• Research in Plant Disease
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• v.21 no.1
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• pp.40-43
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• 2015

Bacterial pustule of soybean is caused by Xanthomonas axonopodis pv. glycines, one of the most important diseases in soybean. The symptom of bacterial pustule is mainly distributed around leaf veins. However, the reason has not been known. In order to determine pathosystem of bacterial pustule in leaf, soybean leaves were collected and observed using scanning electron microscopy (SEM) and light microscopy. Many hairs were observed at abaxial sides of the leaf, few hairs were observed at tissue around the leaf veins. In addition, unidentified bacterial cells and dusts at the no hair part near veins were observed. In the inoculation assays, the cells of X. axonopodis pv. glycines were observed near leaf veins. The imprint of underside of soybean leaves inoculated with X.axonopodis pv. glycines on PDA showed that the growth of bacteria around veins was observed but no bacterial growth at the part with leaf hairs. Our data demonstrated that soybean leaf hairs play an important role as a physical barrier for structural resistance of soybean against bacterial pustule pathogen.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.68.2-69
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• 2003

Genetic transformation carried out to induce the pathogenicity mutants from the two isolates, Elsinoe fawcettii R-34 and MUD of citrus scab fungus to hygromycin resistant by transferring plasmides (pUCATPH) that contain hygB gene. We produced protoplast for transformation by using of combinations of available enzymes including ${\beta}$-D-glucanase, ${\beta}$ -glucuronidase, Iyticase and driselase. The protoplasts regenerated at 64 $\mu\textrm{g}$/ml of hygromycin B but not 128 $\mu\textrm{g}$ in sensitivity test to identify the concentration of useful marker for the selection of transformants. Approximately 1200 and 67 hygromycin resistant isolates from strain R-34 and strain MUD, respectively, were isolated on PDA added with 200 $\mu\textrm{g}$ /ml of hygromycun B. Fifty seven and 4 of hygromycin resistant isolates from strain R-34 and MUD, respectively, did not produce necrotic lesions on the leaf in detached-leaf assay. Finally, 9 isolates were isolated from strain R-34, and these Isolates produced non or very few symptoms on seedlings of citrus in greenhouse pathogenicity test. And it's very interesting that some isolates produced melanose-like symptom on very young leaves which it was not typical symptom and somtimes produced on only expanded leaf.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.1.2-6
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• 1990

The purpose of this experiment was to investigate boron deficient symptom of sugar beet. Sugar beet affected by boron deficiency was anatomized and observed by microscope and electron microscope. The sugar beet plants affected onboron deficiencyu with water culture and those of the experimental farm alike contained a small amount of boron. The symptom of boron deficiency began to show dark-brown lines at the ventral suface of the basal part of petiole and then, in the ridge of young leaf, growing point became darkened due to necrosis. The leaf blade was wrinked severely and finally the growth was stunted. The boron deficiency began with necrosis of the epidermis of the ventral surface of the basal part of petiole, and parenchyma under it. Necrosis and disintegration of the ridge of young leaf began to take place and were expanded gradually. Electron microscopic examination of boron deficient sugar beet plants revealed that chloroplasts degenerated, and appeared to contain larger amounts of starch, also observed larger number of osmophilic granules. And they peculiarly were found polyhedral crystals in the certain deficient chloroplasts.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.409-414
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• 2009

In 1970's Black locust(Robinia pseudoacacia) had been widely planted Korea as an important forest greening species for erosion control afforestation. Since 2000, however, the tree's leaf-yellowing symptom has often been observed at a limited region and then spreaded out over the country in 2006. This study was conducted to study soil physiochemical properties of black locust stands with and without the leaf-yellowing symptom in Osan, Gyeonggi province. Most of soils in sampling sites were mostly slightly eroded, dry, and moderately dry. Available soil depth(16cm) and total soil depth(26cm) in leaf-yellowing (LY) site were significantly lower than in non leaf-yellowing (Non-LY) site's soil depths which were 30cm and 56cm, respectively. And solid phase proportion and bulk density in soils were lower in LY site than in non-LY site soils, while soil liquid phase proportion was also low. It could reflect that LY site soils might have a lower air and moisture movement in the rhizosphere of black locust stand compared with non-LY site soils. Soil acidity in both sites was very strong acid, soil pH (4.42) of LY site was slightly lower than non-LY site's (pH 4.54). Content of available phosphorous, exchangeable $Ca^{2+}$ and $Mg^{2+}$ and percent base saturation were less than LY site. These results indicated that soil physiochemical condition in LY site, more deteriorated than non-LY site, should adversely affect the retention and supply capacity of soil nutrients and moisture. Therefore the black locust may be more sensitive to other environmental stresses.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.71-76
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• 1976

Field experiments were conducted to study the effect of amendments such as lime and organic matter for mulberry trees on the newly reclaimed sandy loam soil for three years. The results are summarized as follows. 1. Compared to the N.P.K check plot with treatments, leaf yield was increased by 20 to 80%. Leaf yield was higher in the order of NPK+magnesia lime < NPK+compost > NK+fused phosphate NPK+green manure > NPK+barley straw> NPKplot. 2. Mulberry leaf yield showed high significant positive correlation with total weight and volume of root, length and number of wattles and the content of CaO or MgO in leaf respectively. 3. It is known that dead part sympom of top branch during cold season is associated with unbalance magnesium to potassium in mulberry leaf. It is estimated that such symptom was deminished when the ratio of $K_2O/MgO$ in leaf becomes 6.0 or higher. 4. In establishing a mulberry field on hilly reclaimed soil, application of magnesium and calcium with compost was essential but higher amount of potassium fertilizer should be followed in order to prevent dead part symptom of top branch of mulberry trees.

