• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1763-1772
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• 2017

This study aimed to isolate and characterize antibacterial metabolites from Pharbitis nil seeds and investigate their antibacterial activity against various plant pathogenic bacteria. The methanol extract of P. nil seeds showed the strongest activity against Xanthomonas arboricola pv. pruni (Xap) with a minimum inhibition concentration (MIC) value of $250{\mu}g/ml$. Among the three solvent layers obtained from the methanol extract of P. nil seeds, only the butanol layer displayed the activity with an MIC value of $125{\mu}g/ml$ against Xap. An antibacterial fraction was obtained from P. nil seeds by repeated column chromatography and identified as pharbitin, a crude resin glycoside, by instrumental analysis. The antibacterial activity of pharbitin was tested in vitro against 14 phytopathogenic bacteria, and it was found to inhibit Ralstonia solanacearum and four Xanthomonas species. The minimum inhibitory concentration values against the five bacteria were $125-500{\mu}g/ml$ for the n-butanol layer and $31.25-125{\mu}g/ml$ for pharbitin. In a detached peach leaf assay, it effectively suppressed the development of bacterial leaf spot, with a control value of 87.5% at $500{\mu}g/ml$. In addition, pharbitin strongly reduced the development of bacterial wilt on tomato seedlings by 97.4% at $250{\mu}g/ml$, 7 days after inoculation. These findings suggest that the crude extract of P. nil seeds can be used as an alternative biopesticide for the control of plant diseases caused by R. solanacearum and Xanthomonas spp. This is the first report on the antibacterial activity of pharbitin against phytopathogenic bacteria.

• Research in Plant Disease
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• v.20 no.2
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• pp.71-78
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• 2014

Gamma irradiation and its convergence with nano-silver particles and sodium dichloroisocyanurate (NaDCC) were investigated to inhibit germination and mycelial growth of Botrytis elliptica, the pathogen of lily leaf blight. In addition, the same treatments were studied on the process of disease development with detached leaf of lily cv. Siberia. Spray inoculation, which is closer to natural infection than wound inoculation, can be a way to investigate infection ability of the treated pathogen. The irradiating dose required to reduce the population by 90%, $D_{10}$, was 526 Gy irradiating with 0-2000 Gy gamma ray on the conidial suspension as well as the growing mycelia. Even at 2000 Gy, the mycelium was not killed but just delayed its growth at 1-2 days behind. Convergent treatment with 40 mg/l of NaDCC just before 200 Gy gamma irradiation was the best way to decrease the conidial germination about 1/1000 times. The control values of gamma irradiation were 23% and 19.5% at wound inoculation and spray inoculation, respectively. On wound-inoculation, the control value of NaDCC only was 89%, and that of NaDCC convergent with 200 Gy gamma irradiation was 32%. On sprayinoculation, the highest control value was NaDCC at 50%, and that of NaDCC convergent with gamma irradiation was 24%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.4
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• pp.38-44
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• 1979

$^14$C-sucrose was labeled on detached panicles and $^14{CO}_2$ on flag leaves or panicles of intact plants to study grain sink activity in spring oats cultivar Pennfield. Defoliation and emasculation experiment was conducted to study source-sink relationship during grain filling. Specific activity of groat rose up to 15 days after anthesis and declined rapidly to 18 days. Daily gain of groat wt. matched closely with specific activity of. groat during grain filling. Primary groats were higher in specific activity of groat than secondary groats.$^14{CO}_2$ exposure on panicle was three times higher in specific activity of groat than $^14{CO}_2$exposure on flag leaf. In the defoliation and emasculation experiment, groat wt. of Pennfield oats decreased as ratio of source/sink decreased. Half number of spikelets with half leaf area was no different in groat wt. compared to control, but normal number of spikelets with zero leaf area was decreased 16% in groat wt., indicating a significant compensation by green area on panicle.

