• The Plant Pathology Journal
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• v.17 no.4
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• pp.194-200
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• 2001

Chrysanthemum stunt viroid (CSVd) ws identified in chrysanthemum cv. Chunkwang showing symptoms of stunt with leaf distortion (K1) and stunt with chlorosis of leaves (K2) collected from the main cultivation area of Masan, Kyongnam province in Korea. The specific RNAs related with the diseased chrysanthemums were detected. Full-length 354 bp CSVd cDNAs were amplified from infected tissue by reverse transcription and polymerase chain reaction using a pair of primers specific for CSVd sequence. The amplified cDNA products were analyzed by agarose gel electrophoresis and the specific cDNAs were cloned. Nucleotide sequences of the two CSVd isolates K1 and K2 varied. Phylogenetic analysis of the nucleotide sequences of CSVd isolates indicated that K1 was closely related with J2 and Am 2 isolates. K1 and K2 were transmitted by grafting to Dendranthema grandiflorum cv. Mistletoe, Gynura aurantiaca, and Lycopersicon esculentum cv. Rutgers. This is the first report of CSVd in D. grandiflorum in Korea.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.132-137
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• 1997

Phytotoxicity of the culture filtrate and culture conditions for the production of the phytotoxin by Exserohilum monoceras 92-044 were examined. The necrotic lesions were developed on the leaves of Echinochloa crus-galli within 48 hrs after inoculation of the culture filtrate, and the leaves were completely blighted within 5∼7 days. Maximum toxicity was found in the culture broth containing 20% V-8 juice. Phytotoxin accumulation and fungal growth reached their highest peak at around 11 days. Typical symptom appeared on the leaf of E. crus-galli within 48 hrs. Only a weak chlorosis appeared on rice, Arundinella hirta (THUNB) and henry crabgrass (Digitaria sanguinalis SCOP.), but no further symptom developed.

• Korean Journal of Microbiology
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• v.13 no.1
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• pp.31-36
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• 1975

Chlorella ellipsoidea cells were cultured in a phosphate, magnesium, sulfur or potassium-free medium. Some portions of cells were taken out at intervals during the culture, and physiological activities such as growth rate, reproduction, photosynthetic activity, and biosynthesis of cholorophyll of macro-element deficient cells were measured. 1) Generally, growth rate, reproduction, photosynthetic activities, and biosynthesis of chlorophyll of the macro-element deficient cells decreased more or less, compared with those of the normal cells. 2) The growth and reproduction of the algal cells in sulfur, or magnesium free medium were retarted severely with the chlorosis ; the photosynthetic activity and the content of chlorophyll showed the same tendency. 3) It is considered that the decrease in growth rate of macro-element deficient Chlorella cells is due to the decrease in photosynthetic activity owing to the decrease in chlorophyll content of the cells.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.377-382
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• 2005

Infection rate of Chrysanthemum stunt viroid (CSVd) in 64 commercial chrysanthemum cultivars cultivated in Korea ranged from 9.7 to 66.8$\%$. Symptoms on leaves of CSVd-infected chrysanthemum included yellow spots, chlorosis, vein clearing, vein bending and crumpling. CSVd induced flower malformation in 'Scot', color change in 'Sharotte', and color breaking in 'Sharon'. CSVd caused reduction of plant height, leaf size, flower size and the flowers number by $32-50\%,\;26-35\%$, $14-36\%\;and\;14-75\%$, respectively. In conclusion, CSVd affected plant height, leaf size and flower quality in chrysanthemum plants.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.297-302
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• 2020

Root-knot nematodes (Meloidogyne spp.) are the most destructive group of plant-parasitic nematodes. Plants infected by Meloidogyne spp. develop above-ground symptoms, stunting, yellowing, nutrient deficiencies, and gall formations with typical hook-shaped root tips. Infected plants experience yield losses. During 2018-2019 survey, leaf chlorosis rice plants were found in 206 fields of 67 counties in Guangxi, China, around 30 days after transplanting. Galls and hooked tips on the roots and pear-shaped females were observed. About 32.04% of fields were infested with the nematode. The nematodes were identified as Meloidogyne graminicola base on morphological and molecular analysis. To the best of our knowledge, this is the first report of M. graminicola on rice plants in Guangxi, China. The results of this study urge the discovery of resistant cultivars and the development of management strategies.

• Korean Journal Plant Pathology
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• v.14 no.2
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• pp.188-190
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• 1998

Fusarium wilt of lisianthus occurred severely throughout all cultivation areas, especially in alpoine areas during summer season and the disease incidence was 5 to 30 percent in Korea. The major symptoms of the disease were wilt with chlorosis and water deficiency, stunted plants and scorched leaves. Severe symptoms appeared just after high temperature period around late August in Daekwallyong area. Whit and pale red colored mycelia were developed on stems of infected plants near the soil surface. The causal organism of Fusarium wilt of lisianthus was isolated and identified as Fusarium oxysporum f. sp. eustomae on the basis of pathogenic and cultural characteristics. The causal organism was reisolated from all infected and inoculated stems of plants. This is the first report referring to F. oxysporum f. sp. eustomae of lisianthus in Korea.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.399-403
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• 2021

