• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.205-213
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• 2018

Development and validation of crop models often require measurements of biomass for the crop of interest. Considerable efforts would be needed to obtain a reasonable amount of biomass data because the destructive sampling of a given crop is usually used. The Kinect sensor, which has a combination of image and depth sensors, can be used for estimating crop biomass without using destructive sampling approach. This approach could provide more data sets for model development and validation. The objective of this study was to examine the applicability of the Kinect sensor for estimation of chinese cabbage fresh weight. The fresh weight of five chinese cabbage was measured and compared with estimates using the Kinect sensor. The estimates were obtained by scanning individual chinese cabbage to create point cloud, removing noise, and building a three dimensional model with a set of free software. It was found that the 3D model created using the Kinect sensor explained about 98.7% of variation in fresh weight of chinese cabbage. Furthermore, the correlation coefficient between estimates and measurements were highly significant, which suggested that the Kinect sensor would be applicable to estimation of fresh weight for chinese cabbage. Our results demonstrated that a depth sensor allows for a non-destructive sampling approach, which enables to collect observation data for crop fresh weight over time. This would help development and validation of a crop model using a large number of reliable data sets, which merits further studies on application of various depth sensors to crop dry weight measurements.

• Plant Biotechnology Reports
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• v.4 no.2
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• pp.109-116
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• 2010

Morinda citrifolia adventitious roots were cultured in shake flasks using Murashige and Skoog medium with different types and concentrations of auxin and cytokinin. Root (fresh weight and dry weight) accumulation was enhanced at 5 $mg\;l^{-1}$ indole butyric acid (IBA) and at 7 and 9 $mg\;l^{-1}$ naphthalene acetic acid (NAA). On the other hand, 9 $mg\;l^{-1}$ NAA decreased the anthraquinone, phenolic and flavonoid contents more severely than 9 $mg\;l^{-1}$ IBA. When adventitious roots were treated with kinetin (0.1, 0.3 and 0.5 $mg\;l^{-1}$) and thidiazuron (TDZ; 0.1, 0.3 and 0.5 $mg\;l^{-1}$) in combination with 5 $mg\;l^{-1}$ IBA, fresh weight and dry weight decreased but secondary metabolite content increased. The secondary metabolite content (including 1,1-diphenyl-2-picrylhydrazyl activity) increased more in TDZ-treated than in kinetin-treated roots. Antioxidative enzymes such as catalase (CAT) and guaiacol peroxidase (G-POD), which play important roles in plant defense, also increased. A strong decrease in ascorbate peroxidase activity resulted in a high accumulation of hydrogen peroxide. This indicates that adventitious roots can grow under stress conditions with induced CAT and G-POD activities and higher accumulations of secondary metabolites. These results suggest that 5 $mg\;l^{-1}$ IBA supplementation is useful for growth and secondary metabolite production in adventitious roots of M. citrifolia.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.55-65
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• 2014

Radar remote sensing is appropriate for rice monitoring because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. And we applied the relationships to crop monitoring of paddy rice in North Korea. As a result, plant height and Leaf Area Index (LAI) increased until Day Of Year (DOY) 234 and then decreased, while fresh weight and dry weight increased until DOY 253. Correlation coefficients revealed that Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients were correlated highly with plant height (r=0.95), fresh weight (r=0.92), vegetation water content (r=0.91), LAI (r=0.90), and dry weight (r=0.89). Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients. Concerning the evaluation for the applicability of the LAI distribution from RADARSAT-2, the LAI statistic was evaluated in comparison with LAI distribution from RapidEye image. And LAI distributions in Pyongyang were presented to show spatial variability for unaccessible areas.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.495-502
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• 2016

Italian Ryegrass (IRG), which is known as high yielding and the highest quality winter annual forage crop, is grown in mid-south area in Korea. The objective of this study was to evaluate the use of unmanned aerial vehicle (UAV) for the monitoring IRG growth. Unmanned aerial vehicle imagery obtained from middle March to late May in Nonsan, Chungcheongnam-do. Unmanned aerial vehicle imagery corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). We analyzed the relationships between $NDVI_{UAV}$ of IRG and biophysical measurements such as plant height, fresh weight, and dry weight over an entire IRG growth period. The similar trend between $NDVI_{UAV}$ and growth parameters was shown. Correlation analysis between $NDVI_{UAV}$ and IRG growth parameters revealed that $NDVI_{UAV}$ was highly correlated with fresh weight (r=0.988), plant height (r=0.925), and dry weight (r=0.853). According to the relationship among growth parameters and $NDVI_{UAV}$, the temporal variation of $NDVI_{UAV}$ was significant to interpret IRG growth. Four different regression models, such as (1) Linear regression function, (2) Linear regression through the origin, (3) Power function, and (4) Logistic function were developed to evaluate the relationship between temporal $NDVI_{UAV}$ and measured IRG growth parameters. The power function provided higher accurate results to predict growth parameters than linear or logistic functions using coefficient of determination. The spatial distribution map of IRG growth was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when $NDVI_{UAV}$ was applied to power function. From these results, $NDVI_{UAV}$ can be used as a new tool for monitoring IRG growth.

