• Journal of the Korean Society of Tobacco Science
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• v.7 no.2
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• pp.129-139
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• 1985

cent was carried out to study on the effect of temperature and humidity to chemical tobacco leaves during the yellowing stage. The results were follows : In the condition of high humidity and low temperature, yellowing time was delayed ; leaf color appeared lack clearness. In the higher temperature and the lower humidity during the yellowing stage : total sugar, reducing sugar and malic acid content were increased. Decomposition of nitrogenous components elevated in $38^{\circ}C$, 85%RH. Changes of total nitrogen content correlated with total curing time. Adecrease of linolenic acid with a corresponding increase of chlorogenic acid proceeded in the condition of low temperature and high humidity. In a view of tobacco quality by chemical components, the low temperature and high humidity during the yellowing stage decreased quality of tobacco leaves. It is considered to control of the proper condition of temperature and humidity during the yellowing.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.293-297
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• 2015

This study was conducted to evaluate the influence of feeding leaf positions on the growth, net formation of fruits, and occurrence of leaf yellowing symptoms (LYS) in muskmelon plants. Plants having five or ten more leaves above the fruit-bearing node produced the greater biomass than those of plants having equal or five less leaves above the fruit-bearing node. The number of leaves above the fruit-bearing node also influenced on the occurrence of LYS. The number of plants with LYS decreased as the number of leaves borne on the nodes above the fruit-bearing node increased. The LYS infected ratio of BL-5 treatment were the greatest, while fruit weight of BL+5 treatment were the greatest among all the tested treatments. In addition, the net formation of BL-5 treatment showed the poorest. Results indicated that maintaining the higher number of leaves over the fruit-bearing node might be feasible the practical method for coping physiological damages from yellowing symptoms.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.10-16
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• 1999

Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.

• 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 Plant Pathology
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• v.11 no.3
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• pp.197-209
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• 1995

This paper is a third report about the new fungal diseases of economic resource plants in Korea. It contains short descriptions on symptoms, occurrence conditions, pathogen, and some phytopathological notes for each of 10 fungal plant diseases. They are angular leaf spot of Achyranthes japonica by Cercospora achyranthis causing leaf spot and defoliation in the shade of plants, leaf spot of Armoracia lapathifolia by Cercospora armoraciae causing leaf spot to blight from the rainy season to autumn, hypophyllous mold of Dioscorea tokoro by Distocercospora pachyderma causing leaf spot and yellowing, hypophyllous mold of Artemisia spp.by Mycovellosiella ferruginea causing leaf spot and yellowing, angular leaf spot of Aralia elata by Pseudocercospora araliae causing velvety leaf spot and defoliation, hypophyllous mold of Lycium chinense by Pseudocercospora chengtuensis causing velvety leaf spot and defoliation from the rainy season to autumn, angular leaf spot of Diospyros lotus by Pseudocercospora disospyri-morrisianae causing leaf spot and defoliation from summer to autumn, brown leaf spot of Impatiens textori by Pseudocercospora nojimae causing leaf spot to blight from the rainy season, leaf spot of Cephalonoplos segetum by Ramularia cirsii causing leaf spot to blight throughout the growing season, and white mold of Leonurus sibiricus by Ramularia leonuri causing leaf spot to blight mostly in autumn.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.2
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• pp.9-15
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• 1983

The effect of leaf dehydration process and air flow capacity of bulk curing on physical properties and composition of cured leaves was studied, respectively, during flue- curing. Cured leaves from excessive moisture during yellowing stage and those from rapid dehydration Process inevitably during later stages, tend towards lower equilibrium moisture contents, higher shatter index, hither protein nitrogen, and leaf scalding or deterioration of Beaves with redish cast. Early dehydration at the yellowing stage re suited in increasing of p Bamitic, stearic, linoleic, and linolenic acid contents, but showed reduction of brightness difference between upper and lower surface of the cured leaves, Leaf surface lipid decreased with the progress of curing stages, more conspicuously during later stage. Lowering air flow capacity of fan by 50oye during stem drying stage resulted in increasing of leaf surface lipid and 25oye decreasing of electric power consumption , but curing period and kerosene consumption were not affected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.459-480
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• 1991

