• Horticultural Science & Technology
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• v.33 no.1
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• pp.114-123
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• 2015

Plants can respond and adapt to cold stress through regulation of gene expression in various biochemical and physiological processes. Cold stress triggers decreased rates of metabolism, modification of cell walls, and loss of membrane function. Hence, this study was conducted to construct coexpression networks for time-based expression pattern analysis of genes related to cold stress in Chinese cabbage (Brassica rapa ssp. pekinensis). B. rapa cold stress networks were constructed with 2,030 nodes, 20,235 edges, and 34 connected components. The analysis suggests that similar genes responding to cold stress may also regulate development of Chinese cabbage. Using this network model, it is surmised that cold tolerance is strongly related to activation of chitinase antifreeze proteins by WRKY transcription factors and salicylic acid signaling, and to regulation of stomatal movement and starch metabolic processes for systemic acquired resistance in Chinese cabbage. Moreover, within 48 h, cold stress triggered transition from vegetative to reproductive phase and meristematic phase transition. In this study, we demonstrated that this network model could be used to precisely predict the functions of cold resistance genes in Chinese cabbage.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.67-75
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• 1996

Capsicum annuum 'Nokkwang' plug seedlings were treated with 9 different day and night temperatures to investigate on growth and differentiation in controlled environment conditions. The plant height was the most affected by day temperature and DIF and stem length was the similler results as plant height. However, Leaf unfolding rate and leaf length and width increased as average daily temperature increased. and especially fresh weight was worst at ADT was $15^{\circ}C$ and increased as ADT increased. In contrast with fresh weight, chlorophyll content calculated highest when ADT was $15^{\circ}C$, and decreased as NT increased respectively. The stem lengths were not significantly different among treatments with exception of DT/NT=15/$15^{\circ}C$ which significantly decreased. The ultimate +DIF condition, DT/NT=30/$15^{\circ}C$, caused high T/R ratio due to abundant top growth. It is concluded that DT is $22.5^{\circ}C$, and NT is ranged from $15^{\circ}C$ to $22.5^{\circ}C$ to be produced short, healthy plug seedlings in Capsicum annuum 'Nokkwang'.

• Journal of Ginseng Research
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• v.26 no.2
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• pp.85-88
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• 2002

This study was carried out to obtain information of the photosynthetic rate at various temperature and light intensity, stomata, chlorophyll, specific leaf weight, characteristics of aerial part and root in ginseng new cultivars developed by pure line selection. The light saturation point of leaves in new cultivars and Jakyungjong were 15,000 lux, and the optimum air temperature on the photosynthesis of new cultivars and Jakyungjong were 20$\^{C}$. The photosynthetic rates were increased in order of Jakyungjong, Gopoong, Chunpoong and Yunpoong. The dark respiration rate of leaves in ginseng cultivars were increased according to the increasing of temperature, and the dark respiration rate of leaves of Yunpoong was the highest among cultivars. The specific leaf weight (SLW) were increased in order of Jakyungjong, Yunpoong, Gopoong, Chunpoong, but total chlorophyll contents were not different among cultivars. Stomata frequency of Yunpoong was the highest being 69.2ea among cultivars, while the length of stomata was reverse. Yunpoong was superior in aerial part among ginseng cultivars : the number of stem was 1.8ea, the number of palmately leaves was 7.7ea, the number of leaflets was 41.0ea, leaf area was 12.3 dm$^2$ The root weight were increased in order of Jakyungjong, Gopoong, Chunpoong and Yunpoong. Chunpoong and Gopoong hove good root shape the length of tap root in Chunpoong and Gopoong were the longest being 6.5 cm and 6.8 cm respectively, but that in Yunpoong was the shortest being 4.4 cm.

• Smart Media Journal
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• v.9 no.4
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• pp.176-186
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• 2020

The size and shape of crops are diverse, and the growing environment is also different. Therefore, when one uses a drone to spray pesticides, the characteristics of each crop must be considered, and flight conditions such as the flight height and forwarding velocity of the drone should be changed. The droplet flow of pesticides is affected by various flight conditions, and a large change occurs in the sprayed area. As a result, an uneven distribution of liquid may be formed at the wake, and the transport efficiency will be decreased as well as there would be a risk of toxic scatter. Therefore, this paper analyzes the degree of distribution of pesticides to the crops through numerical analysis when pesticide is sprayed onto the selected three crops with different characteristics by using agricultural drones with different flight conditions. On the purpose of establishing a guideline for spraying pesticides using a drone in accordance with the characteristics of crops, this paper compares the amount of pesticides distributed in the crops at the wake of nozzle flow using the figure of merit, and the sum of transported liquid rate divided by the root mean square of the probability density function.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.144-150
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• 2002

