• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.211-220
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• 2021

Land Surface Temperature (LST) is one of the useful parameters to diagnose the growth and development of crop and to detect crop stress. Unmanned Aerial Vehicle (UAV)-based LST (LSTUAV) can be estimated in the regional spatial scale due to miniaturization of thermal infrared camera and development of UAV. Given that meteorological variable, type of instrument, and surface condition can affect the LSTUAV, the evaluation for accuracy of LSTUAV is required. The purpose of this study is to evaluate the accuracy of LSTUAV using LST measured at ground (LSTGround) under various meteorological conditions and growth phases of garlic crop. To evaluate the accuracy of LSTUAV, Relative humidity (RH), absolute humidity (AH), gust, and vegetation index were considered. Root mean square error (RMSE) after minimizing the bias between LSTUAV and LSTGround was 2.565℃ under above 60% of RH, and it was higher than that of 1.82℃ under the below 60% of RH. Therefore, LSTUAV measurement should be conducted under the below 60% of RH. The error depending on the gust and surface conditions was not statistically significant (p-value < 0.05). LSTUAV had reliable accuracy under the wind speed conditions that allow flight and reflected the crop condition. These results help to comprehend the accuracy of LSTUAV and to utilize it in the agriculture field.

• Journal of Life Science
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• v.32 no.2
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• pp.155-160
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• 2022

Kenaf (Hibiscus cannabinus L.), one of the four major fiber crops, is attracting attention for its efficient CO₂-absorbing ability and versatility for producing daily supplies, including textiles. In Korea, a new cultivar 'Jangdae' was established in 2013. The ease of cultivation and seed gathering of 'Jangdae' has led to its nationwide cultivation. However, evaluation of the bioactivities of the different parts of kenaf, and especially the 'Jangdae' cultivar, remains rudimentary. In this study, the antithrombosis and antioxidant activities of extracts prepared from different parts of the 'Jangdae' cultivar were evaluated by determining their effects on blood clot formation. Extracts prepared from seeds (HC-SD), seedpods (HC-SP), leaves (HC-L), stems (HC-S), and roots (HC-R) of the 'Jangdae' cultivar strongly inhibited blood clot formation. In particular, the HC-SD, HC-SP, and HC-S extracts showed strong inhibition against the coagulation factors prothrombin, and thrombin. The HC-SP extract showed strong antioxidant activities, such as scavenging ability against DPPH anion, ABTS cation, nitrite, and reducing power. Since blood clot formation is closely related to oxidative stress, the HC-SP extract could be developed as a novel anticoagulation and antioxidant resource. This is the first report of the antithrombosis activities of different parts of H. cannabinus L. cv. 'Jangdae'.

• Analytical Science and Technology
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• v.21 no.2
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• pp.148-157
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• 2008

To describe the lifetime prediction of gas turbine core parts serviced in some ten thousands rpms at over $1,000^{\circ}C$, the Larson-Miller Creep Curves, which are formed by creep rupture tests as the destructive experiment with parameters of stress and temperature, are used often, but not exact and reliable with errors of over some tens. On the other hand, this study shows a non-destructive method with increased accuracy and reliability. The SEM and TEM specimens were extracted by replica after polishing the local airfoil and root surfaces of the first stage scraped blade (bucket), serviced for 18,000 hours at $1,280^{\circ}C$ in Gas Turbines of Boryong. The observed TEM and SEM precipitates were digitalized for calculation of the average size. Here we could find the precipitate size grown from $0.45{\mu}m$ to $0.6{\mu}m$ during service and the grown precipitates to be still sound. From these results we could conclude that the scraped balde can be used for ten thous and hours additionally and for twenty thousand hours by additional heat treatments on the scraped blade.

• Journal of Plant Biotechnology
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• v.41 no.2
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• pp.81-88
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• 2014

Salt cress (Thellungiella halophila or Thellungiella parvula), species closely related to Arabidopsis thaliana, represents an extremophile adapted to harsh saline environments. To isolate salt-tolerance genes from this species, we constructed a cDNA library from roots and leaves of salt cress plants treated with 200 mM NaCl. This cDNA library was subsequently shuttled into the destination binary vector [driven by the cauliflower mosaic virus (CaMV) 35S promoter] designed for plant transformation and expression via recombination- assisted cloning. In total, 305,400 pools of transgenic BASTA-resistant lines were generated in Arabidopsis using either T. halophila or T. parvula cDNA libraries. These were used for functional screening of genes involved in salt tolerance. Among these pools, 168,500 pools were used for primary screening to date from which 7,157 lines showed apparent salt tolerant-phenotypes in the initial screen. A secondary screen has now identified 165 salt tolerant transgenic lines using 1,551 (10.6%) lines that emerged in the first screen. The prevalent phenotype in these lines includes accelerated seed germination often accompanied by faster root growth compared to WT Arabidopsis under salt stress condition. In addition, other lines showed non-typical development of stems and flowers compared to WT Arabidopsis. Based on the close relationship of the tolerant species to the target species we suggest this approach as an appropriate method for the large-scale identification of salt tolerance genes from salt cress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.214-221
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• 2020

