• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.47-54
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• 1996

Soil pollution indices (SPI) were designed for estimating quality of soil polluted with arsenic and heavy metals. Applying the quality reference value of soil based on its multifunctional purpose was a key step. For considereing multifunctions of soil, soil was classified into 4 groups-agricultural land, residential area, recreational area, factorial site. Then, each concentration of arsenic and each of five heavy metals (Cd, Cu, Hg, Pb, Zn) in soils grouped was transformed to a mathematical value based on the soil quality reference value which may stand for ecological impact. Soil pollution score (SPS) was the addition of the 6 values transformed, and the range of the SPS was divided into 4 Soil Pollution Classes (SPC). The SPC 1, 2, 3, and 4 were SPS <100, SPS 100-200, SPS >200-300, and SPS >300, repectively. SPS and SPC were evaluated with the results of the data from employing the Soil Network of 1994. Based on the soil quality reference values, SPS and SPC of the Soil Network's data were transformed and classified, respectively. Then, SPS and SPC were compared with arsenic and the 5 heavy metal contents of their reference values resulted from the Soil Network's. From this method, soil quality of most of the Soil Network area was estimated to be healthy. However, ca. 3.0~4.0% of the Soil Network area was determined in a range of slightly and heavily polluted. As the mean value of SPS of the Soil Network's was 66.2 which indicates most of soil evaluated was healthy. When the SPSs of the data were divided into 4 groups of SPC, Class 1 (Good quality of soil), Class 2 (Need to be checked area 1), Class 3 (Need to be checked area 2) and Class 4 (Polluted area) were 87.0, 9.4, 2.4, 1.2%, respectively. Using SPI were comparable to those of heavy metal contents in soils, and would be comprehenve to determine the status of soil qulity. Methodology of the developing SPI would be applicable to the other soil pollutants such as organic and inorganics than arsenic and 5 heavy metals used here.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• The Plant Pathology Journal
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• v.39 no.2
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• pp.207-219
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• 2023

Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.1-7
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• 1972

Recently, young mulberry trees grown in the reclaimed hill land are frequently attacted by the die-bark and the buds of the trees developed poorly. In order to learn the cause of the injury mentioned above available boron content in the soils and the bark of young shoots have been analyzed. The results are as follow; Available boron content in the soil of the damaged mulberry fold was 0.3-0.20 ppm, against 0.39-49 ppm in that of healthy mulberry field, and boron in the bark of the damaged trees was 10.63-12.99 ppm, and 18.42-21.02 ppm in that of the healthy trees. The organic matter content and available boron content in soils showed a highly significant possitive correlation. The moisture content in percent in the soil of the damaged mulberry held was 11.16 and 14.22 in that of healthy mulberry field.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.121-126
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• 2000

Composition of fungal communities in three microhabitats such as soil, rhizosphere and rhizoplane were studied to understand the root environment of healthy and diseased plants in Phytophthora non-infested and infested fields, respectively. Samples were collected from the tomato- and red pepper-growing greenhouses in Kyungsang-Nam Province on April, 1999. Twenty-five species were isolated from each vegetation field using the dilution plate technique. There were a greater variety of species in infested fields than non-infested and in soils than in both rhizospheres and rhizoplanes. The number of species isolated were varied amongst the different microhabitats. A Trichoderma species was isolated only from non-infested fields.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.409-419
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• 2016

With increasing social concerns for healthy food, the studies on the cultivation of crops to increase accumulation of functional metabolites in crops have been investigated. Accumulation of the metabolites in crops is highly affected by various types of stress, such as nutrient deficiency, water deficit (WD), extreme temperature and UV-B radiation as well as their own life cycle. This review summarizes the previous studies on the effects of environmental stresses, especially WD and UV-B radiation, on accumulation of functional metabolites in crops. UV-B radiation and WD during specific period (mainly at maturation stage) activates the adaptation and/or defense system in crops, thereby increasing biosynthesis of the metabolites. Although WD and UV-B radiation tend to decrease in crop yield, the decrease can be compensated by the production of high value crops having high content of functional metabolites.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.333-341
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• 2010

The objective of our study was to investigate the major reasons for the different growth and visible injury on the needles of black pine growing in Ulsan and Yeocheon industrial complex areas, South Korea. After 12 years of growth, we collected climatic and air pollutant data, and analyzed soil properties and the physiological characteristics of black pine needles. Annual and minimum temperatures in Ulsan were higher than those in Yeocheon from 1996 to 2008. Ozone ($O_3$) was the pollutant in greatest concentration in Yeocheon, and whereas the $SO_2$ concentration in most areas decreased gradually during the whole period of growth, $SO_2$ concentration in Yeocheon has increased continuously since 1999, where it was the highest out of four areas since 2005. Total nitrogen and cation exchange capacity in Yeocheon soil were significantly lower than those of Ulsan. The average growth of black pine in Yeocheon was significantly smaller than that in Ulsan, and the growth of damaged trees represented a significant difference between the two sites. Photosynthetic pigment and malondialdehyde content and antioxidative enzyme activity in the current needles of black pine in Yeocheon were not significantly different between damaged and healthy trees, but in 1-year-old needles, there were significant differences between damaged and healthy trees. In conclusion, needle damage in Yeocheon black pine can be considered the result of long-term exposure to oxidative stress by such as $O_3$ or $SO_2$, rather than a difference in climatic condition or soil properties, and the additional expense of photosynthate needed to overcome damage or alleviate oxidative stress may cause growth retardation.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.15-19
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• 1974

