• Korean Journal of Medicinal Crop Science
• /
• v.15 no.6
• /
• pp.429-433
• /
• 2007

Shoot weight of Orostachys japonicus should determine its profitability. The study was carried out to measure the effect of nitrogen (N) fertilization level (0, 5, 10, 20kg/10a) on its growth, morphological characters, and flowering. Night-break treatment of 2 hours at midnight were done since Aug. 25 when afterward samples were taken every 4 weeks to Nov. 16. Growth, morphological and flowering related characters were measured from each sample. Plant height, inflorescence length, number of leaves including bracts and stem diameter were decreased with increased N levels. Leaf and bract, floret, shoot and total dry weights as well as withering rate showed similar response to the above morphological characters. Florets were less formed with increased N levels but were not flowered due to the night-break treatment, meaning that N fertilization had little effect on its growth and anthesis of the florets.

• The Plant Pathology Journal
• /
• v.39 no.1
• /
• pp.108-122
• /
• 2023

Fusarium oxysporum f. sp. lycopersici (Fol) and Fusarium oxysporum f. sp. cubense (Foc), are the causal agent of Fusarium wilt disease of tomato and banana, respectively, and cause significant yield losses worldwide. A cost-effective measure, such as biological control agents, was used as an alternative method to control these pathogens. Therefore, in this study, six isolates of the Streptomyces-like colony were isolated from soils and their antagonistic activity against phytopathogenic fungi and plant growth-promoting (PGP) activity were assessed. The results showed that these isolates could inhibit the mycelial growth of Fol and Foc. Among them, isolate STRM304 showed the highest percentage of mycelial growth reduction and broad-spectrum antagonistic activity against all tested fungi. In the pot experiment study, the culture filtrate of isolates STRM103 and STRM104 significantly decreased disease severity and symptoms in Fol inoculated plants. Similarly, the culture filtrate of the STRM304 isolate significantly reduced the severity of the disease and symptoms of the disease in Foc inoculated plants. The PGP activity test presents PGP activities, such as indole acetic acid production, phosphate solubilization, starch hydrolysis, lignin hydrolysis, and cellulase activity. Interestingly, the application of the culture filtrate from all isolates increased the percentage of tomato seed germination and stimulated the growth of tomato plants and banana seedlings, increasing the elongation of the shoot and the root and shoot and root weight compared to the control treatment. Therefore, the isolate STRM103 and STRM104, and STRM304 could be used as biocontrol and PGP agents for tomato and banana, respectively, in sustainable agriculture.

• Korean Journal of Plant Tissue Culture
• /
• v.21 no.6
• /
• pp.347-351
• /
• 1994

To measure the time required for ginseng explants to become determined to form flower buds, we cultured zygotic embryos, seedlings, and cotyledonary nodes on MS medium supplemented with BA and GA$_3$of 5 ${\mu}$M each (flower inducing medium, FIM) for various periods and transferred to the basal medium. The explants required a minimum of 10 days on FIM to be determined. Histological observations revealed that the axillary meristem to be fated to develop into flower bud remained in a state of shoot meristem during the first 10 days of culture and differentiated into flower bud after 15 days of culture. We suggest that the in-vitro flowering system described in this study is useful in investigating (a) regulatory element(s) to cause the phase change from the vegetative to reproductive state by comparing predetermined explants with determined ones at the molecular level.

• Korean Journal of Soil Science and Fertilizer
• /
• v.25 no.1
• /
• pp.89-98
• /
• 1992

Glasshouse experiments were conducted to evaluate nodulation, and $N_2$ fixation of 73 strains of Bradyrhizobia isolated from nodules of groundnuts and/or cowpeas grown at various location in Korea and 31 strains of cowpea Bradyrhizobia obtained from overseas sources. Of the strains tested 51.9%, 26.4%, and 21.7% were rated fully effective, partially effective, and ineffective, respectively. Eight very effective strains were selected. Nodulation, shoot dry mass, whole plant dry mass, and plant total N content were significantly correlated with each other. The highly significant correlation of total N content and plant dry mass ($r=0.98^{**}$) indicates that plant dry mass can be used as a measure of strain effectiveness in preliminary test.

• The Korean Journal of Ecology
• /
• v.26 no.4
• /
• pp.165-172
• /
• 2003

The objectives of this study were to examine the physiological responses to ozone and to measure ozone uptake rates of Betula species exposed to relatively high concentration of pollutants. At the end of the growing season, photosynthesis, pigments contents, antioxidants (SOD and GR) and ozone uptake rates were measured or estimated at the leaves of five Betula species (Betula costata, B. davurica, B. platyphylla var. japonica, B. schmidtii and B. ermanii) exposed to 100ppb ozone concentration. On the termination of the experiment, growth effects were determined by measuring leaf area and dry weights of leaf, stem and root. Ozone treatment showed the significant reduction the leaf area and dry weight of four Betula species, except for B. ermanii. Shoot / root (SR) ratio of five species represented two different types. SR ratio of B. costata and B. davurica were lower than control, in contrast, SR ratio of B. platyphylla var. japonica, B. schimidtii and B. emani, were higher than that of control. The photosynthetic responses of five species were different in responses to ozone exposure. Four species, except for B. emanii, maintained or increased the stomatal conductance, but B. emanii decreased both stomatal conductance and photosynthesis. SOD activities of five species decreased by the ozone exposure, especially B. ermanii showed the largest reduction, GR activities of B. platyphylla var. japonica and B. schmidtii increased, B. costata and B. emanii decreased. Instantaneous ozone uptake rate was the highest at the leaves of B. ermanii and B. costata, ozone uptake per seedling was the highest at the leaf of B. schmidtii and B. emanii. It was concluded that B. costata, B. davurica and B. platyphylla var. japonica, appeared the growth reduction and visible ozone injury, were sensitive species to ozone, and B. schmidtii with the increased antioxidant activity and B. ermanii without the growth reduction were relatively resistant species to high ozone concentration at the early growing stage.