Salinity is one of the major abiotic stressors that inhibits the growth, yield, and productivity of crop plants. Therefore, it is necessary to develop crops with increased salt tolerance for cultivation in saline soils such as is found in reclaimed land. The objective of this study was to develop a salt-tolerant silage rice line that grows on reclaimed land. In order to develop this salt-tolerant silage rice, we transferred Saltol, a major QTL associated with salt tolerance, from IR64-Saltol, a salt-tolerant indica variety, into Mogyang, a susceptible elite japonica variety. To determine the effect of salt stress, Mogyang and IR64-Saltol cultivars were grown on a medium containing various concentrations of NaCl in in vitro conditions. Shoot length was found to decrease with increasing salt concentrations, and root growth was almost arrested at NaCl concentrations over 50 mM in the Mogyang cultivar. Based on these preliminary results, we screened five salt-tolerant lines showing superior growth under salt stress conditions. Polymerase chain reaction and sequencing results showed that the introgression types of Saltol QTL were derived from the IR64-Saltol cultivar in almost all selected lines. Based on the observed growth and physiological characteristics, the new Saltol introgression lines showed higher salt tolerance compared to the Mogyang parental cultivar. The salt-tolerant lines identified in this study could be used as a genetic resource to improve rice salt tolerance.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.389-398
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• 1984

The effect of N forms ($NO_3{^-}-N$, $NH_4{^+}-N$) and concentrations (4, 8, $16meq/{\ell}$) which were changed at head formation stage on the tip-burn incidence of chinese cabbage was studied under the three levels (0, 8, 16 meq/l) of Ca. All of the plants grown on $NH_4{^+}-N$ showed the symptoms of tip-burn and low yields regardless of Ca levels. Roots of plants grown on $NH_4{^+}-N$ were severely damaged. The pH of the leachate from $NH_4{^+}-N$ pot was decreased to below pH 5. Plants which had been grown on $NH_4{^+}-N$ before the head formation stage, but changed to $NO_3{^-}-N$ were recovered from abnormal growth. But, the reverse showed the tip-burn symptoms. $NH_4{^+}-N$ treatments increased the T-N contents, but lowered K and Ca contents of inner leafblades. Icreased applications of Ca did not affect the T-N and K contents of the inner leafblades. $NH_4{^+}-N$ suppressed Ca translocation into the inner leaves from outer leaves after the head formation stage, but $NO_3{^-}-N$ accelarated it. Ca contents were much lower in leaves showing tip-burn symptoms than in healthy leaves. Internal rot which is a tip-burn symptom occuring after head formation were noted in plants applied with high concentration of $NO_3{^-}-N$ both before and after the head formation stage. Ca contents correlated well with the rates of Ca application, but there was no correlation between ca conents and internal rot incidence. Chinese cabbage tip-burn is not caused by Ca deficiency, as is commonly believed, but rather by the water stress (95% water contents in $NO_3{^-}$-fed plants, 91% in $NH_4{^+}$-fed plants) resulting from root damage caused by ammonium toxicity. Internal rot is also caused by excess applications of nitrogen, and is unaffected by calcium levels.

• Journal of Korea Foresty Energy
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• v.19 no.2
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• pp.93-101
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• 2000

Wood of Robinia pseudoacacia and bark of Populus alba$\times$P. glandulosa, Fraxinus rhynchophylla and Ulmus davidiana var. japonica were collected and extracted with acetone-water(7:3, v/v) in glass jar to examine whether its bioactive compounds exist. The concentrated extracts were fractionated with hexane, chloroform, ethylacetate and water, and then freeze-dried for column chromatography and bioactive tests. The isolated compounds were sakuranetin-5-O-$\beta$-D-glucopyranoside from Populus alba $\times$Pl glandulosa, 4--ethyoxy-(+)-leucorobinetinidin frm R. pseudoacacia and fraxetion from F. rhynchophylla and were characterized by $^1H$ and$^{13}C $ NMR and positive FAB-MS. Decay-resistant activity was expressed by weight loss ratio and hyphae growth inhibition in the wood dust agar medium inoculated wood rot fungi. R. pseudoacacia showed best anti-decaying property in both test and its methanol untreated samples, indicating higher activity than methanol treated samples in hyphae grwoth test. In antioxidative test, $\alpha$-tocopherol, one of natural antioxidants, and BHT, one of synthetic antioxidants, were used as references to cmpare with the antioxidant activities of the extacted fractions. Ethylacetate fraction of F. rhynchophylla bark indicated the hightest activity in this test and all fractions of R. pseudiacacia extractives also indicated higher activities compared with the other fractions. In the isolated compounds, aesculetin isolated from F. rhynchophylla bark showed best activity and followed by robonetinidin from R. pseudoacaica.

