• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.112-117
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• 2000

This study was conducted to evaluate the drought tolerance of Japonica and Indica rice cultivars during germinating and seedling stages by using the polyethylene glycol (PEG) solution. Each 5 cultivars of Japonica and Indica were cultured from 14 days after seeding(DAS) to 21 DAS using the PEG solution in a moderate water potential (-0.63 MPa). The lengths of radicle and plumule during the germinating stage were inhibitied by the PEG treatment to about 50% and 85%, respectively. The application of PEG to the seedling of two rice types caused to inhibit the plant height and leaf age about 23 % and 10%, respectively. Shoot and root dry weights by PEG treatment were inhibited more severely in Japonica than those in Indica. The difference on delaying of leaf area expansion between both rice types was not found with treatment of PEG, while the leaf color was increased in both Japonica and Indica by 19.9% and 9.2%, respectively. The average photosynthetic ability was inhibited more in Japonica to 36.0% than did Indica to 27.9%. The stomatal conductance was severely affected by PEG treatment, and the degree was varied in both rice types, ranged with 80-85% in Japonica and 29.3-81.6% in Indica. These results indicate there is little relationship between seed germination and seedling growth under the stress of low water potential.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.490-502
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• 2022

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) disease in rice (Oryza sativa L.) and it is among the most destructive pathogen responsible for severe yield losses. Potential bacterial biocontrol agents (BCAs) with plant growth promotion (PGP) abilities can be applied to better manage the BLB disease and increase crop yield, compared to current conventional practices. Thus, this study aimed to isolate, screen, and identify potential BCAs with PGP abilities. Isolation of the BCAs was performed from internal plant tissues and rhizosphere soil of healthy and Xoo-infected rice. A total of 18 bacterial strains were successfully screened for in vitro antagonistic ability against Xoo, siderophore production and PGP potentials. Among the bacterial strains, 3 endophytes, Bacillus sp. strain USML8, Bacillus sp. strain USML9, and Bacillus sp. strain USMR1 which were isolated from diseased plants harbored the BCA traits and significantly reduced leaf blight severity of rice. Simultaneously, the endophytic BCAs also possessed plant growth promoting traits and were able to enhance rice growth. Application of the selected endophytes (BCAs-PGP) at the early growth stage of rice exhibited potential in suppressing BLB disease and promoting rice growth.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.239-239
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• 2017

The enhancement of leaf photosynthetic capacity can have the potential to improve the seed yield of soybean. Key targets for the increase of leaf photosynthetic capacity remains unclear in soybean. Peking, Chinese local variety, has been the useful material for soybean breeding since it shows various resistances against biotic and abiotic stress. Sakoda et al., 2017 reported that Peking had the higher capacity of leaf photosynthesis than Enrei, Japanese elite cultivar. They identified the genetic factors related to high photosynthetic capacity of Peking. The objective of this study is to elucidate the physiological basis underlying high photosynthetic capacity of Peking. Peking and Enrei were cultivated at the experimental field of the Graduate School of Agriculture, Kyoto University, Kyoto, Japan. The sowing date was July 4, 2016. Gas exchange parameters were evaluated at the uppermost fully expanded leaves on 43, 49, and 59 days after planting (DAP) with a portable gas exchange system, LI-6400. The leaf hydraulic conductance, $K_{leaf}$, was determined based on the water potential and transpiration rate of the uppermost fully expanded leaves on 60 DAP. The morphological traits related to leaf photosynthesis were analyzed at the same leaves with the gas exchange measurements. The light-saturated $CO_2$ assimilation rate ($A_{sat}$) of Peking was significantly higher than that of Enrei at 43 and 59 DAP while the stomatal conductance ($g_s$) of Peking was significantly higher at all the measurements (p < 0.05). It suggested that high $A_{sat}$ was mainly attributed to high $g_s$ in Peking. $g_s$ is reported to be affected by the morphological traits and water status inside the leaf, represented by $K_{leaf}$, in crop plants. The tendency of the variation of the stomatal density between two cultivars was not consistent throughout the measurements. On the other hand, $K_{leaf}$ of Peking was 59.0% higher than that of Enrei on 60 DAP. These results imply that high $g_s$ might be attributed to high $K_{leaf}$ in Peking. Further research is needed to reveal the mechanism to archive high $g_s$ on the basis of water physiology in Peking. The knowledge combining the genetic and physiological basis underlying high photosynthetic capacity of Peking can be useful to improve the biomass productivity of soybean.