• Journal of Plant Biotechnology
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• v.50
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• pp.169-175
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• 2023

A plant regeneration system was developed through shoot organogenesis from in vitro leaf explants of Chrysanthemum morifolium 'Ohblang'. The effects of different concentrations of plant growth regulators and AgNO₃ on efficient shoot regeneration and inhibition of browning were evaluated in chrysanthemum. The explants were cultured on MS shoot induction medium supplemented with 12 combination treatments of 6-benzyladenine (BA) 0.5, 1.0 and 2.0 mg/L, and α-naphthaleneacetic acid (NAA) 0.2, 0.5, 1.0 and 2.0 mg/L in darkness for 6 weeks and cultured under a 16/8 h photoperiod for 6 weeks. The highest shoot regeneration was obtained from the explants cultured on the medium with 1.0 mg/L BA and 1.0 mg/L NAA. Based on this result, AgNO₃ was added to a shoot induction medium containing MS salts, vitamins, 1.0 mg/L BA, 1.0 mg/L NAA, 30 g/L sucrose, and 6 g/L agar to reduce browning of chrysanthemum leaf explants. In the control treatment without AgNO₃, leaf explants turned brown at the cut edge; however, browning was not observed in AgNO₃ treatments. Shoot organogenesis was higher at low concentrations of AgNO₃ and decreased with an increase in AgNO₃ concentration. The explants cultured on shoot induction medium (MS salts, vitamins, 1.0 mg/L BA, 1.0 mg/L NAA) with 1 mg/L of AgNO₃ produced the highest shoot regeneration with 2.6 shoots per explants and a browning index of 0.7. When the regenerated shoots were detached from the explants and cultured on MS medium, the shoots were elongated and rooted successfully.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.386-396
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• 2013

Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide ($H_2O_2$) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion ($O_2{^-}$) and $H_2O_2$ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of $H_2O_2$ and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both $H_2O_2$ and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by $10^6$ and $10^7$ cfu/ml of R. solanacearum. $H_2O_2$- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by $H_2O_2$ and/or SNP with untreated control. Neither $H_2O_2$ nor SNP protect the tomato seedlings from the bacterial wilt, but $H_2O_2$ + SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that $H_2O_2$ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

• Proceedings of the Ginseng society Conference
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• 1974.09a
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• pp.9-22
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• 1974

Unlike the tissue culture in animals and human being, in higher plants various parts of the plant are cultured for varied purposes, and they are named variously depending on which parts are used as explants or what purposes they are cultured for. Followings are some of the names of culture used frequently: organ culture, tissue culture, callus culture, single cell culture, meristem culture, mericlone culture, ovary culture, ovule culture, embryo culture, endosperm culture, anther culture, pollen culture, protoplast culture, etc.. As the names of the culture indicate, in some kinds of culture the explants used for culture are actually not tissues, but organs, single cells, or protoplasts. It seems, however, convenient to call all of the above-mentioned cultures grossly as tissue culture. Several kinds of tissue culture were attempted using Panax ginseng as material and some of the results were summarized below. 1. Callus culture After dormancy of the sed was broken, whole embryo or parts (hypocotyl, cotyledon and epicotyl) of partly grown embryo were cultured in the media supplemented with growth regulators. Rapid swelling occurred in a few weeks, but most of the swelling was observed only in the basal part of epicotyl, changes in the other parts of embryo appearing in much later stages. The swelling or increase in size, however, was resulted not from the divisions of cells, but from the mere expansion of cell. Real calli were formed about two months after inoculation of explants. Callus tissues developed from cortex, pith, and vascular bundle in the cases of hypo- and epicotyl, from mesophyl tissue in the case of cotyledon. Shoots developed more easily from cotyledons regardless of whether they are detached from or attached to the embryo proper. 2. Culture in the Knudson C medium When cotyledons, detached from or attached to the embryo proper, were cultured in the growth regulator-free Knudson C medium comprision only several kinds of mineral compounds and sucrose, shoot primordium or callus developed profusely and finally plantlets were produced directly from shoot primordium or indirectly through callus. In this medium epidermal cells as well as mesophyl cells of the cotyledon became meristematic and divided, changing into multinucleate cells or multicellular bodies, developing eventually into either shoot primordia or calli. 3. Anther culture Anthers were cultured in the media supplemented with various growth regulators applied singly or in combinations. Callus was formed mostly in the connective tissue of anther. Cells of anther wall layers changed in appearance, but no division occurred. Microspores of all stages in development were not changed, ruling out the possibility that microspore-originated callus might be formed. 4. Isolation of protoplast Protoplasts were isolated from young root, leaf, and epicotyl, using 0.7M D-mannitols as osmoticum and using macerozyme and cellulase respectively for maceration and digestion of the cell wall. Production in large number of naked intact protoplast was rather difficult as compared with other plant species. Fusion of protoplasts occurred infrequently mainly due to the fewer number of naked protoplasts in the solution.