• Convergence Security Journal
• /
• v.20 no.1
• /
• pp.85-92
• /
• 2020

None of the recent cases of military secret leakages have leaked internal information using networks. This is because the Internet and the Intranet are physically separated, and has a difficult process when transmitting and receiving data through the Internet. Therefore, most of the leaked paths are to copy and hand over secrets, shoot and send them with a smartphone, or disclose after remembering them. So, the technology of blocking and detecting military secret leakages through the network is not effective. The purpose of this research is to propose a method to prevent information leakage by focusing on the insider behaviors, the subject of leakage, rather than the military secret. The first is a preventive measure to prevent the leakage behavior of military secrets, the second is to block suspicious access to the military secret data, and the last is to detect the leakage behavior by insiders.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.7
• /
• pp.686-696
• /
• 2011

To deal with pathogens, plants have evolved sophisticated mechanisms including constitutive and induced defense mechanisms. Phytohormones play important roles in plant growth and development, as well as in the systemic response induced by beneficial and pathogen microorganisms. In this work, we identified an Aspergillus ustus isolate that promotes growth and induces developmental changes in Solanum tuberosum and Arabidopsis thaliana. A. ustus inoculation on A. thaliana and S. tuberosum roots induced an increase in shoot and root growth, and lateral root and root hair numbers. Assays performed on Arabidopsis lines to measure reporter gene expression of auxin-induced/ repressed or cell cycle controlled genes (DR5 and CycB1, respectively) showed enhanced GUS activity, when compared with mock-inoculated seedlings. To determine the contribution of phytohormone signaling pathways in the effect elicited by A. ustus, we evaluated the response of a collection of hormone mutants of Arabidopsis defective in auxin, ethylene, cytokinin, or abscisic acid signaling to the inoculation with this fungus. All mutant lines inoculated with A. ustus showed increased biomass production, suggesting that these genes are not required to respond to this fungus. Moreover, we demonstrated that A. ustus synthesizes auxins and gibberellins in liquid cultures. In addition, A. ustus induced systemic resistance against the necrotrophic fungus Botrytis cinerea and the hemibiotrophic bacterium Pseudomonas syringae DC3000, probably through the induction of the expression of salicylic acid, jasmonic acid/ethylene, and camalexin defense-related genes in Arabidopsis.

• Horticultural Science & Technology
• /
• v.34 no.1
• /
• pp.77-83
• /
• 2016

The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.66 no.2
• /
• pp.171-181
• /
• 2021

The purposes of this study were to determine how changes in temperature affect germination rates and growth of hulled and dehulled barley, malting barley, and naked oat plants, and to measure chlorophyll content, photosynthetic efficiency, and secondary compounds (total phenol, total flavonoid, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) in plants grown at 13℃ or 25℃). Various types of barley seeds were collected from areas with ideal conditions for barley cultivation, hereinafter referred to as IA, and also from areas where barley cultivation is more difficult due to lower temperatures, hereinafter referred to as LTA. Seeds were tested for seed vigor. While there were significant differences in the electrical conductivity values between seeds collected from certain specific areas, no significant differences were evident between IA and LTA seeds, regardless of the type of barley seed. When plants were grown at 25℃, there were no significant differences in germination rates, plant height, root length and shoot fresh weight between plants originating from IA and LTA. However, there were differences in the measured parameters of some specific seeds. Similarly, under the low temperature condition of 13℃, no differences in the emergence rate, plant height, and shoot fresh weight were evident between plants originating from IA or LTA, regardless of the type of barley. However, there were differences between some specific seeds. One parameter that did vary significantly was the emergence date. Hulled barley and malting barley emerged 5 days after sowing, whereas naked oats emerged 7 days after sowing. There were no differences in the chlorophyll content and photosynthetic efficacy, regardless of the type of barley. There were no significant differences in total phenol, total flavonoid content, and DPPH radical scavenging activity between plants originating from IA and LTA, regardless of the type of barley. However, there were differences between some specific seeds. In particular, for malting barley the total flavonoid content differed in the order of Gangjin > Changwon > Haenam = Jeonju > Naju. The results indicate that crop growth, yield and content of secondary compounds in various types of barley may be affected by climate change.

• Journal of Korean Society of Forest Science
• /
• v.106 no.4
• /
• pp.388-396
• /
• 2017

This study was carried out to determine effects of bamboo species on the distribution of nutrients in aboveground biomass of Phyllostachys bambusoides and Phyllostachys nigra var. nenosis, Damyanggun, Korea. The study site was established around 40-year-ago to produce bamboo culm and edible shoot production. Total 28 bamboos (14 P. bambusoides and 14 P. nigra var. nenosis) were cut to measure nutrient concentration of each bamboo component, such as culm, branches and leaf. Magnesium concentration in each bamboo component was significantly higher in the P. bambusoides than in the P. nigra var. nenosis. Nutrient concentrations except for calcium were significantly higher in the current-year-old bamboos than in the > 1-year-old bamboos. The nutrient concentration in leaf was generally highest in carbon, followed by potassium or nitrogen, phosphorus, calcium or magnesium. Total nutrient content in each bamboo component was significantly higher in the P. bambusoides than in the P. nigra var. nenosis. The nutrient content of bamboo biomass was the highest in carbon, followed by potassium, nitrogen, phosphorus, magnesium and calcium. The results indicate that P. bambusoides uptakes more nutrients compared with P. nigra var. nenosis during growth development.