• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.99-108
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• 1995

The experiment was carried out to define the effect of the boron in nutrient solution on the development of mulberry root and cold damage. The length of shoots only attained about 50cm and then stopped in case of boron deficiency, while the mulberry trees developed vigorous and attained over 190cm long under boron supply condition. When boron is deficient, the measles appeared on surface of the stem and the necrosis appeared on the petiole, midribs and veins of leaves. At 70 days after planting, almost all new roots and old roots changed to brown, the lateral roots became necrosis by boron deficiency. After three days of stopping boron supply, many new roots changed to brown and after two days of boron resupply, new roots began to grow out and then new roots normally developed. Content of boron in leaves and barks increased by the increase of boron concentration in nutrient solution and maximum boron content in leaves and barks was obtained with boron-sufficient treatment of 0.5ppm. Treatment of 0.5ppm boron supply indicated that the leaves and barks contained more phospholipid, protein, sugar, RNA and proline than treatment of 0.01ppm boron supply in nutrient solution. The cuttings grown in boron supply nutrition have a sufficient tolerance at -10$^{\circ}C$ and -15$^{\circ}C$ for 24 hours while cuttings grown in boron-deficient nutrition have a weak tolerance at the same condition. As mentioned above, we can conclude that the effect of boron deficiency on root development is much severe and the relationship between the lack of boron and cold damage is very closely related.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.182-186
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• 1988

This study was conducted to level up the tolerance of tobacco plant against bialaphos herbicide through tissue culture. The relatively good shoot regeneration from the subcultured calli treated with bialaphos at 0.5 ppm was observed in old the tobacco varieties tested such as NC 82, BY 4 and KA 101. However, at the treatment of bialaphos 1.0 ppm, shoot regeneration was only made in KA 101 variety, showing better regeneration than that of untreated one, When these shoots were transfered to the medium containing of bialaphos 10.0 ppm, the percentage of living shoots (i.e. tolerant plant) was very low, showing 2.43% in NC 82, 2.76% in KA 101 and 0.78% BY 4. Calli were induced and multiplied from leaf petiole of the above tolerant plants even under 2.5ppm of bialaphos, showing an average of 9% in NC 82 and 16% in KA 101 as compared with the untreated control. No calli were induced from tolerant plants as bialaphos concentration increased up to 5.0 ppm. Direct shooting from leaves of the above tolerant plants, that is selected at 10.0ppm of bialaphos treatment, was observed even under 10.0ppm of bialaphos treatment both in NC 82 and in KA 101 varieties, indicating that tolerance of tobacco plants against bialaphos can be greatly increased.

• Korean Journal of Medicinal Crop Science
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• v.6 no.2
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• pp.121-125
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• 1998

This experiment was carried out to investigate the effects of direct seeding and planting of seedlings in different ages on yield and yield characteristics of Cynanchum wilfordii $H_{EMSLY}$. Emergence date was three days earlier in direct seeding compared to May 14 in plots planted with one - or three - year - old seedlings. Petiole length was 16cm and 26cm longer in direct seeding and 1 - year - old seedlings, respectively, compared to 279cm in plot of 3 - year - old seedling. Root diameter was 0.4cm thicker in direct seeding and 0.5cm thicker in 1 - year - old seedlings compared to 1.0cm in seedlings of three years old. Root length was 7.2cm shorter in direct seeding, but was 0.6cm longer in 1 - year - old seedlings than 32.2cm in seedlings of three years old. Yield increased by 29 % in direct seeding and 55% in seedlings of one year old compared to 1,403kg/l0a in 3 - year - old seedlings. In cultivation of Cynanchum wilfordii $H_{EMSLY}$, the suitable planting methods were direct seeding or the use of 1 - year - old seedlings which were profitable at higher density as $50{\times}10cm$.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.218-228
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• 1999

