• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.522-530
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• 2018

Brachypodium distachyon has been developed as a monocot model plant for temperate grasses and bioenergy crops. Although B. distachyon research is moving forward rapidly, the study of photoresponses has not been explored. To extend our knowledge of responses to light in monocots, we performed photoresponse analysis of B. distachyon using two inbred lines, Bd21 and Bd21-3. In this study, we first compared growing phenotypes between the two lines and investigated coleoptile and primary leaf growths under dark, far-red, red, and white light conditions. The results showed that the growth of the two lines were similar until tillering stage, but other developmental stages from heading to senescence were much delayed in Bd21-3, which resulted in increased height and tiller numbers. Under different light conditions, primary leaf lengths were kept increasing during the growth period, whereas the coleoptile extension was inhibited 4 to 7 days after growth depending on the light conditions applied. These results suggest that the responses to light in B. distachyon can be examined by measuring coleoptile lengths approximately 7 days after seedling growth. Moreover, we selected light-responsive genes known in Arabidopsis thaliana, such as chlorophyll A/B binding protein (CAB), light-harvesting chlorophyll binding protein (Lhcb) and chalcone synthase (CHS), and confirmed their light-induced gene expression in B. distachyon. Therefore, the present study suggests that the inhibition of coleoptile growth can be used as the parameter to analyze photoresponses in the monocot model plant, and also provide the reference genes whose expression is induced by far-red and red light treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.149-153
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• 1999

Prediction of rice developmental stage is necessary for proper crop management and a prerequisite for growth simulation as well. The objectives of the present study were to find out the relationship between the plastochrone index(PI) and the developmental index(DVI) estimated by non-parametric phenology model which simulates the duration from seedling emergence(DVI=0) to heading(DVI=l) by employing daily mean air temperature and daylength as predictor variables, and to confirm the correspondency of developmental indice to panicle developmental stages based on this relationship. Four japonica rice cultivars, Kwanakbyeo, Sangpungbyeo, Dongjinbyeo, and Palgumbyeo which range from very early to very late in maturity, were grown by sowing directly in dry paddy field five times at an interval of two weeks. Data for seedling emergence, leaf appearance, differentiation stage of primary rachis branch and heading were collected. The non-parametric phenology model predicted well the duration from seedling emergence to heading with errors of less than three days in all sowings and cultivars. PI was calculated for every leaf appearance and related to the developmental index estimated for corresponding PI. The stepwise polynomial analysis produced highly significant square-rooted cubic or biquadratic equations depending on cultivars, and highly significant square-rooted biquadratic equation for pooled data across cultivars without any considerable reduction in accuracy compared to that for each cultivar. To confirm the applicability of this equation in predicting the panicle developmental stage, DVI at differentiation stage of primary rachis branch primordium was calculated by substituting PI with 82 corresponding to this stage, and the duration reaching this DVI from seedling emergence was estimated. The estimated duration revealed a good agreement with that observed in all sowings and cultivars. The deviations between the estimated and the observed were not greater than three days, and significant difference in accuracy was not found for predicting this developmental stage between those equations derived for each cultivar and for pooled data across all cultivars tested.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.125-135
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• 2014

A population model of bacterial spot caused by Xanthomonas campestris pv. vesicatoria on hot pepper was developed to predict the primary disease infection date. The model estimated the pathogen population on the surface and within the leaf of the host based on the wetness period and temperature. For successful infection, at least 5,000 cells/ml of the bacterial population were required. Also, wind and rain were necessary according to regression analyses of the monitored data. Bacterial spot on the model is initiated when the pathogen population exceeds $10^{15}cells/g$ within the leaf. The developed model was validated using 94 assessed samples from 2000 to 2007 obtained from monitored fields. Based on the validation study, the predicted initial infection dates varied based on the year rather than the location. Differences in initial infection dates between the model predictions and the monitored data in the field were minimal. For example, predicted infection dates for 7 locations were within the same month as the actual infection dates, 11 locations were within 1 month of the actual infection, and only 3 locations were more than 2 months apart from the actual infection. The predicted infection dates were mapped from 2009 to 2012; 2011 was the most severe year. Although the model was not sensitive enough to predict disease severity of less than 0.1% in the field, our model predicted bacterial spot severity of 1% or more. Therefore, this model can be applied in the field to determine when bacterial spot control is required.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.57-62
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• 2006

