• Korean journal of food and cookery science
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• v.17 no.6
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• pp.583-588
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• 2001

In this study, the differences in the contents of vitamin C and minerals in perilla leaves were compared according to the age of leaf and storage conditions. The content of vitamin C in perilla leaves the younger the perilla leaves, the higher the content of vitamin C: Vitamin C content of mature leaf at the lowest part of the stem was 63.7mg/100g, and that of young leaf at the top of the stem was 129.0mg/100g. However, the contents of Ca and Fe by the leaf age were in an opposite tendency with vitamin C: Ca content of the leaves at the lowest and the top part of the stem were 449.4 mg and 311.8mg/100g, respectively. But, the contents of Na and Mg were poor in mature leaf, and the content of K showed no particular difference according to leaf age. When stored at 5$^{\circ}C$, residual rate of vitamin C content was 92.56, 81.52 and 77.05%, after stored 1, 5 and 10 days, respectively. In the case of 20$^{\circ}C$, residual rate of vitamin C was 85.80, 79.90 and 72.53%, respectively. When stored at 5$^{\circ}C$, Ca content in perilla leaves was in the range of 348.93∼408.81mg/100g, and at 20$^{\circ}C$, the content of Ca was 360.26∼392.25mg/100g. Storage time and temperature did not make a significant difference in the mineral content of perilla leaves.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.69-75
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• 1998

Responses of tobacco(Nicotiana tabacum cv. Xanthi) leaves of different age to diphenyl ether herbicide oxyfluorfen were evaluated with respect to cellular leakage, chlorophyll loss, and membrane lipid peroxidation. When tobacco leaves of different age were incubated under light condition at $25^{\circ}C$ following 12hr dark incubation. Significant electrolyte leakage from the treated tissues into the bathing medium occurred. The change of electrolyte leakage was proportional to the oxytluorfen concentration and the duration of light exposure to the tissues. Electrolyte leakage from the tissues treated with oxyfluorfen was highly dependent on the leaf age. From the tissues of younger age, more electrolyte leakage occurred and lag period was greatly reduced. Chlorophyll loss and membrane lipid peroxidation, as measured by malondialdehyde production, caused by oxyfluorfen treatment were also dependent an the age of treated leaf tissues. In conclusion, physiological responses of tobacco leaves to oxyfluorfen greatly varied with the age of treated tissues, and thus tobacco plants could be used as appropriate materials for studying the mechanisms of tolerance to diphenyl ether herbicides.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.298-299
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• 2005

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.63-71
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• 1977

${\times}$Populus albaglandulosa has been needed optimum stand density according to various site and its wood usage. It is assumed that optimum stand density can be estimated by investigating of response of ${\times}$P. albaglandulosa to the light factor of stand. For that reason, the photosynthesis of ${\times}$Populus albaglandulosa grown under the controlled planting density was studied in relation to its leaf age by the aid of the Infrared gas analyzer. Rate of net photosynthesis was smaller in matured leaves than young leaves below $8^{\circ}C$, while, it was larger than young leaves above $8^{\circ}C$. Temperature for the maximum net photosynthesis of young leaves and old leaves was about $30^{\circ}C$ and $25^{\circ}C$ respectively. Saturated light intensity varied slightly as leaf age from 28 Klux to 35 Klux, but net photosynthesis rate in the range of light intensity showed deep differences. Old leaves marked the lowest rate, $1.6\;CO_2\;mg/dm^2/hr$, young leaves marked the medium rate, 1.7 to $2.2\;CO_2\;mg/dm^2/hr$, and matured leaves marked the most efficient photosynthesis, 2.9 to $3.5\;CO_2\;mg/dm^2/hr$. Young leaves of 5 days old had the highest light compensation point, while matured leaves of 35 days-old had the lowest point. Rates of dark respiration in both young leaves and old leaves were higher than that of matured leaves. Trees which were planted at space $80cm{\times}80cm$ showed productive assimilation function over the one-third of height where relative light intensity is 35%.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.486-497
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• 1994

The objective of this study was to examine the effects of air pollution on Pinus thunbergii forests surrounding Sasang industrial complex in Korea. The injury index, contents of chlorophyll and mineral elements, and concentrations of water soluble sulfur in needles were investigated at sample plots surrounding industrial complex and compared with those of control far from industrial complex. The results obtained are as follows ; 1. Discoloration of Pinus thunbergii needles was severe in the vicinity of industrial complex, and the older needle age classes was the more severe its injury appeared. Injury index was increased in the vicinity of industrial complex. 2. Water-soluble sulfur concentration was high in the vicinity of industrial complex at all of needle age classes, and those of all plots were higher than that of control. 3. Chlorophyll a contents were lower at surrounding industrial complex than that at control. It was supposed that chlorophyll a was destroyed by air pollutants. Total chlorophyll contents and content ratio of chlorophyll a to b were influenced by decrease of chlorophyll a contents. 4. Phosphorus contents in needles were decreased even in remoted regions with the increase of needle age classes. Colcium contents in needles were decreased near industrial complex at all needle ages classes. 5. There were negative correlation, between injury index and chlorophyll contents, injury index and calcium contents, and there were positive correlation between injury index and calcium contents. 6. Cluster analysis was carried out to divide the injured regions on sample plots. As a result of the analysis, there were devided 3 regions, severe regions(1-8 plots), medium regions(9, 10, 11, 12, 15, 17 plot), slight(13, 14, 16, 18, 19 plot and control). 7. The cross section of visible injured needle showed the destruction of mesophyll cell, sclerenchyma cell in the outside of resin duct and endodermis, partially.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.111-121
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• 2010