• Korean Journal of Medicinal Crop Science
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• v.22 no.5
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• pp.384-390
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• 2014

This study was carried out in order to investigate the early growth and root development characteristics of Peucedanum japonicum container seedlings. The experiment was performed by containers (128 and 200 cavities containers) and shading levels (0%, 35%, 50% and 75% shading). Germination rate of P. japonicum seeds was getting higher in the lower shading level and the highest in the full sunlight (71.9%). Plant height was the highest under 50% shading of all containers. Fresh weight and dry weight of the shoot (leaves + stem) were the highest under 50% shading of all containers, too. Meanwhile, fresh weight and dry weight of the root per plant were the highest under the full sunlight of 128 cavities container such as 0.34 g and 0.03 g, respectively. Total root length, root project area and root surface area were higher under the full sunlight of 128 cavities container such as 234.5 cm, $6.6cm^2$ and $20.8cm^2$, respectively and the next higher was under 35% shading such as 201.7 cm, $5.9cm^2$ and $18.4cm^2$, respectively. A case of root volume was the highest with $0.15cm^3$ under the full sunlight. As a result of the surveying the whole experiment, it is concluded that the shoot and root of P. japonicum seedling grow nicely by maintaining 35% shading.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.424-430
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• 2018

This study was carried out to estimate growth characteristics of hot pepper and to develop predicted models for the production yield based on the growth parameters and climatic elements. Sigmoid regressions for the prediction of growth parameters in terms of fresh and dry weight, plant height, and leaf area were designed with growing degree days (GDD). The biomass and leaf expansion of hot pepper plants were rapidly increased when 1,000 and 941 GDD. The relative growth rate (RGR) of hot pepper based on dry weight was formulated by Gaussian's equation RGR $(dry\;weight)=0.0562+0.0004{\times}DAT-0.00000557{\times}DAT^2$ and the yields of fresh and dry hot pepper at the 112 days after transplanting were estimated 1,387 and 291 kg/10a, respectively. Results indicated that the growth and yield of hot pepper were predicted by potential growth model under plastic tunnel cultivation. Thus, those models need to calibration and validation to estimate the efficacy of prediction yield in hot pepper using supplement a predicting model, which was based on the parameters and climatic elements.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.37-41
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• 2011

This experiment was carried out to find an optimum shading level for the growth of root and shoot, and to find the effect of shading level after August on the induction and growth of inflorescence of Phalaenopsis hybrid. The shading levels were 50%, 60%, 70%, 80% and 90% of natural light($1200{\mu}molm^{-2}s^{-1})$. The $CO_2$ uptake, transpiration rate, carbohydrate content, fresh weight and dry weight of Phalaenopsis hybrid were higher at 50-60% level than the others. But, it was diminished when the shading level was increased from 70% to 90%. Inflorescence length, the number of inflorescence and flower per plant all increased under 50-60% shading level and the day needed for the flowering after treatment decreased. Especially, the induction of inflorescence was depressed and flowering is not occurred under 90% during experiment period. These results suggest that the optimal shading level for the growth of Phalaenopsis including inflorescence was founded to be 50-60% in the season of light intensity and amount of sunshine decrease after august.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.3
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• pp.153-157
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• 2019

Salicylic acid (SA) is an essential plant growth regulator that functions as a signaling molecule in plants. The purpose of this study was to clarify how the exogenous application of SA counteracts aluminum stress-induced growth and biomass yield reduction in alfalfa exposed to aluminum (Al) stress. Two-week-old alfalfa seedlings were exposed to a combination of $AlCl_3$ ($0{\mu}M$, $50{\mu}M$ and $100{\mu}M$, respectively) and SA (0.1 mM) for 72 hours. We observed, Al stress-induced plant growth inhibition and forage yield reduction are Al stress-dependent manner. A significant reduction of plant height (42.0-52.9%), leaf relative water content (13.0-21.4%), root length (35.4-48.7%), shoot fresh weight (31.2-25.9%), root fresh weight (15.4-23.3%), shoot dry weight (12.7-22.2%), roots dry weight (47.3-53.5%), were observed in alfalfa. In contrast, SA alleviated the Al-stress and enhanced growth and biomass yield in alfalfa. This study provides useful information concerning the role of SA that counteracts aluminum stress-induced growth and yield reduction in alfalfa.

• Korean Journal of Medicinal Crop Science
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• v.22 no.2
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• pp.154-159
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• 2014

This study was carried out in order to investigate the early growth and root development characteristics of Atractylodes japonica container seedling. Experiment was performed by light intensity (100%, 60%, 25% and 10% of full sunlight). Height was surveyed well under 25% of full sunlight (overall 11.013.0%). Root collar diameter was the highest in the full sunlight (7.52 mm). It was the highest fresh weight (1.52 g, 0.92 g, 0.90 g and 3.34 g) under 25% of full sunlight, root dry weight was getting higher in the higher light level and the highest in the full sunlight (0.13 g). Total root length, root project area, root surface area and root volume were the highest under 25% of full sunlight (434.7 cm, $17.4cm^2$, $54.7cm^2$, $0.55cm^3$, respectively) and the lowest under 10% of full sunlight. As a result of surveying the whole experiment, A. japonica is judged nicely by maintaining 25% of full sunlight, excepting 10% of full sunlight. And light levels during the early growth are overly important to improve early growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.350-356
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• 1981

An experiment was carried out to investigate the effect of the vinyl pot size and number of plants per pot on the seedling growth. Dry weight per plant, coefficient of variance and dry weight/fresh weight ratio increased as pot size increased, but competitive index, unit productivity and top/root ratio decreased. Dry , weight per plant decreased with increase in number of plants per pot, but coefficient of variability, competitive index and unit productivity increased. Dry weight per plant of the check plot (1 seedling/3.5cm $\times$ 3.5cm pot) showed little difference between 3 plants/4cm x 4cm pot and 5 plants/5cm x 5cm pot. Temporary transplanting of five plants per 5cm $\times$ 5cm pot saved seedbed area and seedbed materials by 60.9% and labor of transplanting by 36.3% as compared with check plot.