This study was conducted to obtain the information on dry matter productivity in Angelica gigas Nakai for establishing the cultivation method. Cultivation methods such as direct seeding on Mar. 31, Apr. 15 and Apr. 30, and transplanting of $8^{\frac{1}{2}}$, 9, 12 months old seedling were investigated. There were similar tendencies in changes of agronomic characters for all cultivation methods. Dry weight started to increase from 120 DAS. Direct seedling showed vigorous growth for aerial part, whereas transplanting showed better underground part. The quadratic polynomial was suitable to dry weight of root after 120 DAS (or DAT) .Short growing time had higher RGR and NAR independent of cultivation method but Direct seeding on Mar. 31 and transplanting of 9 months old seedling had the highest CGRs. LAI was positively correlated with CGR, and CGR had the highest value as $6.74\g/m^2/day$ when LAI was 1.97. RGR and NAR increased as mean temperature was increased and showed the highest value around . The highest net production of leaf and petiole was obtained at 20 and$23^{\circ}C$, respectively.

• Korean Journal of Environmental Biology
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• v.19 no.4
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• pp.254-260
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• 2001

After investigating the developmental process of galls forming on leaf of Zelkova serrata and analyzing the composition and contents of the free amino acids in leaves, galls and haemolymph of aphids, we have come to the following results. Galls induced were mostly distributed on the middle of lower part of leaf to the petiole along vein and most of investigated leaves had one gall only. The growth of galls continued in length and width until Paracolopha morrisoni habitants which transformed into alate adult left the gall. These results also indicate that galls are closely connected with a portion of plant tissues as well as foods and habitats of aphids. 26${\sim}$29 kinds of free amino acids such as proline, alanine and valine and so on, detected in leaves, gall and haemolymph of aphids. The composition of free amino acids were similar in three materials examined, but proline and asparatic acid showed the highest quantity in the leaves and falls, respectively. In case of aphids, alanine was extremely higher as 18.4% of total contents of free amino acids, in 1st instar of fundatrix stage. Total contents of free amino acids in the apteral adult stage of aphid were also increased than in the 1st instar stage. This investigation implies that nitrogen source such as free amino acids is apparently a major growth-material like carbohydrates during development of galls in Zelkova serrata.

• Research in Plant Disease
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• v.21 no.4
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• pp.337-340
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• 2015

During July to November 2014, severe rust infection was consistently found on Peucedanum japonicum growing farm in Yeosu, Korea. The rust was observed mainly on lower leaf surfaces. Symptoms of typical plants included yellow-orange rust pustules were observed on the petiole and leaf surface with small yellowish to chlorotic lesions on the upper surface. No symptom was observed on flowers. Uredinia were occurred amphigenous on leaf surface, and occasionally caulicolous, scattered or loosely aggregate, rounded to oblong, 0.4 to 4 mm in diameter, covered by epidermis, then naked, surrounded by ruptured epidermis, pulverulent, and brown. Urediniospores were ovate-ellipsoid, ellipsoid or subglobose, light brown, 20 to $45{\times}15$ to $35{\mu}m$, walls 2 to $4{\mu}m$ thick. The resulting sequences were deposited in GenBank with accession No. KT778808, KT778809, and KT778810, respectively. Since this was the first accession of 28S sequence Puccinia jogashimensis, there was no exact match in GenBank nucleotide database. On the basis of the morphological characteristics and phylogenetic analyses of 28S rDNA, the fungus was identified as P. jogashimensis. To our knowledge, this is the first confirmed report on the occurrence of P. jogashimensis on P. japonicum in Korea.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.617-622
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• 2011

The study was conducted to determine the efficiency in producing spontaneous polyploids in some mandarin hybrids with different seed embryony. Seed formation by open pollination, frequency of spontaneous polyploids, and plant growth characteristics were evaluated in four mandarin hybrids with polyembryony such as 'Amakusa', 'Haruka', 'Hayaka', and 'Seminole' and two with monoembryony such as 'Benibae' and 'Harehime'. The mean number of the developed seeds per fruit was 10.0 and frequency of small seeds was 25.1%. Polyploids were selected from plants germinated in vitro by a flow cytometry and confirmed by chromosome analysis. One triploid was produced from 'Harehime', one tetraploid, 'Amakusa', and one tetrapoid, 'Benibae'. There were little differences in leaf shape, thickness, petiole length, and internode length between diploids and polyploids such as tri- or tetraploid. However, polyploids had larger stomata and lower density of stomata in abaxial epidermis than diploids. SPAS indicating chlorophyll content and photosynthetic rate were significantly affected by ploidy level. The results indicated that spontaneous polyploids might be produced by open pollination in some mandarin hybrids and monoembryony had higher frequency in polyploid occurrence than polyembryony.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.676-682
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• 2012