Differential tolerance to protoporphyrinogen oxidase (Protox)-inhibiting herbicides, oxyfluorfen was observed between leaf ages in squash. Physiological responses to oxyfluorfen, including leaf injury, cellular leakage, accumulation of tetrapyrroles, and antioxidative enzymes activity, were investigated in leaf age classes of squash to identify mechanisms of oxyfluorfen tolerance. Leaf 1, 2, and 3 injuries for Joongangaehobak were >10,000, 1,286, and 1.6-fold higher than that of leaf 4, after treatment of oxyfluorfen. On the other hand, leaf 1, 2, and 3 injuries for Sintowjahobak were 725, 366, and >0.6-fold higher than that of leaf 4, after treatment of oxyfluorfen. However, in contrast to oxyfluorfen treatment results, leaf injury of squash leaf 4 treated with paraquat was much smaller than in leaves 1, 2 and 3. Electrolyte leakage from the tissues treated with oxyfluorfen was higher in the youngest leaf (Leaf 4) than in the older leaves 1, 2, and 3. Differential leaf response to oxyfluorfen of squash appears to be due in large part to differences in protoporphyrin IX (Proto IX), Mg-Proto IX, and Mg-Proto IX monomethyl ester accumulation in treated leaves. In contrast, leaf 4 had higher activities of superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase than leaf 1 after treatment with oxyfluorfen. However, the induction in antioxidant activity in leaf 4 was not enough to overcome the toxic effects of a Protox inhibitor, oxyfluorfen, so the leaf eventually died.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.252-269
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• 1994

This study was conducted to the early diagnosis of injuries on needles of conifer by acid rain and air pollutants in metropolitan area, Korea. It was executed to calculate of injured index, contact angle measurement, nutrient content analysis in needles, analysis of soil chemical properties from June 1990 to June 1991. The sensitive species (Picea abies, Abies holophylla) for acid rain and air pollutants were used as the study materials. And the results from this study were as follows : Degree of Injured index was divided into three groups in June 1990. The first group (not injured sites) was Kwangnung and Yangpyung. The Second group (slight injured sites) was Inchon, Boramae Park, Kwachun, Seoul Women's Univ., Anyng, and Yangsuri. The third group (serious injured sites) was Namsan, Seoul City Univ., Children's Park, and Kumgok Royal Tomb. But, Inchon, Kwachon area were changed from slight injured areas to serious injured areas in December 1990. As time goes on, the degree of injured gets worse. In contact angle analysis, value of December 1990 was lower than that of June 1990, especially, that of two-year-needle were lower than of one-year-needle. The correlation between injured Index and contact angle was significantly negative. In the result of needle nutrients analysis of Picea abies, Abies hozophylla, Ca, Mg, K contents was higher in December 1990 than that in June 1991 and that of one-year-needle were prominantly higher than that of two-year-needle. In case of wax quantity analysis in injured area, the older the leaf age is, the smaller the contented wax quantity is. In injured area, the higher a leaf age is, the much that of index is. As a result, the method of analysis referred in the former, is applied by a complementary cooperation. That of method is done sustainably in the future, the correct results will be expected.

• Research in Plant Disease
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• v.10 no.2
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• pp.112-116
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• 2004

This study was carried out to investigate factors affecting disease development of rice brown spot caused by Cochliobolus miyabeanus in the field and under the greenhouse conditions. In normal paddy fields, the pathogen was more frequently isolated from dried rice straws than wet straws after overwintering. The pathogen was also readily isolated from wet rice straws of salty paddy fields although infection rate of the fields was low. The disease symptom was first observed at 2 to 3days after inoculation when the seedlings were kept for 6 hours in dew chamber. The number of lesions peaked at 14 hr incubation in cultivars Chucheongbyeo and 24 hr incubation in cultivar Daesanbyeo and Tetep. Sixty three-d-old seedlings were more susceptible than 21 to 49-d-old seedlings regardless of cultivar. There was some difference in number of lesions observed, but the lesions were evenly spread regardless of leaf position. Light on the rice seedlings at 3,000 lux or 6,000 lux showed more severe symptoms than those in the dark.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.38-45
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• 2007

Laboratory and greenhouse experiments were conducted to determine the herbicidal effect of two types of ${\delta}$-aminolevulinic acid (ALA), microbiologically-produced ALA (Bio-ALA) and synthetically produced ALA (Synthetic-ALA), on plant growth and chlorophyll content of Chinese cabbage. ALA effect on early plant growth was greatly concentration dependant, showing significant inhibition at higher concentrations. Both pre- and post-emergence application of ALA exhibited significant degree of photodynamic phytotoxicity. Older plants with many leaves were more tolerant to ALA than younger plants, showing less injury. No significant difference in herbicidal activity of two types of ALA, Bio-ALA and Synthetic-ALA, on plant height and chlorophyll content of Chinese cabbage was observed. However, residual biological activity and physico-chemical properties of Synthetic-ALA were more stable than those of Bio-ALA. Our results suggest that ALA had herbicidal potential with both pre- and post-emergence application, and that the chemical may be a valuable mean of eco-friendly weed control based on natural microbial substance.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.101-106
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• 1994

Factors affecting phytotoxicity of dithiopyr in rice such as transplanting depth, seedling age, soil texure were examined and mechanism of phytotoxicity in rice was also determined by absorption study of $^{14}C$-dithiopyr in rice seedlings under above conditions. Rice injury was occurred in shallow transplanting depth, young rice seedlings and sandy soil conditions. Higher amount of dithiopyr was absorbed in rice at shallow transplanting depth and sandy soil conditions which may related to phytotoxicity of dithiopyr.