Several methods for determining the response of corn to glyphosate were investigated to provide a fast and reliable method for identifying glyphosate-resistant corn in vivo. Two bioassays were developed. One assay is named 'whole plant / leaf growth assay', in which the herbicide glyphosate is applied on the upper part of 3rd leaf and the growth of herbicide-untreated 4th leaf is measured at 3 day after treatment. in this assay, the leaf growth of conventional corn was inhibited in a dose dependent from 50 to $1600{\mu}g/mL$ of glyphosate and growth inhibition at $1600{\mu}g/mL$ was 55% of untreated control. The assay has the potential to be used especially in the case that the primary cause of glyphosate resistance is related with a reduction of the herbicide translocation. Another assay is named 'leaf segment / shikimate accumulation assay', in which the four excised leaf segments ($4{\times}4mm$) are placed in each well of a 48-well microtiter plate containing $200{\mu}L$ test solution and the amount of shikimate is determined after incubation for 24 h in continuous light at $25^{\circ}C$. In this assay, 0.33% sucrose added to basic test solution enhanced a shikimate accumulation by 3 to 4 times and the shikimate accumulation was linearly occurred from 2 to $8{\mu}g/mL$ of glyphosate, showing an improved response to the method described by Shaner et al. (2005). The leaf segment / shikimate accumulation assay is simple and robust and has the potential to be used as a high throughput assay in the case that the primary cause of glyphosate resistance is related with EPSPS, target site of the herbicide. Taken together, these two assays would be highly useful to initially select the lines obtained after transformation, to investigate the migration of glyphosate-resistant gene into other weeds and to detect a weedy glyphosate-resistant corn in field.

• Culinary science and hospitality research
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• v.19 no.4
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• pp.1-12
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• 2013

The purpose of this study was to find the effects of guava leaf powder as a natural tenderizing ingredient for low-fat pork seasoned with meat sauce, and to promote a consumer demand and practical use of low-fat pork. Moisture content, pH, color, texture, and sensory tests (quantitative descriptive sensory evaluations and acceptance) were conducted to the control and 5 samples of pork seasoned with 0.75, 1, 1.5, 2, 3% guava leaf powder) to determine the highest effectiveness on tenderizing pork. Moisture content and pH values were the highest in the samples with 1% and 1.5% of guava leaf powder added. L-value of cooked meat decreased, while a-value increased. In the texture test, most of the experiments showed the best values in the sample with 1.5% added. Based on quantitative descriptive sensory evaluations, the unpleasant smell of meat tended to decrease with more guava leaf powder, and the scores of the others were highest in the sample with 1.5% added. This sample also got the highest score in the acceptance test. These results can be used as primary data for research on the tenderizing effect of a functional ingredient and solutions to unbalanced consumption of pork.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.26-32
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• 1988

This study was conducted to determine the effects of cutting frequency and cutting height on agronomic characteristics and yield performance of sorghum-sudangrass hybrid, cv. Pioneer 855 F on the experimental field of Livestock Experiment Station, Suweon. The results are summarized as follows: 1. The relative contribution of leaf component to total yield was higher when the plants were cut frequently rather than when defoliated only a few times, and tend to be higher with high cutting. 2. Leaf Area Index (LAI) was the highest at the primary growth of two cutting times scheme and the first regrowth for three or four cutting times a year, but LAI, in general, was not related to cutting height. 3. Crop Growth Rate was the heighest at the first regrowth-plants grown in summer, and it was also related to the amount of stubble left at the previous cut. 4. Dead stubbles were not occurred when plants were cut before heading, but those were accompanied by the frequent and low cutting. 5. Total fresh fodder and dry matter yield were the highest at two times cut a year, and decreased with frequent cutting. The optimum cutting height at two times cut was ca. lOCm height stubble from the ground level, but yield increased with higher level cutting at the three or four times cut a year.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.236-243
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• 2009

