• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.218-224
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• 2019

This study was conducted to compare the effect of salicylic acid (SA), an ethylene biosynthesis inhibitor, and the 1-methylcyclopropene (1-MCP) fumigation, to prevent fruit quality deterioration and physiological disorders during the shelf-life of Korea's leading export grape variety 'Campbell Early'. The berries treated with SA after 1-MCP fumigation (1-MCP+SA) showed a higher firmness value and titratable acidity than single treatment of SA or 1-MCP. The rate of shattered berry was high as 41.7% for 100ppm ethephon spray, 40.8% for $25{\mu}M$ SA, and 38.2% for 1,000ppb 1-MCP, but showing only 18.7% when the SA was applied after 1-MCP fumigation. The ratio of short brushes less than 1mm was largest at 74.3% for ethephon treatment, while 1-MCP+SA treatment was found to have the longest brush length among all treatments, with a 2-4mm ratio of 22.8% and a 4-6mm ratio of 27.9%. The weight of rachis was found to be the lowest at 2.3g in the ethephon treatment, and the reduction of rachis weight loss per cluster by 1-MCP+SA treatment was evident. In addition, 1-MCP+SA treatment were effective in mitigating stem browning and berry decay during the 16-day storage period at $19^{\circ}C$ in this cultivar, so it is believed that they can be used as a practical post-harvest treatment in grape exportation.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.384-392
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• 2022

The objective of this study was to estimated nitrogen content and chlorophyll using RGB, Hyperspectral sensors to diagnose of nitrogen nutrition in apple tree leaves. Spectral data were acquired through image processing after shooting with high resolution RGB and hyperspectral sensor for two-year-old 'Hongro/M.9' apple. Growth data measured chlorophyll and leaf nitrogen content (LNC) immediately after shooting. The growth model was developed by using regression analysis (simple, multi, partial least squared) with growth data (chlorophyll, LNC) and spectral data (SPAD meter, color vegetation index, wavelength). As a result, chlorophyll and LNC showed a statistically significant difference according to nitrogen fertilizer level regardless of date. Leaf color became pale as the nutrients in the leaf were transferred to the fruit as over time. RGB sensor showed a statistically significant difference at the red wavelength regardless of the date. Also hyperspectral sensor showed a spectral difference depend on nitrogen fertilizer level for non-visible wavelength than visible wavelength at June 10th and July 14th. The estimation model performance of chlorophyll, LNC showed Partial least squared regression using hyperspectral data better than Simple and multiple linear regression using RGB data (Chlorophyll R²: 81%, LNC: 81%). The reason is that hyperspectral sensor has a narrow Full Half at Width Maximum (FWHM) and broad wavelength range (400-1,000 nm), so it is thought that the spectral analysis of crop was possible due to stress cause by nitrogen deficiency. In future study, it is thought that it will contribute to development of high quality and stable fruit production technology by diagnosis model of physiology and pest for all growth stage of tree using hyperspectral imagery.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.122-131
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• 2023

This study was aimed to determine the effects of grow media on the mineral contents of the leaves and growth characteristics of strawberry grown under aquaponics system in a plant factory. For aquaculture, 12 fish (Cyprinus carpio) (total weight, 2.0 kg) were raised in an aquaponics tank (W 0.7 m × L 1.5 m × H 0.45 m, 472.5 L) filled with 367.5 L of water at a density of 5.44 kg·m^-3 and total 34 of strawberry seedlings were transplanted in the pots filed with 200 g of orchid stone, hydroball or polyurethane sponge in the growing bed (W 0.7 m × L 1.5 m × H 0.22 m) laid out with holly acrylic sheet (140×60 mm, Ø80) on the top of the system. The pH and EC of the aquaponic solution was ranged from 7.6 to 4.9 and 0.24-0.91 dS·m^-1, respectively. The concentration of NO_3-N was about 28% lower than that of the hydroponic standard solution, and K, Fe and B were 10, 27 and 3.8 times lower, respectively; however, the mineral contents of strawberry leaves were in the appropriate ranges with lower contents in the leaves grown with sponge media. The organic content (OM), nitrogen (N), phosphorus (P), and potassium (K) of the sludge were 61.5, 5.72, 8.92, and 0.24%, respectively. The leaf area, leaf number, and dry and fresh weights of shoot at 81 DAT were significantly higher in the hydroball, and the average number of fruits per plant was significantly higher in both the orchid stone and hydroball. There was no significant difference in the fresh and dry weights of fruits. Integrated all the results suggest that the orchid stone and hydroball media are more effective to utilize nutrients in solid particles of aquaponic solution, compared to the polyurethane sponge.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.349-355
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• 2010

