• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.49-59
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• 1981

In order to elucidate the process of plant succession of the Japanese red pine forests caused by pine gall midge, Thecodoplosis japonensis, in the area of Chungbuk and Kyongbuk, 12 study plots, 4 plots from each three districts, were set up. Districts A (Cheongwon)not attacked by this insect, as the check, District B(Gumi) in which the insect outbreak occured 5 years ago, and District C(Yeongdong)in which the insect outbreak occured 10 years ago, were sampled. The surveyed were some environmental factors, the number of woody plants, relative density, relative dominance values, species composition of plots by layer(upper, middle and ground), importance values, species diversity, similarity and dissimilarity index, etc. The results obtained are summarized as follows: The accumulation of litter on the ground was increased with the lengthening the insect damage duration. Through the crown opening and litter accumulation, the light intensity, temperature condition and soil moisture and nutrient content might be altered. According to the changes of species composition were forced. In general, the Genus Quercus, as a compensation species, has sprung up. The relative importance values for Q.aliena, Q.serrata, and Q.variabilis were significantly increased in the insect infested forests. 2. the stand structure and species composition of the insect attacked forest about 5 years later after the outbreak become complex and diverse. However, since this time, the simplicity of these regards become restored up to 10 years after the outbreak. 3. As the synthetic analysis of plant succession process, the relative values calculated from the relative density and the relative dominance values shown the dominant status of Genus Quercus in the heavily damaged forests. In addition, Genus Rhododendron and Genus Lespedeza with higher frequency become the ground vegetation components. They were gradually increased along the time elapsing after the insect out-break. 4. The differences in connection with the soil moisture contents, the organic matter contents which might give some influences to the vegetation change were hardly recognizable statistically among the studied plots by three district groups. We estimated that the annual mean precipitation and the annual mean temperature did not operated any meaningful effects on the vegetation alteration among plots between districts.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.389-398
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• 1984

The effect of N forms ($NO_3{^-}-N$, $NH_4{^+}-N$) and concentrations (4, 8, $16meq/{\ell}$) which were changed at head formation stage on the tip-burn incidence of chinese cabbage was studied under the three levels (0, 8, 16 meq/l) of Ca. All of the plants grown on $NH_4{^+}-N$ showed the symptoms of tip-burn and low yields regardless of Ca levels. Roots of plants grown on $NH_4{^+}-N$ were severely damaged. The pH of the leachate from $NH_4{^+}-N$ pot was decreased to below pH 5. Plants which had been grown on $NH_4{^+}-N$ before the head formation stage, but changed to $NO_3{^-}-N$ were recovered from abnormal growth. But, the reverse showed the tip-burn symptoms. $NH_4{^+}-N$ treatments increased the T-N contents, but lowered K and Ca contents of inner leafblades. Icreased applications of Ca did not affect the T-N and K contents of the inner leafblades. $NH_4{^+}-N$ suppressed Ca translocation into the inner leaves from outer leaves after the head formation stage, but $NO_3{^-}-N$ accelarated it. Ca contents were much lower in leaves showing tip-burn symptoms than in healthy leaves. Internal rot which is a tip-burn symptom occuring after head formation were noted in plants applied with high concentration of $NO_3{^-}-N$ both before and after the head formation stage. Ca contents correlated well with the rates of Ca application, but there was no correlation between ca conents and internal rot incidence. Chinese cabbage tip-burn is not caused by Ca deficiency, as is commonly believed, but rather by the water stress (95% water contents in $NO_3{^-}$-fed plants, 91% in $NH_4{^+}$-fed plants) resulting from root damage caused by ammonium toxicity. Internal rot is also caused by excess applications of nitrogen, and is unaffected by calcium levels.

• Korean Journal of Soil Science and Fertilizer
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• v.13 no.1
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• pp.39-44
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• 1980