• BMB Reports
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• v.33 no.3
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• pp.256-262
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• 2000

In this study the disassembly process of chlorophyII (ChI)protein complexes of a stay-green mutant (ore10 of Arabidopsis thaliana) was investigated during the dark incubation of detached leaves. During this dark-induced senescence (DIS), the Chi loss was delayed in the mutant, while the photochemical efficiency of photosystem II (PSII) or Fv/Fm was accelerated when compared with the wild type (WT) leaves. This indicates that the decrease in Fv/Fm is a separate process and not causally-linked to the degradation of Chi during DIS of Arabidopsis leaves. In the native green gel electrophoresis of the Chi-protein complexes, which was combined with an additional twodimensional SDS-PAGE analysis, the delayed senescence of this mutant was characterized by the appearance of an aggregate at 1 d or 2 d, as well as very stable light harvesting complex II (LHCII) trimers until 5 d after the start of DIS. The polypeptide composition of the aggregates varied during the whole DIS at 5 d. Dl protein appeared to be missing in the aggregates. This result supports the idea of a faster depletion of functional PSH in the mutants compared with WT, as suggested by the earlier reduction of Fv/Fm and the stable Chl a/b ratio in the mutants. At 5 d, the WT leaves also often showed aggregates, but the polypeptide composition was different from those of ore10. The results presented suggest that the formation of aggregates, or stable LHCII trimers in the stay-green mutants, is a way to structurally protect Chi-protein complexes from serious proteolytic degradation. Detailed disassembly processes of Chi-protein complexes in WT and ore10 mutants are discussed.

• The Korean Journal of Mycology
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• v.34 no.2
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• pp.112-118
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• 2006

To select efficient entomopathogenic fungal strains of Lecanicillium for the biocontrol of aphid, Myzus persicae, conidial suspension ($1{\times}10\;conidia/ml$) was sprayed onto a detached Chinese cabbage leaf in a petri dish with a dampened filter paper that had 20 nymphs of aphid. Lecancillium strain 4078 and 6543 were the best strains for the biocontrol of aphid at high temperature of $30^{\circ}C$ and low relative humidity (RH) of 85%, respectively. The cumulative mortality of strain 4078 at $30^{\circ}C$ after 3 days was 100% and that of strain 6543 was 90% at 85% RH after 5 days. Strain 4078 also exhibited almost 100% germination ratio of conidia and high rate of mycelial growth at the broad temperature-range of $15{\sim}25^{\circ}C$. The strain 4078 and 6543 were all identified as Lecanicillium species based on the DNA sequences (accession no.: EF026004 and EF026005, respectively) of the ITS regions of the fungi. Excellent production of aerial conidia of strain 6543 was accomplished by using steamed polished rice as the solid culture medium.

• Publications of The Korean Astronomical Society
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• v.36 no.3
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• pp.65-78
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• 2021