Indian mallow is characterized by the rapid growth and high harvest of the fibrous materials. This study was carried out to investigate the sheet properties of Hanji using Indian mallow, made by different pulping methods, such as alkali and sulfomethylated pulpings and different stock compositions, various mixing ratios of bast fiber, woody core and whole stalk fibers. The results from this study were summarized as follows. The length and width of the bast fibers were 1.40-430 mm(av. 235 mm), and 9.2-26.4 ㎛(av.18.3 ㎛), respectively. The cell wall thickness was 4.0-115 ㎛(av. 7.7 ㎛). Runkel ratio, flexibility coefficient and fiber length/fiber width ratio were 1.38, 0.42 and 128 respectively. Bast fiber and whole stalk were cooked by alkali and sulfomethylated methods. Sulfomethylated pulping resulted in superior pulp in terms of yield and quality as compared with those of alkali pulping. The pulp yields of bast fiber was higher than those of whole stalk

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.63-68
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• 1985

This study was conducted to investigate the dry matter production and distribution ratio of dry matter produced for each of 5 botanical types (Virginia-Small Seed, Virginia-Large Seed, Spanish, Valencia, Shinpung) of Peanut (Arachis hypogaea L.) in Peanut culture limiting region. The total dry weight increased in order of Virginia-Large seed, Virginia- Small Seed, Shinpung, Spanish, Valencia type. The maximum Crop growth rates (Cmax) were Virginia-Small seed 18.22-23.41 g/㎡/day, Virginia-Large seed 19.61-20.03 g/㎡/day, Shinpung 16.33-19.77 g/㎡/day, Spanish 13.86-16.28 g/㎡/day, Valencia 13.97-16.25g/㎡/day, respectively. LAI showed the high value at vinyl-mulching than non-mulching. In the early filling stage, distribution ratio of dry matter produced showed the highest at the shinpung type than the other types.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.81-87
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• 2019

The investigation of mycelial growth for artificial cultivation in T. albuminosus determined that within PDA, YM, MEA medium, both KNCAF 9001 and 9002 strains showed the highest mycelial growth in MEA media with 89, 81 mm, respectively, followed by YM, PDA in respected order. Furthermore, optimal mycelial growth of 89 and 77 mm in 9001 and 9002, respectively, at 25 ℃. Mycelial growth rapidly decreased at 30 ℃, but it was confirmed that it survived at 40 ℃. At pH 6, mycelial growth was fast with growth of 89 and 88 mm for both 9001 and 9002, respectively. In the case of 9001, the addition of with cotton seed hull(80%) and rice bran (20%) each other resulted in maximum productivity of 99 mm/10 days. The result differed in order of corn cob(97 mm), oak sawdust(96 mm) and poplar sawdust(93 mm). Ultimately, the result confirmed that addition of rice bran in comparison to bran resulted in higher yield. Even with identical medium component, 9002 showed the same tendency as 9001 but its growth was relatively slower than 9001. The effect of mycelial growth on the moisture content of the medium was best at 101. 94 mm/10 days when the moisture content of 9001 and 9002 was 65%. Mycelial growth rate tended to be slower when the moisture content was higher or lower than 65%.

• Journal of Mushroom
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• v.21 no.4
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• pp.241-246
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• 2023

Flammulina velutipesis a popular edible mushroom in South Korea, accounting for approximately 30% of the total mushroom export in the country. Despite its significant position in the domestic mushroom industry, approximately 65% of the cultivated F. velutipes are foreign varieties. To secure variety rights and enhance competitiveness in the export market, there is a need to develop domestic varieties with stable production and excellent shelf life. We focused on breeding a new variety called 'Baekwoon' through mon-mon crossing, using 'Baekseung' and an international collection strain (KMCC02260) as parents. Baekwoon exhibited faster mycelial growth rates at 15 ℃ and 25 ℃ and higher mycelial growth across four tested media compared to that of the control variety. Under bottle cultivation, Baekwoon had a mycelial cultivation period that was shorter by approximately 2 days compared to that of the control. The yield of Baekwoon was 228.0±10.9 g, 8.3% more than that of the control. Furthermore, Baekwoon displayed distinct morphological features characterized by a larger pileus and thicker stipe compared to that of the control variety. Genetic tests confirmed that Baekwoon is genetically different from both parental strains and the control variety. It is expected that the newly developed F. velutipes variety, Baekwoon, will be evaluated for its adaptation in different regions and actively promoted in the field, ultimately increasing the market share of domestic varieties.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.131-142
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• 2024

