• Journal of Ecology and Environment
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• v.35 no.3
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• pp.213-225
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• 2012

Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.6
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• pp.165-177
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• 2023

Field surveys were conducted at a total of 50 locations targeting naturalized plants on Ulleung-do. A total of 109 taxa were identified, including the list of naturalized plants in the preceding literature. The naturalized plants of Ulleung-do had a high proportion of Asteraceae, which appeared frequently in the habitat of the ruderal type. There were no naturalized plants that settled only on Ulleung-do, and all naturalized plants found on Ulleung-do first settled on the Korean Peninsula. This was proved by the high rates of epecophyten (90.8%) and the introduction period 2nd (70.6%). On the other hand, among ecosystem-disturbing species that have a great influence in the inland of the Korean Peninsula, Hypochaeris radicata and Rumex acetosella appeared in a limited area in Ulleung-do. On the other hand, Lapsana communis appeared in high density along the forest edge, requiring management of naturalized plants different from those in the Korean Peninsula. Naturalized plants on Ulleung-do showed a rapid increase in the 1990s after increased academic research, coastal road development, and other development projects. This highlights the necessity for continuous research on the pattern of naturalized plant occurrence after the completion of the Ulleung Airport, which is currently under construction.

• Korean Journal of Plant Taxonomy
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• v.50 no.3
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• pp.351-355
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• 2020

Argyreia gyrobracteata Traiperm & Chitchak (Convolvulaceae) is newly recorded in Vietnam. It is similar to A. mekongensis Gagnep & Courch in having a white campanulate corolla but differs from that species by having whitish surface of the abaxial leaf, narrowly lanceolate or linear-oblong, curly, rolled up the bract with a longer length of the petiole and a shorter pedicel. It was previously known only in Thailand, but was recently found in Lam Dong Province, Vietnam, for the first time. The present study provides a detailed description, colorful photos and the distribution of the species. Furthermore, a comparison of the diagnostic characters between this species and a related species in Vietnam, A. mekongensis Gagnep & Courch, is provided.

• Journal of Ecology and Environment
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• v.48 no.3
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• pp.277-284
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• 2024

Background: Newly introduced transgenic plants can outcompete native species in natural ecosystems, threatening the biodiversity of a country. This study ascertained the weediness potential of plants according to the seed amount under the assumption that transgenic seeds were unintentionally spilled. Using sunflowers as the study system, 0, 50, 100, and 150 seeds were sown in 1 m × 1 m and 2 m × 2 m plots, and seed germination, survival, flowering, and competition between the surviving and wild plants were investigated. Results: There was no significant difference in the germination rate of sunflowers depending on the cultivar, but differences were observed depending on the sowing density and plot size. As the number of seeds sown increased, the flowering and seed maturation of sprouted plants occurred earlier; the plant height and flower length of the surviving plants decreased. In addition, as the number of seeds increased, not only did the early importance of sunflowers increase, but the period of dominance over weeds also improved. Conclusions: These results suggest that the weediness potential of sunflowers varies with the number of seeds at the time of release, which may affect germination and growth, and compete with weeds in transgenic plants.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.253-257
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• 2021

This work demonstrates the use of baromembrane method based on reverse osmosis (RO) process. The method is realized on mobile complex, which allows to concentrate and determine ultra-low activity of radionuclides in water cooling ponds of Russian nuclear fuel cycle enterprises. The existence level of radionuclide background creates difficult conditions for identification the contribution of liquid discharges enterprise, as standard monitoring methods have a very high detection level for radionuclides. Traditional methods for determining the background radionuclides concentrations require the selection of at least 500 liters (l) of water, followed by their evaporation to form a dry residue. This procedure with RO membranes requires at least 5 days. It is possible to reduce the time and energy spent on evaporation of hundreds of water liters by pre-concentrating radionuclides in a smaller sample volume with baromembrane method. This approach allows preliminary concentration of water samples from 500 l volume till 20 l volume during several hours. This approach is universal for the concentration of dissolved salts of any heavy metals, other organic compounds and allows the preparation of water countable samples in much shorter time compared to the traditional evaporation method.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.273-275
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• 2022

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.10a
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• pp.60-62
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• 2010

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2009.10a
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• pp.35-39
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• 2009

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2009.04a
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• pp.84-86
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• 2009

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2000.04a
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• pp.51-54
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• 2000