Physilogical disorders of P. ginseng occurred in farmer's field were reviewed in relation to symptom. In root, red skin, rough skin, rust, root rot complex, round root, fine root stripe, freezing injury, cracking, sleeping and uneven emergence were frequently appeared. In leaf and stem, yellowing, early defoliation, leaf bum, Papery leaf, white freezing injury, wind injury, stem cracking were the main troubles. Red skin of root and leaf yellowing gave the greatest negative impact on ginseng production. Some cases of damage by pesticides, excess boron and industrial pollutants were reported. Physiological disorders related to quality factors, such as inside cavity, inside white sponge-like ect. after processing were discussed.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.49-54
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• 2023

For unknown reasons, a few trees in a private chestnut orchard in Icheon si, Gyunggi-do suffered leaf chlorosis and growth decline. Based on symptoms, phytoplasma was a probable cause. Leaf samples were collected from two symptomatic and non-symptomatic trees in the orchard for phytoplasma detection. An amplicon of about 1.2 bp size was obtained from both symptomatic trees by PCR with the universal 16S rDNA primers. Sequences of these amplicons were found to have 99% nucleotide sequence identity to the corresponding genomic region of 16SrIII (X-disease group). More than 100 phytoplasma isolates, such as Candidatus phytoplasma pruni, Milkweed yellows phytoplasma, Goldenrod yellows phytoplasma, Tsuwabuki witches'-broom phytoplasma, Candidatus Phytoplasma trifolii, etc. were involved in the list. Phylogenetic analysis revealed that the sequence obtained in this study closely clustered with Candidatus phytoplasma groups. While one of the amplicons shared 91% identity with the Candidatus phytoplasma castaneae, the other shared only 47%. It needs further analysis and investigation to determine the exact taxonomy. Meanwhile, based on the analysis of the sequences, chlorosis, and small leaves were associated with phytoplasma.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.151-154
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• 2007

Phytoplasma was identified from leaf lettuce (Lactuca sativa) cultivated in commercial green-house in Korea. Diseased leaf lettuce revealed proliferation of shoots, and yellowing and shrinking of leaves (lettuce proliferation-K). Polymerase chain reaction (PCR) with universal primer pair P1/P6, and aster yellows (AY) specific primer pair R16F1/R1 amplified 1.5kb and 1.1kb length of DNA fragments, respectively. Nucleotide sequences of 16S rRNA gene were determined (Gen Bank accession no EF489024). Phylogenetic analysis of 16S rDNA showed the closest relationship with AY phytoplasma (GenBank accession no. AY389822 and AY389826), indicating that lettuce proliferation-K is a member of AY. Phytoplasma bodies were detected in phloem sieve tubes of diseased lettuce by transmission electron microscopy. The structures had round or pleomorphic shapes with a diameter of 130-300nm. Phylogenetic analysis of 16S rRNA gene, microscopic observation of phytoplasma bodies and symptomatology indicated that lettuce proliferation-K is caused by phytoplasma in the AY group. This is the first report of phytoplasma disease in lettuce in Korea.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.57-63
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• 1997

The composition of leaf surface lipid in Flue-cured tobacco and their changes during curing was investigated. The flue-cured variety, Nicotiana tabacum cv. NC 82 was cultivated at Eumsung experiment station in 1996. The samples of riced leaves with different stalk Position(Lugs, Cutter, Leaf and Tips) and different curing stage at half yellowing(24hr), yellowing(48 hr) , color axing(72 hr), midrib drying(96 hr) and cured(120 hr) were collected for analysis of leaf surface lipid. $\alpha$ - and $\beta$ - 4, 8, 13-Duvatriene-1, 3-diol($\alpha$, $\beta$-DVT) were major components in leaf surface lipid extracted with methylene chloride and sugar ester was detected slightly DVT content was increased with ascending stalk position, but increasing trend of total hydrocarbon was not observed. While DVT was decreased throughout curing of tobacco leaves, hydrocarbon content did not show significant change during curing process. Twenty-two duvane compounds were detected by capillary GC in duvane fraction isolated from leaf surface lipid and of which 11 compounds were identified by GC-MS. These compounds were decreased with curing in all stalk position.