The objectives of this study focused on measuring chlorophyll fluorescence related to drought stress comparing some parameters. Almost parameters were declined although they were not significant on the basis of mean values of fluorescence of total leaf area. While the ratio of fluorescence intensity variable chlorophyll ($F_V$) to fluorescence intensity maximal chlorophyll ($F_M$) was not changed, the effective quantum yield of photochemical energy conversion in photosystemII (${\Phi}PSII$) and chlorophyll fluorescence decrease ratio ($R_{fd}$) were slightly reduced, indicating inhibition of the electron transport from quinone bind protein A ($Q_A$) to quinone bind protein B ($Q_B$). Some parameters such as non-photochemical quenching rate ($NPQ_{_-LSS}$) and coefficients of non-photochemical quenching of variable fluorescence (qN) in mid-zone of leaf and near petiole zone leaf were significantly enhanced within 4 days after drought stress, which can be used as physiological stress parameters. Decrease in ${\Phi}PSII$ could was significantly measured in all leaf zones. In conclusion, three parametric evidences for chlorophyll fluorescence responses such as ${\Phi}PSII$, NPQ, and qN insinuated the possibility of photophysiological indices under drought stress.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.336-339
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• 2003

Hydrocotyle maritima Honda used as medicinal plants for a hemostatic agent was investigated for in vitro regeneration. The petiole explants of H. maritima were cultured on callus induction medium containing growth regulators ($0{\sim}5\;mg/l$, NAA and $0{\sim}5\;mg/l$ 2,4-D) either in single or in combination with $0.1{\sim}2\;mg/l$ BA for 6 weeks. Although single treatments of 2,4-D or NAA resulted in callus formation, the best results were combination of $0.5\;mg/l$, 2,4-D and $0.5\;mg/l$, BA. $5\;mg/l$, NAA and $0.5\;mg/l$, BA, respectively. The highest number of shoot (12 shoots per callus) was achieved with $3\;mg/l$, Kinetin. Also, when pieces of embryogenic callus induced on the medium supplemented with $0.5\;mg/l$, 2,4-D and $0.5\;mg/l$, BA were subcultured on hormone-free medium, somatic embryos were differentiated and developed further into welldeveloped plants.

• Korean Journal of Medicinal Crop Science
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• v.20 no.4
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• pp.231-237
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• 2012

These studies were conducted to provide basic information on Korean ginseng cultivars and breeding lines (Panax ginseng C. A. Mey.) and to identify the variations that can be utilized in ginseng breeding programs. The agronomic characteristics was used to clarify the genetic relationships among Korean ginseng cultivars and breeding lines and to classify them into distinct genetic groups. Angle of petiole and number of fibrous root showed a wide variation from $15.0{\sim}67.8^{\circ}$ and 0~5, respectively. The average plant length was 54.2cm with a range of 37.9~64.8cm and the average stem diameter was 5.6mm with a range of 4.0~7.5mm. The average stem length was 31.9cm with a range of 21.8~37.9cm and the average root weight was 38.1 g with a range of 23.0~52.0 g. The 24 Korean ginseng cultivars and breeding lines were classified into 4 groups based on agronomic characteristics using the complete linkage cluster analysis. The I, II, III and IV groups included the 60.8%, 7.4%, 13.1% and 8.7% of the cultivars and breeding lines, respectively. The breeding lines in group I could be characterized as the group with the highest growth characters and yield components, such as plant length, stem diameter and root weight. The root weight, the yield component, had highly significant positive correlations with stem diameter, plant length and stem length.