The halophyte Leymus chinensis (Trin.) is a perennial rhizome grass (tribe Gramineae) that is widely distributed throughout China, Mongolia and Siberia. This study was conducted to investigate an optimal condition for plant regeneration from mature seeds, leaf base segments, and root segments in L. chinensis. Plant growth regulators affecting embryogenic callus induction and plant regeneration were investigated by four-factor-three-level [L9 (34)] orthogonal test in this study. The effects of explants types (mature seeds, leaf base segments and root segments), callus types, medium types were examined in this study. Wild type (WT) and Jisheng No. 1 plants (JS) were used for primary callus induction. A clear explants difference was seen during callus induction; mature seeds were considered as the preferred explants; and the highest frequency of callus induction was obtained in Medium 6 using mature seeds as explants in WT. Plant regeneration ability was evaluated by frequencies of green callus forming, shooting, rooting, and shooting with roots. Effect of α-naphthalene acetic acid (NAA) on shoot regeneration was remarkable with the highest frequency of 70.8% in WT after 2-month culture. The medium with 0.2- 0.5 mg/L NAA was found to have the highest shoot induction. All regenerated shoots were successfully rooted when transferred on half-strength Murashige and Skoog (MS) basal medium. The acclimatized plantlets were grown to mature with flowering and seeds setting in green house conditions.

• Research in Plant Disease
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• v.13 no.1
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• pp.30-33
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• 2007

One hundred and eighty-six leaves of soybean cv. Seokryangputkong that showed mild mosaic symptoms were collected randomly and ELISA tests were conducted with those leaf samples to screen the presence of Cowpea mosaic virus (CPMV). Ninety-three out of 186 samples reacted positively to CPMV, but those samples did negatively to Soybean mosaic virus (SMV). At least, 55 leaf samples revealed higher values than that of positive control. The results strongly confirmed that CPMV occurred severely in soybean cv. Seokryangputkong. However, a question is raised on the primary reservoir and vector for transmission of this virus. Since the farmer changes seeds every year, seed transmission is excluded. The virus was also purified, the analysis of coat protein conformed the virus of cowpea mosaic virus and UV absorption pattern confirmed that the causal virus of mosaic disease in soybean putkong was cowpea mosaic virus.

• The Plant Pathology Journal
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• v.39 no.2
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• pp.181-190
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• 2023

The fungal pathogen Pseudocercospora fuligena, known to affect tomatoes in the tropics and subtropics, has been reported from temperate climates including the United States and Turkey in recent years. In this study, an isolate from fresh tomatoes and the disease it causes were characterized and infection mechanisms investigated. Macroscopically, both sides of tomato leaves show indistinct effuse patches but prolific production of fuliginous lesions is conspicuous on the abaxial side first but also on the adaxial side later on as infection progressed. Microscopically, fascicles of conidiophores (11-128 ㎛ × 3.5-9 ㎛) arising from stromata and conidia with up to 12 septations were observed. Molecular characterization of the isolate revealed high homology (99.8%) to other P. fuligena isolated from tomatoes in Turkey. Out of the 10 media tested, P. fuligena grew significantly well and sporulated better on unsealed tomato oatmeal agar and carrot leaf decoction agar, both supplemented with CaCO₃. Direct transfer of conidia from profusely sporulating lesions was the easiest and quickest method of isolation for in-vitro studies. Light and scanning electron microscopy on cleared and intact tomato leaves further confirmed stomatal penetration and egress as well as prevalence of primary and secondary infection hyphae. In situ, blocked stomatal aperture areas of 154, 401, and 2,043 ㎛² were recorded at 7, 12, and 17 days after inoculation, respectively. With the recent expanded horizon of the pathosystem and its consequential impact, such studies will be useful for a proper diagnosis, identification and management of the disease on tomato worldwide.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1246-1251
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• 2004

To investigate the effects of plant extracts on the protection against liver damage by $CCl_4$ in rat, two kinds of experiment were performed, firstly by the primary hepatocyte culture and secondly by the animal feeding. The primary hepatocyte culture with the extracts of pine leaf, soybean sprout and mugwort showed significantly low activities (p<0.01∼0.05) of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), indicating an excellent protective effect against liver damage by $CCl_4$. In the second experiment, the microsomal malondialdehyde (MDA) contents of the above same groups were also significantly lower (p<0.01) than the $CCl_4$-treated group without plant extracts, but shiitake showed less effect. Among four kinds of plant extracts, extracts of pine leaf and mugwort showed also much higher activities of the microsomal cytochrome P-450 in comparison to soybean sprout and shiitake. In the test of xanthine oxidase (XOD) activity, all of three groups except shiitake showed significantly low activities (p<0.01). These consistent results in vitro and in vivo suggest that the extracts of pine leaf, soybean sprout and mugwort may have strong protective effects against liver damage induced by the potential toxicants such as $CCl_4$.