To study the effects of sulfur dioxide on the plant; Barly, wheat, soybean sweet potato, cucumber, egg plant, red pepper, tomato, lettuce, water melon, castor bean, grape and lily were exposed to the different levels of sulfur dioxide gas(0.1, 0.25, 0.50, $1.0mg/{\ell}/hr$) The symptoms of damage, ratios of destroyed leaf, sulfur content and absorption amounts of the gas by leaves were investigated 1. According to the increasing concentration of the gas ratios of destroyed leaf were increased in all plants. The ratios of destroyed leaf were shown by egg plant at $0.1mg/{\ell}/hr$ of $SO_2$ were 30 percent, and no visible injuries were shown by the wheat potato, castor bean, water melon, lily at $0.25mg/{\ell}/hr$. 2. Gray and red brown spots between the vein nerve shown by barly and wheat leaf; leaf burn by soybean, potato, sweat potato, castor bean, egg plant, red pepper, tomato and grape; leaf withering from the leaf tips by the lettuce, water melon, lily. 3. The volums of the gas absorption by cucumber, egg plant, red peper, castor he an were more than $10{\ell}/hr$, however less than $2{\ell}/hr$, be lettuce, water melon, grape, barly and wheat. 4. According to the increasing concentration of sulfur dioxide gas, sulfur contents in leaf were increased in all plants, however volums of absorption gas were decreaed. 5. According to the increase of sulfur content in leaf, ratios of destroyed leaf were increased. 6. Positive correlation was shown between total and water soluble sulfur content in leaf.

• Journal of Bio-Environment Control
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• v.3 no.2
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• pp.106-118
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• 1994

This study was conducted to analyze the effects of fluctuations in temperature, light intensity and soil temperature on the growth of red pepper seedlings in the nonheated plastic houses with various number of layers and in the open field. Relationship between the optimal environment and the growth of seedlings was discussed, and the maximum and minimum outdoor temperatures in Kwangju area from 1941 to 1985 were analyzed. The results obtained were as follows; 1. The minimum temperature in tunnel with quadruple coverings of P. E. film from December 20 to February 25 was decreased to 5$^{\circ}C$ mostly, where the exposure to chilling temperature could not be avoided during this period. The maximum temperature was increased to 33$^{\circ}C$ mostly and 42$^{\circ}C$ in peak, where some ventilation was needed. 2. The diurnal differences of inside temperature, increasing with number of layers, were 16 to 38$^{\circ}C$, while those of outside temperature were 5 to 1$0^{\circ}C$. 3. The cold injury in the quadruple coverings during winter occurred all the times below 12$^{\circ}C$ and as many as 200 times over 3$0^{\circ}C$, while effectiveness of thermal insulation in the multilayered nonheating plastic houses were clearly proved. 4. The inside light intensity was markedly reduced with the increment of layers and the minimum light intensity fallen down below the light compensation point for the growth of red pepper plants regardless of the number of layers. 5. Until 10 a. m., the temperature in the daytime during December 20 to mid - February showed below 10 to 12$^{\circ}C$ which was the limiting temperature for the growth of red pepper seedlings. After 4 p. m., the light intensity was sharply reduced despite of the air temperature kept over 12$^{\circ}C$. Therefore, limiting factors for the growth of red pepper seedlings were the temperature before 10 a. m. and the light intensity after 4 p. m. 6. The minimum soil temperature in quadruple coverings showed around 1$0^{\circ}C$ where the physiological damage for red pepper seedlings might be occurred. 7. The minimum outdoor temperatures from 1941 to 1985 was -19.4$^{\circ}C$, observed in the 5th January.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.213-219
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• 2007

It has been well established that aluminum (Al) inhibits root tip growth rapidly in acid soil. We report the correlation between Al induced growth inhibition and impaired $H^+-flux$ in mung bean (Vigna radiate L. cv. Kumsung). The root growth inhibition was dependent on Al concentration (0, 10, 25, 50, $100{\mu}M$) and exposure time (12 and 24 h). Using Hematoxylin staining, it was observed that the root damage was occurred preferentially in regions with high Al accumulation. Using the pH indicator, it was shown that the surface pH of root tip was strongly alkalized in the control whereas changed only slightly in the $50{\mu}M$ Al-treated root. The $H^+-ATPase$ activity of plasma membrane vesicles was inhibited by 56% in the Al-treated roots compared to control root. Decrease in the amount of the plasma membrane $H^+-ATPase$ (100 kDa) translation in the plant roots under Al stress was demonstrated by Western blot analysis. These results indicate that the dynamics of $H^+-flux$ across the root tip play an important role in root growth under Al stress.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2177-2190
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• 1971

This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

• The Korean Journal of Mycology
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• v.12 no.3
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• pp.105-110
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• 1984

Seven seed samples of corn obtained from Kangweon Provincial Office of Rural Development, Kerea were tested for seed-borne fungi, and found that all the samples tested were infected with Fusarium moniliforme to an extent of $6.0{\sim}79.5%$. Severely infected seed samples showed poor germination on blotter. Seed component plating showed that the fungus present not only in tip caps, pericarps and endosperms, but also in embryos. Heavy infection of the fungus caused severe seed rot and seedling blight in soil, but the damage was not severe and many plants grew without any symptoms when the seeds with light infection were sown in soil. However the fungus was frequently detected from inside of the stems of healthy looking seedlings. The results indicate that the fungus transmit from seed to plant systemically. In inoculation experiments, the fungus produced stem rots on corn plants of 110 days old. The cultivar of Hwangok 3 was revealed more susceptible to the fungus than that of Suweon 19.