• Korean Journal of Medicinal Crop Science
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• v.23 no.2
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• pp.150-154
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• 2015

Physiological disorders such as symptoms in leaf colored with brown spots are so many occurred in ginseng garden cultivated with paddy soil. This study was carried out to inhibit the symptoms of brown-colored leaf in 3-year-old ginseng by fertilizing calcium hydroxide [$Ca(OH)_2$] of 100 ~ 400 kg per 10a on paddy soil before transplant of seedling. Soil pH was rapidly increased, while Fe was decreased in soil by the increase of application level of calcium hydroxide. Soil pH was increased from 4.53 to 6.18 when calcium hydroxide was fertilized at level of 100kg per 10a. The content of Fe in ginseng leaf was decreased more than the control by fertilizing calcium hydroxide in soil. Ratio of brown-colored leaf and plant height and leaf area were decreased by the increase of calcium hydroxide. Ratio of survived root and yield of root showed the peak at the application level of 100 kg per 10a, and both of them were gradually decreased by the increase of calcium hydroxide. The decrease of missing plant rate above the application level of 200 kg per 10a had a negative effect on the decrease of yield of root.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.393-396
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• 1998

The characteristic Ramularia type conidia of Mycosphaerella nawae were formed on naturally infected leaves. Artificial inoculation with the conidia induced typical symptom on leaves, which was not distinguishable from those of ascospore infection, which has been considered as a primary inoculum source in nature. Also the morphology of the conidia produced on PDA was not different from those formed on artificially inoculated leaves or on naturally infected leaves at later stage of symptom development. Accordingly, we report the role of the conidia as a secondary inoculum of the circular leaf spot pathogen of persimmon for the first time.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.287-292
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• 1983

Incubation period of rice neck blast was investigated by injection of conidial suspension of Pyricularia oryzae into young panicles inside the flag leaf sheath at booting stage. Eleven to fifteen days were taken for symptom appearance from the date of injection. About two days were taken from conidia germination until infection occurred, the incubation period was determined as nine to thirteen days for the symptom development of neck blast in rice plants.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.421-427
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• 2015

Citrus scab disease is one of the destructive diseases that reduce the value of fruit for the fresh market. We analyzed the process of symptom development after infection with scab pathogen $Elsino{\ddot{e}}$ fawcettii in the susceptible satsuma mandarin leaves to observe the structural modification against pathogen. The cuticle and epidermal cells along with 3-5 layers of mesophyll tissue were degraded 1-2 days post inoculation. Surrounding peripheral cells of degraded tissues grew rapidly and then enveloped the necrotic area along with the growing conidia. Cross sections through the lesion revealed hyphal colonization in epidermis and mesophyll tissues. In response to the pathogen colonization, host cell walls were lignified, inner cells were rapidly compartmentalized and a semi-circular boundary was formed that separated the infected region from the non-infected region, and finally prevented the intercellular pathogen spread.

• Asian Journal of Turfgrass Science
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• v.6 no.2
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• pp.99-111
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• 1992

Yellow patch as leaf blight caused by binucleate Rhizoctonia occured in bentgrass (Agrostis Palustris Huds), zoysiagrass (Zoysia japonica Steud) and Kentucky bluegrass (Poa pratensis L.) from several golf couses in Korea. Binucleate Rhizoctonia was isolated from the infected lesions and was identified Rhizoctonia cerealis. Rhizoctonia cerealis infected crown, stem and leaf tissue, and the symptom was light yellow circular patch upto 1 m in diameter on bentgrass golf green. Individual infected leaf near the margin of patch developed first red and finally turn brown. As zoysiagrass lawn, the symptom was 30~40cm circular patch that occured zoysiagrass shooting time as spring, and there could not sheeted in severe lesion. In case of sheeted, zoysiagrass was first irregular leaf sopt and finally dead. Hypha diameter of Rhizoctonia cerealis was $2.5~6.3\mu\textrm{m}$(average $3.8\mu\textrm{m}$) and colar was white to buff. Monilioid cell size was $5.8~12.5$\times$13.8~37.5\mu\textrm{m}$. Sclerotia size was 0.2~2.0mm and color was white to brown. Optium temperature for the hypha growth was $23^{\circ}C$. There was a little difference in pathogenicity among the isolates.