Jagyeokru, an automatic striking water clock described in the Sejong Sillok (Veritable Records of King Sejong) is essentially composed of a water quantity control device and a time-signal device, with the former controlling the amount or the flow rate of water and the latter automatically informing the time based on the former. What connects these two parts is a signal generating device or a power transmission device called the 'Jujeon' system, which includes a copper rod on the float and ball-racked scheduled plates. The copper products excavated under Gongpyeong-dong in Seoul include a lot of broken plate pieces and cylinder-like devices. If some plate pieces are put together, a large square plate with circular holes located in a zigzag can be completed, and at the upper right of it is carved 'the first scheduled plate (一箭).' Cylinder-like devices generally 3.8 cm in diameter are able to release a ball, and have a ginkgo leaf-like screen fixed on the inner axis and a bird-shaped hook of which the leg fixes another axis and the beak attaches to the leaf side. The lateral view of this cylinder-like device appears like a trapezoid and mounts an iron ball. The function of releasing a ball agrees with the description of Borugak Pavilion, where Jagyeokru was installed, written by Kim Don (1385 ~ 1440). The other accounts of Borugak Pavilion's and Heumgyeonggak Pavilion's water clocks describe these copper plates and ball releasing devices as the 'Jujeon' system. According to the description of Borugak Pavilion, a square wooden column has copper plates on the left and right sides the same height as the column, and the left copper plate has 12 drilled holes to keep the time of a 12 double-hours. Meanwhile, the right plate has 25 holes which represent seasonal night 5-hours (Kyeong) and their 5-subhours (Jeom), not 12 hours. There are 11 scheduled plates for seasonal night 5-hours made with copper, which are made to be attached or detached as the season. In accordance with Nujutongui (manual for the operation of the yardstick for the clepsydra), the first scheduled plate for the night is used from the winter solstice (冬至) to 2 days after Daehan (大寒), and from 4 days before Soseol (小雪) to a day before the winter solstice. Besides the first scheduled plate, we confirm discovering a third scheduled plate and a sixth scheduled plate among the excavated copper materials based on the spacing between holes. On the other hand, the width of the scheduled plate is different for these artifacts, measured as 144 mm compared to the description of the Borugak Pavilion, which is recorded as 51 mm. From this perspective, they may be the scheduled plates for the Heumgyeonggak Ongru made in 1438 (or 1554) or for the new Fortress Pavilion installed in Changdeokgung palace completed in 1536 (the 31^st year of the reign of King Jungjong) in the early Joseon dynasty. This study presents the concept of the scheduled plates described in the literature, including their new operating mechanism. In addition, a detailed model of 11 scheduled plates is designed from the records and on the excavated relics. It is expected that this study will aid in efforts to restore and reconstruct the automatic water clocks of the early Joseon dynasty.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.240-255
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• 2012

The objectives of this study were to investigate the levels of phytotoxicity of rice varieties to HPPD (4-hydroxy phenylpyruvate dioxygenase)-inhibiting herbicides known for their efficiency to control the sulfonylureas-resistant weed species：mestrione, benzobicyclone, and tefuryltrione. The twenty-six rice varieties (8-Japonica ${\times}$ Indica-type varieties and 18-Japonica-type varieties) were grown for 25 days on seedling trays and then transplanted to paddy rice fields followed by herbicide treatment i.e. standard and double doses of there respective herbicides at 5, 10, and 15 days after transplanting. Although mestrione, benzobicyclone and tefuryltrione are all HPPD-inhibiting herbicides, the phytotoxicity symptoms of the different rice varieties based on the timing of application and doses of the herbicides were significantly different. The Japonica ${\times}$ Indica-type varieties showed much more phytotoxicity symptoms than Japonica-type varieties in all applied herbicides. Increasing herbicidal doses of mesotrione, and an earlier application of and increasing herbicidal doses of benzobicyclon caused severe phytotoxicity symptoms. On the other hand, phytotoxicity due to tefuryltrione did not exhibit significant differences between rice varieties in either the timing of application or dose of the herbicide. Regardless of timing of application and dose of the herbicides, Hangangchalbyeo-1, Hyangmibyeo-1 and high-yield rice varieties such as Namcheonbyeo, Dasanbyeo, Areumbyeo, and Hanareumbyeo, which belong to the Japonica ${\times}$ Indica-type varieties, showed 5 to 8 levels of phytotoxicity symptoms including albinism, browning, detached leaf, and necrosis to mesotrione and benzobicyclon whereas only 1 to 3 levels of phytotoxicity symptoms (chlorosis, albinism, and browning) were seen with to tefuryltrione application. The Japonica-type varieties exhibited only slight phytotoxicity symptoms (1~2 levels) in conformity with the timing of application and doses of the herbicides. However, there were significant differences among the Japonica-type rice varieties, depending on the type of herbicide. Thirteen-Japonica type rice varieties were sensitive to benzobicyclone while 4-Japonica-type and 7-Japonica-type varieties showed phytotoxicity symptoms such as chlorosis and albinism with mestrione and tefuryltrione application, respectively. Therefore, we suggest that the combined-type herbicides including mestrione, benzobicyclone and tefuryltrione should be rejected in paddy fields where rice is grown for either human consumption (functional or processed rice) or livestock feed because of severe phytotoxicity symptoms on the various rice varieties seen regardless of the timing of application and doses of the herbicides.