Stem blight symptoms were observed in greenhouse-grown bottle gourds (Lagenaria siceraria) in Wanju, Korea. Infected plants showed leaf chlorosis and wilting; the plants eventually died with the infected leaves remaining attached, and black sclerotia formed on the diseased stem. Based on the morphological characteristics and pathogenicity results and sequence analyses of the internal transcribed spacer, translation elongation factor 1-α, β-tubulin, and calmodulin regions, the isolated fungus was Macrophomina phaseolina. This is the first report of charcoal rot in Lagenaria siceraria caused by Macrophomina phaseolina in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.148.1-148
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• 2003

Natural virus infection of cultivated Daphe odora plants showing chlorosis and stunting was observed and their causal agent was investigated. An isolate of isometic virus was purified from infected leaf tissues, and it could infect systemic severe mosaic on Chenopodium quinoa and C. amaranticolor. cDNA library was generated from partially purified viral RNAs and oligo dT primer-pSPORTl system, and recombinant clones were selected and their inserts were sequenced randomly. Nucleotide sequences of the virus were analyzed by BLAST, and it was closely related to members of subgroup B in the genus Nepovirus. The sequence analysis suggest that the virus was identified as an isolate of Cycas necrotic stunt virus (CNSV) because it was 89.7 ％ and 94.7 ％ identical to known CNSV for the CP and 3' noncoding region, respecitively. RT-PCR was performed to screen disease incidence of CNSV in Daphe plants, and five out of 10 plants (50 ％) were infected by CNSV This is the first sequence information of CNSV from Daphe plants.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.297-305
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• 2014

In order to understand the contribution of seaweed aquaculture to nutrients and carbon cycles in coastal environments, we measured the nutrients & carbon uptake rates of Porphyra yezoensis Ueda sampled at Nakdong-River Estuary using a chamber incubation method from November 2011 to April 2012. It was observed that the production rate of dissolved oxygen by P. yezoensis (n=30~40) was about $68.8{\pm}46.0{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and uptake rate of nitrate, phosphate and dissolved inorganic carbon (DIC) was found to be $2.5{\pm}1.8{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, $0.18{\pm}0.11{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and $87.1{\pm}57.3{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, respectively. There was a positive linear correlation existed between the production rate of dissolved oxygen and the consumption rates of nitrate, phosphate and DIC, respectively, suggesting that these factors may serve as good indicators of P. yezoensis photosynthesis. Further, there was a negative logarithmic relationship between fresh weight of thallus and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (0.1~0.3 g) were much more efficient at nutrients and $CO_2$ uptake than old specimens. It means that the early culturing stage than harvesting season might have more possibilities to be developed chlorosis by high rates of nitrogen uptake. However, N & C demanding rates of Busan and Jeollabuk-do, calculated by monthly mass production and culturing area, were much higher than those of Jeollanam-do, the highest harvesting area in Korea. Chlorosis events at Jeollabuk-do recently might have developed by the reason that heavily culture in narrow area and insufficient nutrients in maximum yield season (Dec.~Jan.) due mostly to shortage of land discharge and weak water circulation. The annual DIC uptake by P. yezoensis in Nakdong-River Estuary was estimated about $5.6{\times}10^3\;CO_2$ ton, which was about 0.03% of annual carbon dioxide emission of Busan City. Taken together, we suggest more research would be helpful to gain deep insight to evaluate the roles of seaweed aquaculture to the coastal nutrients cycles and global carbon cycle.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.105-114
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• 2004

This pot experiment was. conducted to investigate the effects of systematic variation application of Fe, Mn, Cu, and Zn on forage performance of orchardgrass and white clover. The treatments of systematic variation were 0/100, 25/75, 50/50, 75/25, and 100/0％ in the Fe/Cu(trial-1), Mn/Zn(trial-2), and Fe + Cu/Mn + Zn(trial-3), respectively. The treatments of Fe/Mn/Cu/Zn(trial-4) were composed of 70％ in main element and 10％ in other 3 elements, respectively. 1. In general, the unbalanced applications of Fe and Mn resulted in the Mn and Fe deficiencies(chlorosis) on white clover, respectively, because of the antagonism between Fe and Mn. In white clover, the traits of growth, root/nodule, and flowering, which were influenced by the systematic variation of Fe, Mn, Cu, and Zn, were closely correlated to each other. In the Fe/Cu trial, the 0/100 and 25/75 induced a Fe-deficiency on white clover, and the 0/100 also showed poor root growth and flowering. In addition, the 50/50 and 75/25 showed an early flowering of white clover. 2. In the Mn/Zn trial, the 0/100 induced a severe Mn-deficiency(chlorosis) on white clover. The 25/75 and 50/50, however, diminished the chlorosis symptom. The 75/25 and 100/0 showed generally good root growth and flowering of white clover. 3. In the Fe + Cu/Mn + Zn trial, the 0/100 induced a Fe-deficiency, and the 100/0 induced a Mn-deficiency on white clover, which were correlated to the poor root growth and flowering. The 75/25 showed good root growth and flowering of white clover. 1be flowering of white clover tended to be more influenced by the Fe + Cu than by the Mn + Cu ratios. 4. In the Fe/Mn/Cu/Zn trial, the Fe and Mn deficiencies on white clover, which were influenced by the Mn and Fe treatments, also occurred. The Cu and Zn-deficiency symptoms, however, were not recognized. General differences have been showed in the numbers of flowers as following orders; Zn > Cu > Mn > Fe - 70% treatments.