• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.194-203
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• 2022

Cultivation of tomatoes in Korea grown in soil covers 89% of the total area for tomato cultivation. Tomatoes grown in soil often encounter various environment stresses including not only salt stress and soil-borne diseases but also cold stress in the winter season. This study was conducted to comparatively analyze the performance of rootstocks with cold stress by measuring the growth, yield, and photosynthetic efficiency in tomatoes grown in soil. The rootstocks were used 'Powerguard', 'IT173773', and '20LM' for the domestic rootstock cultivars and 'B-blocking' for a control cultivar. The tomato cultivar 'Red250' was used as the scion and the non-grafted tomatoes. Stem diameter, flowering position, leaf length, and leaf width were investigated for the growth parameters. The stem diameter of the non-grafted tomatoes decreased by 15% compared to the grafted tomatoes at 80 days after transplanting when exposed to low temperatures of 9-14℃ for 14 days. The leaf length and width of the non-grafted tomatoes were the lowest with 42.4 cm and 41.8 cm at 80 days after transplanting. The total yield per plant was the highest in tomato plants grafted on 'Powerguard' with 1,615 g and lowest in non-grafted tomatoes with 1,299 g. As the result of measuring the chlorophyll fluorescence parameters, PI_ABS and DI₀/RC, which mean the performance index and dissipated energy flux, 'Powerguard' was the highest with 3.73 in PI_ABS and the lowest with 0.34 in DI₀/RC, whereas non-grafted tomatoes was the lowest with 2.62 in PI_ABS and the highest with 0.41 in DI₀/RC at 80 days after transplanting. The stem diameter has positive correlation with PI_ABS, while it has negative correlation with DI₀/RC. The results indicate that can be analyzed by chlorophyll fluorescence parameters can be used for analyzing the differences in the growth of tomato plants grafted on different rootstocks when exposed to cold stress.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.243-250
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• 2018

BACKGROUND: Recently, the use of $^{131}I$ for diagnosis and treatment of thyroid cancer has been increasing, and the radionuclide is continuously released into aquatic ecosystem. This study was carried out to investigate the $^{131}I$ concentrations in mainstreams, tributaries, and sewage wastewater treatment plants (SWTPs) of the Yeongsan River Basin and to identify their origins from the assessment of behaviors in the rivers. METHODS AND RESULTS: The water samples were collected from 19 sites including mainstreams (13), tributaries (4) and SWTPs (2). The $^{131}I$ concentration was measured using a gamma-ray spectrometry with a HPGe detector. The $^{131}I$ in SWTPs was detected mostly in the discharged effluent at the sampling sites. However, from the surface water of the rivers, $^{131}I$ was found only at two sites from each sampling period of the first (MS4 and MS10) and the second half (MS4 and MS7) of the year 2017. The concentrations of $^{131}I$ in the effluent discharged from SWTPs were in the range of 0.0870 to 3.87 Bq/L for SWTP1, and $^{131}I$ in the river revealed that it was not detected in the upper streams of the mainstreams and tributaries, while continuous detection was found in the SWTPs and downstream sites affected by the effluent. However, the concentration of $^{131}I$ decreased downstream, eventually becoming undetectable. Such behavior was closely related to the behavior found in the SWTPs. CONCLUSION: These results indicated that medically-derived $^{131}I$ was discharged to the river via sewage effluent at the SWTPs. It is necessary to evaluate the influence of aquatic ecosystems through continuous monitoring in the future.