• Korean Journal of Weed Science
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• v.5 no.1
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• pp.50-55
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• 1985

Effects of weed removal time on maize growth and yield were evaluated in the fields dominated with Poligonum spp., Chenopodium album, Echinochloa crusgalli and Digitaria adsendens from 1982 to 1983 in Suweon. Weed removal treatments were as follows: (a) kept weedfree all season, (b) weeded at 10 day intervals after maize emergence but stopped weeding at 3,5,7,9 leaf stages, (c) weeds initially removed at 3,5,7 and 9 leaf stages and the plots then kept weed free, (d) weeds left all season. Maize kept weed free from maize emergence to 7 leaf stages showed no grain yield reduction due to competition from weeds emerging later, but weeding from emergence to 3 and 5 leaf stages reduced grain yield 46 and 44%, respectively, in 1982 and 29 and 18%, respectively, in 1983. Weeding at 3 leaf stage and thereafter did not influence grain yield but initial weedings at 5, 7 and 9 leaf stages reduced grain yield 10, 36, and 67%, respectively, in 1982 and 14,18, and 21%, respectively, in 1983. Responses of maize to weeding time in the dry matter yields were same as in the grain yields.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.237-241
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• 1997

Including the check five tiller removal treatments; early tillering stages and active tillering stages, tasseling dates and flowering dates, were conducted for increasing the marketability of waxy maize hybrid with tillers. From resulting the experiments, the effects of ear size on the removal of tillers were largely appeared at treatment of early tillering stages, and next active tillering stages, tasseling dates and flowering dates. In analysis of variation ear length was shown the significance at 5% among treatments and ear diameter was shown significantly at 1%. Correlationships among components related to yield were positively shown between ear length and leaf width, ear diameter and leaf length. while was negativly shown between ear length and ear width.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.2
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• pp.126-136
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• 2008

Tobacco plants grown in pots by sand culture for 70 days after transplanting were used to evaluate the sensing distance and measurement efficiency of ground-based remote sensors. The leaf distribution of tobacco plant and sensing distance from the sensors to the target leaves were controlled by two removal methods of leaves, top-down and bottom-up removal. In the case of top-down removal, the canopy reflectance was measured by the sensor located at a fixed position having an optimum distance from the detector to the uppermost leaf of tobacco every time that the higher leaves were one at a time. The measurement of bottom-up removal, a the other hand, was conducted in the same manner as that of the top-down removal except that the lower leaves were removed one by one. Canopy reflectance measurements were made with hand held spectral sensors including the active sensors such as $GreenSeeker^{TM}$ red and green, $Crop\;Circle\;ACS-210^{TM}$ red and amber, the passive sensors of $Crop\:Circle^{TM}$, and spectroradiometer $SD2000^{TM}$. The reflectance indices by all sensors were generally affected by the upper canopy condition rather than lower canopy condition of tobacco regardless of sensor type, passive or active. The reflectance measurement by $GreenSeeker^{TM}$ was affected sensitively at measurement distance longer than 120 cm, the upper limit of effective sensing distance, beyond which measurement errors are appreciable. In case of the passive sensors that has no upper limit of effective distance and $Crop\;Circle^{TM}(ACS210)$ that has the upper limit of effective sensing distance specified with 213 cm, longer than that of estimated distance, the measurement efficiency affected by the sensing distance showed no difference. This result suggests that it is necessary to use the sensor specified optimum distance. The result revealed that active sensors are more superior than their passive counterparts in establishing between the relative ratio of reflectance index and the dry weight of tobacco treated by top-down removal, and in the evaluation of biomass. $The\;Crop\;Circle\;ACS-210^{TM}$ red was proved to have the highest efficiency of measurement, followed by $Crop\;Circle^{TM}(ACS210)$ amber and $GreenSeeker^{TM}$ red, $Crop\;Circle^{TM}$ passive, $GreenSeeker^{TM}$ green, and spectroradiometer, in descending order.