• Ecology and Resilient Infrastructure
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• v.5 no.3
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• pp.163-173
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• 2018

The biopolymer (BP) used in this study is mainly composed of xanthan gum and ${\beta}$-glucan derived from microorganism and has been introduced as a novel material for soil stabilization. However, the broad applicability of BP has been suggested in the field of geotechnical engineering while little information is available about the effects of BP on the vegetation. The goal of this study is to find the BP effects on the growth of Camelina sativa L. (Camelina) under drought condition. For more thorough evaluation of BP effects on the plant growth, we examined not only morphological but also physiological traits and gene expression patterns. After 25 days of drought treatment from germination in the soil amended with 0, 0.25, 0.5, and 1% BP, we observed that the BP concentration was strongly correlated the growth of Camelina. When plants were grown under drought stress, Camelina in 0.5% BP mixture showed better physiological parameters of the leaf stomatal conductance, electrolyte leakage and relative water content compared to those in control soil without BP. Plant recovery rate after re-watering was higher and the development of lateral root was lower in BP amended soil. RNA expression of Camelina leaf treated with/without drought for 7 and 10 days showed that aquaporin genes transporting solutes at bio-membrane, CsPIP1;4, 2;1, 2;6 and TIP1;2, 2;1, were induced more in the plants with BP amendment and drought treatment. These results suggest that the soil amended with BP has a positive effect on the transport of nutrients and waters into Camelina by improving water retention in soil under drought condition.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.354-364
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• 2020

This study was conducted to examine the potential of inducing salinity stress on cylindrical paper pot tomato seedlings to inhibit overgrowth. Potassium fertilizers, sulfate of potash (K₂SO₄), muriate of potash (KCl), and monopotassium phosphate (KH₂PO₄), were prepared as two solutions of (5 and 10) dS·m^-1 salinity level, respectively, to investigate the influence on tomato (Lycopersicon esculentum Mill.) seedling growth. We also investigated the adaptability and survivability of treated tomato seedlings with high-salinity potassium (10 dS·m^-1 KCl) to harsh environmental conditions (water deficit, low temperature, and storage conditions). Repeated addition of high-salinity level KCl, K₂SO₄, or KH₂PO₄ markedly decreased the dry matter of shoot and root, leaf area, and net assimilate rates (NAR) but increased the stem diameter of seedlings. Among the three sources, the relative growth rate of plant height (RGR_H) was most sensitive to KCl addition; increasing salinity levels of KCl solution decreased the RGR_H of seedlings. The compactness, which directly reflects the stocky growth index, increased in KCl or KH₂PO₄ treatments. After a week's water deficit, severely wilted seedlings were observed in control seedlings (untreated with KCl), but no wilted seedlings were observed in the KCl treated seedlings, and the relative water content (RWC) of the untreated seedlings significantly decreased by 23 %, while that of the pretreated seedlings only decreased by 8 %. The increase in ion leakage of KCl treated seedlings at low temperatures was less than that of untreated seedlings. Furthermore, there was far lower damage proportion on pretreated seedlings at (9, 12, and 15)℃ storage temperatures after 20 days, compared with on unpretreated seedlings. Our results suggest that high-salinity potassium fertilizer, especially KCl, is effective in preventing tomato seedling overgrowth, while it also improves tolerance.

• Journal of Plant Biology
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• v.37 no.3
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• pp.387-394
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• 1994

Effects of environmental factors of light, temperature, nitrogen sources and water stress were analyzed quantitatively on the nodule formation and nitrogen fixation activity of autumn olive plant (Elaeagnu$ umbellala Thunb.) during the seedling growth. Seedlings showed the maximum nitrogenase activity of $72.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ in the early nodulation stage. The relative growth rate and T/R ratio changed from $1.60%{\cdot}d^{-1}$ and 1.12 in the earlier stage to $3.75%{\cdot}d^{-1}$ and 2.31 in the later stage, respectively. light conditions of 20-25, 1015 and 4-6% resulted in decreases of 41, 54 and 71% of the nitrogenase activity, respectively. Nodules incubated in 15, 20, 25 and $30^{\circ}C$ showed the activities of 5.4, 24.7, 51.6 and $58.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ respectively. Pretreatment with low temperature ($15^{\circ}C$) followed incubation at $30^{\circ}C$ attained higher nitrogenase activity ($66.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$) than that with higher temperature ($35^{\circ}C$). The oxygen pressure above 16 kPa is necessary for saturation of the nodule activity, but the activity was inhibited severely by physical impact such as the exision or isolation of nodules from the root. The relative activities of early nodules grown in pH 5.5, 6.5 and 8.0 were 89, 100 and 40% and those grown in 1 and 3 mM of $NO_3\;and\;NH_4$ were 6, 1 and 68, 50%, respectively. Watering levels of 20, 50 and 100 mL during the seedling growth resulted in 35, 120 and 8 mg of nodule formation and 33.6, 58.4 and $8.4\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ of the nitrogenase activity, respectively. Water stress with 86% decrease of soil water content caused temporary wilting point of leaf and a complete disappearance of nitrogenase activity of nodules, though the water content and transpiration rate in plant were reduced to 90 and 53%, respectively.tively.