nd leaf stage group treated at below 5℃ for 5 days. The IR was in the order of 2nd leaf stage > 1st leaf stage > coleoptile. The IR during recovery was the highest in the 2nd leaf stage group treated at -3℃ degree for 7 days, nd the values were 82% and 98% for NDVI and Fv/Fm, respectively. Especially, all groups treated at -3℃ showed either no changes or decreases in the growth characteristics. As a result, growth inhibition increased as the temperature decreased, and as the duration of the low temperature increased. The degree of damage was in the order of 2nd leaf stage > 1st leaf stage > coleoptile. All early seedlings stopped growing and withered when exposed to temperatures at or below -3℃ for 3 days or more.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.479-487
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• 1996

This study was conducted to investigate the phytoprotective effects of uniconazole on $SO_2$ injury in P. occidentalis. The detoxification role of free radical scavengers such as superoxide dismutase (SOD) and peroxidase (POD) was also examined under the conditions of combined treatment with uniconazole and diethyldithiocarbamate (DDTC). Uniconazole drenching significantly reduced the occurrence of visible injuries. Though shoot length, leaf area, and T/R rate were greatly decreased by uniconazole application, the tolerance to $SO_2$ was enhanced through increased chlorophyll content and activities of SOD and POD. Spray of DDTC decreased the activity of SOD and POD resulting in the increase of visible injury. Plant tolerance to $SO_2$ induced by uniconazole application was reduced by the additional application of DDTC. These results indicate that plant tolerance to $SO_2$ induced by uniconazole is associated with the reduction of vegetative growth as well as the increase in free radical scavengers such as SOD and POD.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.229-233
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• 1981

This study was to investigate ornamental trees injuries at the Tobong ornamental tree farm, which is located in Uichongpu City, Kyonggido. The injury was caused by $SO_2$ gas from the smoke of the vicinal factories. The results obtained are as follows: 1 The total concentration of sulfur in leaves was increased with incerased degree of injury The most severe injuries were found at the distance between 70-120m from the western boundary of the Tobong ornamental 4ree farm with a highest concentration of total sulfur at $0.5-0.6\%$. This means the injuries caused by the acute injury and the temperature changes. 2. Significant differences were found between normal and injured portion of the same trees in Juniperus chinensis. 3. Anatomical study of the leaf tissues, showed the plasmolysis occured both in spongy and epidermal cells, leading to shrinkage and destruction. An intercellular space and stomatal periphery became wider.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.695-703
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• 2014

We experimented with the effect of oleic acid and its appropriate concentration to prevent powdery mildew eco-friendly in a cucumber greenhouse cultivation. 'Baekbongdadaki' (Nongwoo Bio. co. Korea) was treated in the plastic greenhouse at Sangmyung University. We treated four levels of concentration of oleic acid, which were 0, 2000, 4000, 6000, and 8000 ppm. There were investigated diseased severity, diseased leaf area, control value, and pesticide injury. The degree of control values by oleic acid treatments was investigated at 3 days after treatment. The recurrence of powdery mildew was checked for 55 days. The day and night temperature in the greenhouse were controlled to 23 and $15^{\circ}C$ respectively. The humidity inside the greenhouse was not controlled to prevent outbreak of the disease. From the experimental results, oleic acid was very efficient to control powdery mildew. 2000 ppm of oleic acid was shown to be the most control efficiency without any pesticide injury. The recommended method to treat it was to spray three times every 3 weeks.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.607-613
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• 2014

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell $Ca^{2+}$ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at $-3^{\circ}C$, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of $Ca^{2+}$ from the intracellular space. Then, the imported $Ca^{2+}$ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of $Ca^{2+}$ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

• The Korean Journal of Community Living Science
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• v.28 no.4
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• pp.537-546
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• 2017

This study was performed to determine the hepatoprotective effects of ethanol extract of loquat leaf (LL) on alcohol-induced liver damage in rats. Sprague-Dawley rats (n=32) were divided into the following four groups: normal group (NOR), ethanol administrated group (ET), ethanol plus LL 200 mg/kg BW/day administrated group (ET-LLL), and ethanol plus LL 400 mg/kg Bw/day administrated group (ET-LLH). Body weight gain and food intake of the ET group were significantly reduced compared to those of the ET-LLL and ET-LLH groups. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) activities elevated by ethanol administration were significantly reduced by LL administration. Serum triglyceride (TG) and total cholesterol (TC) contents and hepatic TG and TC contents of the ET group were significantly elevated compared to those of the NOR group. However, TG and TC contents in the serum and liver were significantly reduced in the ET-LLH group. Hepatic glutathione (GSH) contents of the ET-LLL and ET-LLH groups were significantly elevated, and hepatic thiobarbituric acid reactive substances (TBARS) contents were reduced compared to that of the ET group. Taken together, these results suggest that LL may have a possible protective effect on the improvement of hepatic injury by ethanol administration.

• Korean Journal of Environmental Agriculture
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• v.7 no.1
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• pp.52-57
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• 1988

This study was carried out to investigate the specific activity fo peroxidase(POD) in conjunction with the phytotoxic effect of the tolerant soybean(Glycine max Merr.) and the susceptible crabgrass(Digitaria adscendens(L.) Scopol.) to acifluorfen. The POD activity increased during the growth of soybean and crabgrass seedlings. But after the foliar application of acifluorfen, the POD activity in the treated leaves was considerably higher than in controlled leaves, suggesting that soybean had higher tolerance to acifluorfen with growth. All the treated soybeans recovered from herbicidal injury in 14 days after treatment, while all the treated crabgrasses were dead with extreme necrosis and leaf burning. It was measured that the POD activity of crabgrass increased abruptly in 1 to 2 days after treatment and then significantly decreased in 5 days.