• Korean journal of food and cookery science
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• v.31 no.3
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• pp.335-343
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• 2015

The aim of this investigation was to examine the antioxidation, physicochemical, and sensory activity of a Korean steamed-rice cake, Sulgidduk, fortified with water extracts from Moringa oleifera (M. oleifera) leaf. M. oleifera leaf extracts were added to rice powder at rations of 0.1%, 1% and 10%. To examine antioxidation properties, the scavenging activities of DPPH radicals, hydroxyl radicals, ABTS+ radicals, and ferric ion reducing antioxidant power were investigated. M. oleifera extracts significantly increased the antioxidation activities of Sulgidduk in a dose dependent manner (p<0.05). Physicochemical characteristics were measured by proximate composition, color, texture profile analysis, and sensory evaluations. As the concentration of M. oleifera leaf extracts increased, L-values and a-values significantly decreased while b-values increased. Texture profile analysis demonstrated that the control groups showed significantly higher values for hardness, cohesiveness, chewiness, and adhesiveness as compared with groups containing M. oleifera leaf extract (p<0.05). In the sensory evaluation, the sample containing 0.1% of M. oleifera leaf extract obtained the best results in overall preference. Taken together, these results suggest that M. oleifera leaf may have the potential to increase the consumer acceptability and the functionality of Sulgidduk.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.241-249
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• 1994

Leaf diffusive resistance (LDR), stomatal density, length of guard cell and hair density of leaves of 6 oak species were determined under withdrawal of water, and their strategies of drought stress were analyzed by principal component analysis. LDR of Quercus acutissima, Q. aliena and Q. serrata increased earlier than those of the other species at high leaf water potential $({\Psi}_{leaf})$ or low water saturation deficit (WSD), which was an avoidance mechanism reducing damage by water stress. Q. variabilis with low stomatal density, small stomatal size and high hair density had avoidance mechanisms increasing LDR at high $({\Psi}_{leaf})$ However, Q. mongolica and Q. dentata increased LDR at low $({\Psi}_{leaf})$ as xeric species do. Results from principal component analysis on the 15 variables related to strategies of drought stress indicated that the 6 oak species were divided into 2 groups: (1) Q. acutissima, Q. aliena and Q. serrata as mesic habitat species and (2) Q. variabilis, Q. mongolica and Q. dentata as xeric habitat species. Among three xeric species Q. acutissima differed from the other two species in the drought strategies such as high hair density, low stornatal density, high leaf area ratio, stomatal closing at low $({\Psi}_{leaf})$ and small cell wall elasticity. The results could reasonably explain their drought strategies in natural habitat.

• Biomolecules & Therapeutics
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• v.11 no.3
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• pp.200-203
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• 2003

The present study was carried out to investigate the potential acute toxicity of bamboo leaf water extract by a single oral dose in Sprague-Dawley rats. Twenty male and female rats aged 5 weeks were randomly assigned to four groups of 5 rats each and were administered singly by gavage at dose levels of 0, 1250, 2500, or 5000 mg/kg body weight. Mortalities, clinical findings, and body weight changes were monitored for the l4-day period following the administration. At the end of 14-day observation period, all animals were sacrificed and complete gross postmortem examinations were performed. Throughout the study period, no treatment-related deaths were observed. There were no adverse effects on clinical signs, body weight, and gross finding at any dose tested. The results showed that the single oral administration of bamboo leaf water extract did not induce any toxic effect at a dose level of below 5000 mg/kg in rats and that the minimal lethal dose were considered to be over 5000 mg/kg body weight for both sexes.