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.26-35
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• 2019

Purpose: The aim of this study was to estimate the antioxidant activities of 50%, 70%, and 100% ethanol extracts of Lycium barbarum leaf and chlorophyll removal extract. Methods: The antioxidant activities were estimated by measuring total polyphenol content and by assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfate) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). In addition, reactive oxygen species (ROS) production, DNA fragmentation, and antioxidant enzyme (superoxide dismutase and catalase) activities of the extracts were measured in hydrogen peroxide ($H_2O_2$)-stressed HepG2 cells. Results: The total polyphenol content, DPPH and ABTS radical scavenging activities, and FRAP value of the extracts increased in an ethanol concentration-dependent manner. The antioxidant activities of the chlorophyll-removal extracts were much higher than those of the chlorophyll-containing extracts. Cytotoxicity was not observed in HepG2 cells with extracts up to $1,000{\mu}g/mL$. All extracts inhibited ROS production in a concentration-dependent manner from $31.3{\mu}g/mL$ and inhibited DNA damage at $250{\mu}g/mL$. The SOD and catalase activities of cell lines treated with the extracts and $H_2O_2$ were similar to those of normal cells, indicating a strong protective effect. Conclusion: Lycium barbarum leaf extracts had high antioxidant activities and protected $H_2O_2$-stressed HepG2 cells. Since the chlorophyll-removal extract exhibited higher antioxidant activities than the chlorophyll-containing ones and the cytoprotective effect was similar, chlorophyll removal extract of Lycium barbarum leaf could be developed as ingredients of functional food and cosmetics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.216-222
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• 1994

Experiments were conducted in the research field of the former Wheat and Barley Research with three barley cultivars, Olbori, kangbori and Suwon 18, which show different growth characteristics. Relationships between the degree of grain filling and the functions of photosynthetic organs in grain growth post-anthesis were investigated by removal treatment of awns and leaves, Stems and leaf sheath contributed to final grain weight invariably with cultivars by 79.2∼81.4%. while the contribution rate of awns and leaf blades varied by different cultivars, Awns contributed by 11.6∼13.8% in 'Olbori' and 'Kangbori', and 5.4% in 'Suwon 18', Contribution of leaf blades was 15.4% for 'Suwon 18', and 4.8∼8.1% for other cultivars, Of leaf blades upper ones showed a higher contribution rate, Early-maturing cultivars which maintain leaf greenness to the late phase of grain growth or awned cultivars were considered advantageous in grain filling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.121-127
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• 1993

The barley plant for whole crop forage is advantageous to have traits with higher photosynthetic rate, biomass, lodging resistance, and awnless spikes. The objective of this study is to investigate performance of near-isogenic line pairs for the awned and awnless in the field, and to observe the variations in photosynthetic rate, yield and their related traits under removal of flag leaf and awns. Grain yield was 6% higher, but biomass and photosynthetic rate were 6～16% and 6% lower in the awned line than those in the awnless grown in the field ,respectively. Defoliation of flag leaf resulted in approximately 3～4%, and 5～6% decreases in 1,000 kernels and grain weights, respectively. Deawning at the heading stage of the long awned line decreased 1,000 kernels and grain weights by 7% and 15%, respectively, The removal of both assimilative tissues caused 14 and 21% decrements in 1,000 kernels and grain weights. Apparent photosynthetic rate of leaf blade in awnless line was 6.1 -9. 7 $CO_2$$_2$ ${\mu}$mole $m^{-2}$ $s{-1}$, much higher than that in awned line. The relative rates in the second and third leaves were about 93% and 55～63%, respectively as compared with that in the flag leaf. The results of the experiments suggest that the awnless line selected for whole crop forage is a potential plant type with higher photosynthetic rate, leaf area and greater biomass.

• Journal of Photoscience
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• v.9 no.2
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• pp.448-450
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• 2002

DNA samples extracted from Japanese cypress leaf tissues contain isopropyl alcohol-precipitable, high molecular weight compounds, which interfere ELISA for cyclobutane pyrimidine dimers (CPD). Removal of the compounds is achieved by DEAE ion-exchange column chromatography and improves the ELISA responses of the DNA. When extracting DNA repeatedly from the same leaf tissues, the DNA samples show CPD responses which increase with the order in sequential extraction, and hence for a reliable detennination of DNA lesion a thorough extraction of DNA is required. Clearing these two problems it was demonstrated that CPD level was slightly higher in the leaves of trees growing under full sunlight than in those growing under UBV -cut sunlight.