This experiment was conducted to establish the optimum nitrogen application level for oriental melon at Seong-ju Fruit Vegetable Experiment Station with a fertigation system. Four different levels of nitrogen fertigation were applied to oriental melon and growth of the plant was analyzed. Plant samples were collected 8 times and were analyzed by the standard methods. The first fertigation was applied at 10 days after transplanting for the oriental melon based on the growth rates of the plants. For oriental melon, 10 day interval fertigation and 8 time split application of fertilizer could be recommended. The amounts of N, P, and K fertilizer recommended by soil testing was 249-408-315 (kg $ha^{-1}$). Treatment levels were 0, 0.5, 1.0, and 1.5 times of soil testing nitrogen with P and K level fixed. The total nitrogen (T-N) content in dried leaf showed a tendency to increase until 30 days after transplanting, then decreased. T-N content increased with increasing nitrogen fertigation rates. T-N content in dried fruit decreased slightly during the whole growing season. Fresh weight and nitrogen uptake were increased with increasing nitrogen fertigation rates. Total yield and marketable yield, 44,550 kg $ha^{-1}$ and 42,880 kg $ha^{-1}$, were maximized at 0.5 times of soil test nitrogen. Ratio of marketable fruit, 95%, was the highest at 0.5 times of soil test nitrogen. The optimum level of nitrogen for fertigation system was 0.5 times soil test nitrogen judging from total yield, commodity yield and commodity fruit.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.236-242
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• 2012

This study was carried out to investigate the effect the water content in coir substrates as according to growth stage on the growth and yield of mini-paprika of three varieties 'E 499524' (red color), 'E 499526' (yellow colar) and 'E 499531' (orange colar) in summer hydroponics. Treatments of I, II and III were composed of 55-65-60, 50-60-55 and 45-55-50% in water contents of growth stages, respectively. Time domain reflectometry (TDR) sensors were used in a drip irrigation system. The early growth of mini-paprika was increased by high medium water content of treatment I in all of three varieties. Mean fruit weight was not affected by medium water content, but the fruit number per plant and yield were increased at high medium water content of treatment I. The Yield of treatment I was higher than that of treatment II and III in all of three varieties. The sugar content was increased by low medium water content of treatment in all of three varieties. The incidence of brown-stem fruit, blossom-end rot and sunburn was decreased with increasing water content of medium. Occurred in the low water content of medium. Mineral contents of fruits such as nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg) etc. were not affected in all of three varieties.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.5
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• pp.739-745
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• 2011

This study was performed to investigate the enrichment of resveratrol content in harvested grapes using the modulation of cell metabolism with ultra-violet (UV) irradiation. Resveratrol, a phytoalexin, is produced by stilbene synthase (STSY) from malonyl-CoA and ${\rho}$-coumaroyl-CoA. Its biosynthesis has been reported to be induced by UV and other environmental factors. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed that STSY Promoter 1 in grapes was very highly expressed by treatment with UV. Grapes were harvested and treated for post-harvest induction of STSY gene expression with UV, and then their resveratrol content was analyzed. UV treatment for 5 minutes provided the best condition for the induction of STSY gene expression. When harvested Gerbong and MBA grapes were treated with a prototype UV radiator, their resveratrol content was enriched upto 5 times compared with untreated grapes. These results suggest that a post-harvest UV treatment can be applied to enrich resveratrol content in grapes and add value to them.