• Journal of Korean Society of Forest Science
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• v.58 no.1
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• pp.34-40
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• 1982

Main consideration of this trial is to know whether the planting work should be possible to do not only in the early spring but also in the summer or autumn, for giving the guide to get the work plan and to broaden the employing season of the skilled forest worker. Seedling of Pinus koraiensis, Larix leptolepsis, Pinus rigida, Pinus rigida${\times}$ P. taeda(wind) and Chamaecyparia obtusa as the test species had been planted in 15 days interval from the middle of March to the end of November. The seedling survival was investigated in the spring time of coming year because the winter damage could be problems. At the same time the climate data was measured daily and the shoot growth of test species were also measured in other near plantation at 15 days interval to know the influence to survival. From these results the spring and autumn planting is showing the good survival and the summer planting seems to give the difficulties. The spring planting in the southern temperate zone could be stared earlier as the end of February or beginning of March because the soil temperature are increasing up more $5^{\circ}C$ from this time. But the summer planting from the beginning of May until the end of August in better to avoid with excluding specially the good season of rainfall distribution because of the shoot growth of green confer seedling and the leave sprouting of Larix leptolepsis are so vigorously growing up from the begining of May and its wood structure is too weak to compensate the water loss. But among the test species Pinus koraiensis and Chamaecyparis obtusa have more possibility to plant in the summer season. The autumn planting seems to be very reasonable to accept newly in the trial region. This may be the reasons of still high soil temperature to grow the seedling root and of hardened school to resist from the dry winter wind. But it will be carefully that the strongly exposured site could be to avoid for the autumn planting in case of specially Pinus rigida${\times}$P. taeda and Chamaecyparis obtusa. From these discussion the guide table 1 for planting season with the test species is proposed and can be used for planing and employing in the trial zone.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.25-25
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• 2014

Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide ($ClO_2$), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous $ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of $ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm $ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using $ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of $ClO_2$. Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at $30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous $ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of $ClO_2$. Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.107-113
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• 1973

A pot experiment on paddy rice was carried out to investigate the effect of temperature after heading with application of phosphate, potash and silica on the yield and nutrient uptake. The results obtained are as follows: 1. The Grain yield was greatly affected by temperature during ripening. The yield at $20^{\circ}C$ and at $15^{\circ}C$ decreased to 62.3% and to 37.2% of that at $25^{\circ}C$ respectively. However, the application of phosphate, potash and silica at transplanting increased the grain yield even at low temperature of $15^{\circ}C$. 2. Percentage of ripened grain and weight of 1,000 grains decreased with decreasing temperature but they were increased by the application of phosphate, potash and silica at the low temperature of $15^{\circ}C$. 3. The grain filling rate was fast in the early stage of ripening at high temperature while it was fast in the later stage at low temperature. Low temperature damage was severe in the early stage of ripening. 4. Accumulation of carbohydrate in the grain was small at low temperature of $15^{\circ}C$ and the application of phosphate, potash and silica was effective to increase carbohydrate content in the grain at low temperature. 5. The content of T-N and $P_2O_5$ in straw grown at low temperature were high whereaas those of $K_2O$ and $SiO_2$ were low which were increased by the application of potash and silica. 6. There was a positive correlation between the grain yield and rate of ripening, 1,000 grain weight, contents of $K_2O$ and $SiO_2$, $K_2O/N$ and $SiO_2/N$ ratio, but a negative correlation between grain yield and contents of T-N and $P_2O_5$ in the straw at harvesting stage. 7. Ripening rate and weight of 1,000 grains showed a significant positive correlation with $K_2O$, $SiO_2$, $K_2O/N$ and $SiO_2/N$ ratio in the straw. Further, there was a negative correlation between ripening rate and the contents of T-N and $P_2O_5$ but a positive correlation between weight of 1,000 grains and these elements.