The purpose of this study was to estimate the optimal stand density criteria for each growth stage of Chamaecyparis obtusa (Siebold & Zucc.) Endl. to achieve the timber production goal for cypress forests and develop an optimal silvicultural system for forest thinning. A relative yield index (Ry) value of 0.75, presented as a stand density management criterion index, was estimated by analyzing the relationship characteristics between the composition ratio and stand density of slender trees from 216 sample plots of the recruited cypress forests. The analysis of the feasibility of achieving each production target in the existing silvicultural system for C. obtusa revealed that the growth rate according to the parameters of forest land productivity, such as site index and thinning intensity according to the increase in age, was not properly reflected. In the thinning system for each timber production target analyzed in this study, 353 high-quality large hardwoods from 498.1 m³/ha, 703 high-quality medium hardwoods from 376.2 m³/ha, and 1,758 small-diameter hardwoods from 249.5 m³/ha could be harvested. Although the silvicultural system prepared on the basis of the results of this study cannot be uniformly applied according to various management goals, this study is meaningful in that it presents empirical reference standards based on the stand density management diagram that reflects the growth characteristics of cypress forests in South Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.53-68
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• 1969

The nutriophysiological response of rice plant to root environment was investigated with eye observation of root development and rhizosphere in situation. The results may be summarized as follows: 1) The quick decomposition of organic matter, added in low yield soil, caused that the origainal organic matter content was reached very quickly, in spite of it low value. In high yield soil the reverse was seen. 2) In low yield soil root development, root activity and T/R value were very low, whereas addition of organic matter lowered them still wore. This might be contributed to gas bubbles around the root by the decomposition of organic matter. 3) Varietal difference in the response to root environment was clear. Suwon 82 was more susceptible to growth-inhibitine conditions on low-yield soil than Norin 25. 4) Potassium uptake was mostly hindered by organic matter, while some factors in soil hindered mostly posphorus uptake. When the organic matter was added to such soil, the effect of them resulted in multiple interaction. 5) The root activity showed a correlation coeffieient of 0.839, 0.834 and 0.948 at 1% level with the number of root, yield of aerial part and root yield, respectively. At 5% level the root-activity showed correlation-coefficient of 0.751, 0.670 and 0.769 with the uptake of the aerial part of respectively. N, P and K and a correlation-coefficient of 0.729, 0.742 and 0.815 with the uptake of the root of respectively N.P. and K. So especially for K-uptake a high correlation with the root-activity was found. 6) The nitrogen content of the roots in low-yield soil was higher than in high-yield soil, while the content in the upper part showed the reverse. It may suggest ammonium toxicity in the root. In low-yield soil Potassium and Phosphorus content was low in both the root and aerial part, and in the latter particularly in the culm and leaf sheath. 7) The content of reducing sugar, non-recuding sugar, starh and eugar, total carbohydrates in the aerial part of plants in low yield soil was higher than in high yield soil. The content of them, especially of reducing sugar in the roots was lower. It may be caused by abnormal metabolic consumption of sugar in the root. 8) Sulfur content was very high in the aerial part, especially in leaf blade of plants on low yield soil and $P_2O_5/S$ value of the leaf blade was one fifth of that in high yield soil. It suggests a possible toxic effect of sulfate ion on photophosphorization. 9) The high value of $Fe/P_2O_5$ of the aerial part of plants in low yield soil suggests the possible formation of solid $Fe/PO_4$ as a mechanical hindrance for the translocation of nutrients. 10) Translocation of nutrients in the plant was very poor and most nutrients were accumulated in the root in low yield soil. That might contributed to the lack of energy sources and mechanical hindrance. 11) The amount of roots in high yield soil, was greater than that in low yield soil. The in high-yield soil was deep, distribution of the roots whereas in the low-yield soil the root-distribution was mainly in the top-layer. Without application of Nitrogen fertilizer the roots were mainly distributed in the upper 7cm. of topsoil. With 120 kg N/ha. root were more concentrated in the layer between 7cm. and 14cm. depth. The amount of roots increased with the amount of fertilizer applied.