• Korean Journal of Pharmacognosy
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• v.22 no.4
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• pp.249-251
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• 1991

The cytotoxic and antibacterial activities of the leaf, the stem and the seed extracts of Luffa cylindrica were evaluated against L1210 cells and Streptococcus mutans OMZ176, respectively. Among hexane, ether, butanol and water fractions, the ether fraction demonstrated the most potent cytotoxic activity, and the $ED_{50}$ values of the ether extract from the leaf, the stem and the seed were 3.5, 3.7 and $13.7{\mu}g/ml$, respectively. Meanwhile, the other fractions showed negligible effect. Separately, it was found that the antibacterial activity of the respective fraction from three parts was insignificant.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.461-467
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• 2006

The growth pattern and the seasonal changes in nutrient contents of Humulus japonicus were investigated. Stem length of H. japonicus reached the maximum from 240 to 260 Julian date and the median value was found at 255 Julian date. The maximum leaf area was observed from 235 to 248 Julian date and the median value was at 240 Julian date. The maximum growth rate of the stem length ranged from 205 to 227 Julian date. The leaf area showed the maximum growth rate from 196 to 214 Julian date. The median date in the growth rate of the stem length and leaf area was 212 and 205 Julian date, respectively. The growth rate of H. japonicus was related to rainy season and precipitation. Phosphorus and sodium contents of H. japonicus were correlated with maximum potential rate of relative growth. Although stem biomass of H. japonicus was $ 1.5{\sim}3.5$ times larger than that of leaf, N content of the leaf ($4.48{\sim}5.27%$) was about 2 times higher than that of the stem ($2.00{\sim}3.62%$). High content of N might be responsible for the high growth rate of H. japonicus in summer. This result provides valuable information for appropriate timing for the removal of H. japonicus.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.393-401
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• 2017

The nitrate ($NO_3{^-}$) accumulation of hydroponically grown leafy vegetables may increase in the condition of a closed-type plant production system with low light intensity due to low activity of enzymes involved in nitrogen assimilation and the use of $NO_3-N$ as major nitrogen source. The objective of this study is to investigate the effects of light intensities, nutrient solution compositions and the time of nutrient solution removal before harvest on nitrate contents of hydroponically-grown lettuces in a closed plant production system. The reduction of nitrate contents in leafy lettuces 'Cheongchima' was higher in the treatments of 'TW' (nutrient solution removal) and '$(NH_4)_2CO_3$' (use of ammonium carbonate as nitrogen source) than those in other treatments, which significantly lowered fresh weight and leaf area of the plants. In the light intensity of $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, the nitrate content was effectively reduced without causing any growth retardation, by substitution of the nutrient solution composition that $NO_3-N$ was removed ('$NO_3-N$ removal' treatment) or the half strength of standard nutrient solution was applied ('1/2 S' treatment), for 7days before harvest. The effects of light intensity and the time of nutrient solution removal before harvest on growth and nitrate contents in leafy lettuces were investigated. The nitrate contents in leaves under the light condition of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ before nutrient solution removal were lower than those of 100 or $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The removal of nutrient solution for 7 days before harvest quickly reduced the amount of nitrates in leaves in all the light intensities with a greater degree under the $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ of light condition, while the 7 days-removal with both 200 and $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ of light conditions caused decrease in 16~31% of leaf area and 20~35% of fresh weight, compared to the 3 days-removal treatment. The nitrate contents were greatly reduced from 3,018 to 1,035 in $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and 2,021 to 480 ppm in the light condition of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, with the nutrient solution removal for 3 days before harvest, without causing any deterioration in growth and product quality. The vitamin C contents in leaves were higher in the treatment of nutrient solution removal for both 3 and 5 days before harvest with the light condition of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ than those in the light condition of 100 or $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$.