• Mycobiology
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• v.44 no.2
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• pp.85-92
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• 2016

Mycoherbicides are exclusive biotechnology products which offer a non-chemical solution to control noxious weeds on the land as well as aquatic in systems, viz a viz saving environment from hazardous impact of synthetic chemicals. The present paper highlights the mycobiota associated with Eichhornia crassipes infesting Harike wetland area of Punjab and evaluation of their pathogenic potential for futuristic application as a mycoherbicide. Of the 20 isolates tested by leaf detached assay and whole plant bioassays, only one isolate (#8 BJSSL) caused 100% damage to E. crassipes. Further, the culture filtrate of this isolate also exhibited a similar damage to the leaves in an in vitro detached leaf assay. The potential isolate was identified as Phaeoacremonium italicum using classical and modern molecular methods. This is the first report of P. italicum as a pathogen of E. crassipes and of its potential use as a biological control agent for the management of water hyacinth.

• Korean Journal of Plant Resources
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• v.7 no.1
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• pp.97-101
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• 1994

The effects of NaCl salinity on the leaf photosynthesis and water relation of two cultivars of rice(Oryza sativa L.) , the salt-tolerant cultivar Seohae and the salt-senstive cultivar Iri-380 were exam-ined. Two cultivars of rice were grown for 14 days in nutrient solution at SOmM NaCl. Comparing theieaf Na content of two cultlvars, Seohae showed high accumulation of Na content in the leaf blade, while Iri-380 showed low. The Na content in leaf blade reduced the rate of leaf photosynthesis. Salt-tolerant cultivar Seohae was less decreased the rate of leaf photosynthesis than salt- sensitive cultivarIri-380. And Seohae showed larger decreased the osmotic potential in the leaves than Iri-380. This in-dicates that in the salt-tolerant cultivar, osmotic adjustment is developed under saliniEation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.35-35
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• 2017

How do plants take up water from soils especially when water is scarce in soils? Plants have a strategy to respond to water deficit to manage water necessary for their survival and growth. Plants regulate water transport inside them. Water flows inside the plant via (i) apoplastic pathway including xylem vessel and cell wall and (ii) cell-to-cell pathway including water channels sitting in cell membrane (aquaporins). Water transport across the root and leaf is explained by a composite transport model including those pathways. Modification of the components in those pathways to change their hydraulic conductivity can regulate water uptake and management. Apoplastic barrier is modified by producing Casparian band and suberin lamellae. These structures contain suberin known to be hydrophobic. Barley roots with more suberin content from the apoplast showed lower root hydraulic conductivity. Root hydraulic conductivity was measured by a root pressure probe. Plant root builds apoplastic barrier to prevent water loss into dry soil. Water transport in plant is also regulated in the cell-to-cell pathway via aquaporin, which has received a great attention after its discovery in early 1990s. Aquaporins in plants are known to open or close to regulate water transport in response to biotic and/or abiotic stresses including water deficit. Aquaporins in a corn leaf were opened by illumination in the beginning, however, closed in response to the following leaf water potential decrease. The evidence was provided by cell hydraulic conductivity measurement using a cell pressure probe. Changing the hydraulic conductivity of plant organ such as root and leaf has an impact not only on the speed of water transport across the plant but also on the water potential inside the plant, which means plant water uptake pattern from soil could be differentiated. This was demonstrated by a computer simulation with 3-D root structure having root hydraulic conductivity information and soil. The model study indicated that the root hydraulic conductivity plays an important role to determine the water uptake from soil with suboptimal water, although soil hydraulic conductivity also interplayed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.10a
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• pp.175-176
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• 2003