A severe ginseng root rot disease was occurred and became widespraed in 1973 affecting the ginseng cultivating plot around Kangwha and Gimpo-Gun of Kyunggi province. Soil samples were collected from the area of Wolgot-Myun, Gimpo-Gun, Kuunggi-Do, 1974. We examined general fungi and Fusarium sp. in soil layers and also in different kinds of soil of respective diseased, uncultivated and healthy areas, and found the following results. 1. In the diseased and uncultivated area, the content of moisture, organic matter and silt was greater than in the healthy area. 2. Contray to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K,Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in the three types of soils. 3. General fungi were found in abundance in the diseased and uncultivated soils. It was observed that in all types of areas, general fungi reside in abundance in the rhizosphere, i.e., 10-15cm layers and that the closer the surface, the greater the numbers of fungi. 4. A great number of Fusarium sp. was found in the uncultivated area, and followed diseased and healthy areas. It was observed that in all types of areas, Fusarium sp. distributed in abundance in rhizosphere and that the closer the surface, the greater the numbers of Fusarium sp., with the numbers decreasing as the soil layers increase.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.97-104
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• 2016

Background: Rhizobacteria play an important role in plant defense and could be promising sources of biocontrol agents. This study aimed to screen antagonistic bacteria and develop a biocontrol system for root rot complex of Panax notoginseng. Methods: Pure-culture methods were used to isolate bacteria from the rhizosphere soil of notoginseng plants. The identification of isolates was based on the analysis of 16S ribosomal RNA (rRNA) sequences. Results: A total of 279 bacteria were obtained from rhizosphere soils of healthy and root-rot notoginseng plants, and uncultivated soil. Among all the isolates, 88 showed antagonistic activity to at least one of three phytopathogenic fungi, Fusarium oxysporum, Fusarium solani, and Phoma herbarum mainly causing root rot disease of P. notoginseng. Based on the 16S rRNA sequencing, the antagonistic bacteria were characterized into four clusters, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetesi. The genus Bacillus was the most frequently isolated, and Bacillus siamensis (Hs02), Bacillus atrophaeus (Hs09) showed strong antagonistic activity to the three pathogens. The distribution pattern differed in soil types, genera Achromobacter, Acidovorax, Brevibacterium, Brevundimonas, Flavimonas, and Streptomyces were only found in rhizosphere of healthy plants, while Delftia, Leclercia, Brevibacillus, Microbacterium, Pantoea, Rhizobium, and Stenotrophomonas only exist in soil of diseased plant, and Acinetobacter only exist in uncultivated soil. Conclusion: The results suggest that diverse bacteria exist in the P. notoginseng rhizosphere soil, with differences in community in the same field, and antagonistic isolates may be good potential biological control agent for the notoginseng root-rot diseases caused by F. oxysporum, Fusarium solani, and Panax herbarum.

• Korean journal of applied entomology
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• v.15 no.4 s.29
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• pp.169-178
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• 1976

The concentration of amino acids, total nitrogen, trehalose, lipids and the activities of respiratory, acid$\cdot$alkaline phosphatase, glutamic oxalozcetic transaminase and glutamic pyruvic transaminase during larval stage in Pine leaf gall midge, Thecodiplosis janensis Uchi. et Inouye were measured using Paper chromatographic method, micro-Kjeldahl method, Thin layer chromatographic method, Warburg's manometric method, Bessey-Lowry method and Reitman-Frankel method, respectively. Healthy specimens )yore chosen as samples of each larval stages; alrva in gall and larva in soil. Amino acids present in the alcoholic extracts were alanine, glutamic acid, glycine, histidine, methionine, proline, threonine, tryptophan and valine. The total nitrogen concentration reached to 31.348mg/g during the larva in gall and the larval stage in soil of the value was decreased to 29.027mg/g. The hemolymph sugar, trehalose value for larva in soil was about two times of the value for larva in gall. Total lipid, phospholipid,monoacylglycerol, triacylglycerol, sterol, free fatty acid and ester cholesterol were identified at larval stages in gall and soil. Triacylglycerol concentration reached high level in contrast with other lipid contents during larvae in gall and larva in soil. Free fatty acid, sterol except decreased lipids during larval stage in soil. Endogenous respiration, succinate of respiratory activities decreased at larval stage in soil compare with larva in gall. The activities of acid phosphatase decreased larval stage in soil but the activities of alkaline phosphatase increased remarkably. The activities of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase reached high level of the larva in gall.