• Research in Plant Disease
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• v.18 no.4
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• pp.354-360
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• 2012

This study tested the antifungal compound obtained from a medicinal plant, Dioscorea quinqueloba Thunb., in order to search the possibility of practical application of this product in agriculture through evaluating its activity using the citrus fruits. The extract of D. quinqueloba Thunb., which has the strongest antifungal activity, was selected as a candidate among 101 plant extracts. Based on this examination concerning antifungal activity of the product on Penicillium digitatum in vitro, it was confirmed its effect of mycelial growth inhibition showed over 87% at 0.5 mg/ml concentration. This natural product showed the stability of the substance, as it was not significantly influenced by pH, temperature, or ultraviolet radiation. While citrus fruits were stored at room temperature, P. digitatum was inoculated into them in order to prepare a similar environmental conditions with epidemic occurrence of the mold. As the result of our investigation, the disease preventive effects of the active antifungal substance evidenced a 100% at 0.5 mg/ml. When the phytotoxicity of the selected natural product on citrus at 2 mg/ml was assessed, we noted no toxic effects. Based on the superior preventive effects from this natural product extracted from the plant, it is presumed to be very useful in agricultural applications for the control of green mold, P. digitatum, which has been occurred often the biggest problem in the storage of citrus fruits.

• Journal of Life Science
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• v.30 no.3
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• pp.239-249
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• 2020

Persimmon flowers are fruit-bearing female, pollen-bearing male, or hermaphrodite, containing both a pistil and a stamen. Using prominent PCNA persimmons as male parents is very important for breeding programs, as the selection procedure for new cultivars bearing male flowers requires a long time and a large field in a traditional crossbreeding method. To improve breeding efficiency through early selection of male flower-bearing plants at the seedling stage, analysis was performed on 88 major cultivars whose gender expressions are known, using two male flower selection markers recommended by Akagi et al. The OGI locus marker and DISx-AF4S marker results showed that 83 and 72 cultivars, respectively, matched in terms of gender expression and marker analysis. For the OGI locus marker, 890 plants were selected from 2,509 seedlings obtained from crossbreeding with the mother plant "Migamjosang," which was the breeding cultivar. Comparing the gender expression of the flowers and the marker with 1,186 crossbred seedlings, excluding the unfertilized and dead plants, inconsistencies were found in 401 plants (33.8%). For the DISx-AF4S marker, 636 plants were selected from 889 seedlings obtained from 12 cross-combinations. The results of the sex expression and marker analysis were compared to 379 plants, excluding the unfertilized and dead plants, and inconsistencies were found in 247 plants (65.2%). These results indicate that the examined DISx-AF4S and OGI locus markers would not be suitable for utilization in the breeding field.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.320-326
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• 2017

This study investigated the water extracts of fallen pear (FPWE) on tyrosinase activity and melanogenesis. In the present study, we examined the effects of FPWE on mushroom tyrosinase activity in vitro, B16F10 melanoma cell tyrosinase activity, melanin contents, and expression of melanogenic enzyme proteins such as tyrosinase. An apparent down-regulatory effect on tyrosinase activity was observed when B16F10 cells were incubated with FPWE. Results of melanin assay using B16F10 cells treated with different concentrations (50, 125, and $250{\mu}g/mL$) of FPWE showed a dose-dependent decrease in melanin content. To determine whether or not FPWE indirectly affects tyrosinase activity, we assessed mushroom tyrosinase activity upon treatment with various concentrations (125, 250, 500, and $1,000{\mu}g/mL$) of FPWE. In addition, we investigated changes in the protein level of tyrosinase by using Western blotting. Tyrosinase and microphthalmia-associated transcription factor expression levels in B16F10 melanoma cells were reduced in a dose-dependent manner by FPWE. These results suggest that FPWE reduced melanin formation by inhibition of tyrosinase activity. Therefore, we suggest that FPWE could be used an effective whitening agent for skin.

• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.175-183
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• 2003

Fruit and vegetables are subjected to complex dynamic stresses in the transportation environment. During a long journey from the production area to markets, there is always some degree of vibration present. Vibration inputs are transmitted from the vehicle through the packaging to the fruit. Inside, these cause sustained bouncing of fruits against each other and container wall. These steady state vibration input may cause serious fruit injury, and this damage is particularly severe whenever the fruit inside the package is free to bounce, and is vibrated at its resonance frequency. The determination of the resonance frequencies of the fruit and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. Instrumentation and technologies are described for determining the vibration response characteristics of the fruits with frequency range 3 to 150 Hz. The computer program for controlling the vibration exciter and the function generator and for measuring the vibration response characteristics of the fruits was developed. The resonance frequency of the pear ranged from 64.5 to 72.2 Hz and the amplitude at resonance was between 1.78 and 2.21 G-rms. The resonance frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.