• Journal of Ecology and Environment
• /
• v.36 no.3
• /
• pp.167-172
• /
• 2013

A Two-year field experiment was carried out in 2009 and 2010 to evaluate the effects of different densities of wild oat and nitrogen (N) rates on oilseed rape yield and yield components. Experimental design was split plot with three replications. Increased nitrogen rates up to 150 kg N/ha caused an increase in oilseed rape grain yield in weed-free plots (4.26 t/ha; 1t = $10^3kg$), while even at the lowest density of wild oat (15 $plants/m^2$), increasing N fertilizer only up to 50 kg/ha led to a significant increase in grain yield. Wild oat growth was favored by high levels of N. Intraspecific competition reduced biomass, 100-seed weight and number of tillers of wild oat. Both lower N rate and intraspecific competition had negative effect on wild oat growth but the weed was still able to produce a considerable number of tillers and vigorous seeds. It showed that wild oat possess a notable adaptive plasticity and can allocate a greater proportion of its resource toward reproductive organs even under resource shortage conditions and, thus, it may increase the competitive ability of the weed over the crop.Our results suggest that effective weed management should be done to prevent wild oat seed production in crops preceding oilseed rape as well as to control the weed at early season in oilseed rape fields.

• Journal of Ecology and Environment
• /
• v.41 no.9
• /
• pp.246-255
• /
• 2017

Background: The aim of this study was to examine the resource allocation among the organs and the leaf morphology of Polygonatum humile. The data were collected from June 2014 to May 2015 in a natural P. humile stand of a temperate forest gap. Results: The dry weight of new rhizome ($R_0$) sharply decreased to the time of new shoot sprouting in next year and was constant for 2 ~ 3 years. However, dry weight of root on $R_0$ increased to the end of growth season and, thereafter, decreased slowly along the time elapsed. The correlation coefficients between the rhizome and the leaf sizes were 0.5 for the last year's rhizome ($R_1$) and 0.6 for $R_0$ and were significant at 0.1% level for $R_0$. The increase of one leaf a plant led to increase of the total leaf area, total leaf weight, and stem length. Moreover, the organ sizes' differences between two plants of the one leaf difference were almost significant at 1% level. In 11-leaf plant, the leaf length/width ratio and specific lea area increased to the second, relative leaf area to the fourth and relative leaf dry weight to the fifth, and thereafter, decreased to the last leaf. The differences in the values of these four parameters between two leaves on a stem were almost significant at 5% level. Conclusion: P. humile examined showed the close relationships between the last year's rhizome or this year's one and the shoot system (leaf and stem) sizes. The leaf number a shoot greatly influenced specific leaf area. P. humile's leaf might showed diverse morphology with leaf rank on a stem in a forest gap environment.

• Environmental and Resource Economics Review
• /
• v.28 no.4
• /
• pp.617-643
• /
• 2019

The Demilitarized Zone(DMZ) is a buffer zone set between the southern and northern limit lines established after the 1953 Armistice Agreement. It is an important natural environment conservation area where wild species of animals and plants live. On the other hand, the development pressure on the DMZ will increase when the inter-Korean economic cooperation is activated in the future. As a result, DMZ development should consider not only the economic cost-benefit aspects, but also how to assess and conserve the biodiversity of the DMZ, as well as the recovery costs and budget. This paper develope a sustainable DMZ management model under biodiversity uncertainly by using real option approach. The model is also designed to reflect the political risk and regional specificity of the DMZ. Through empirical analysis, I derive the biodiversity threshold (b^*) that can secure the DMZ investment economy under uncertainty. In addition, through the sensitivity analysis, I derive the factors influencing the biodiversity threshold, and suggest the policy implications for sustainable management of DMZ.

• Korean Journal of Medicinal Crop Science
• /
• v.17 no.1
• /
• pp.33-38
• /
• 2009

The full-length cDNA encoding Perilla frutescens limonene synthase (PFLS) (603 amino acids, GenBank accession no. D49368) was cloned. To elucidate the role of PFLS in gene regulation, we transiently transformed full-length PFLS into tobacco plants. PFLS mRNA was first detected in the intact leaves of the plants at 6 h, and the LS transcript level increased after 12 h in leaves treated with oxidative stress-related chemicals. The transient overexpression of PFLS resulted in increased transcription of NbPR1 and NbSIP in Nicotiana benthamiana leaves. Thus, our result confirmed that the infiltration of PFLS gene act as a transcriptional regulator of NbPR1 or NbSIP genes in the tobacco.

• Journal of Life Science
• /
• v.24 no.8
• /
• pp.903-909
• /
• 2014

Plants are an invaluable source of potential new anti-cancer drugs. Sasa quelpaertensis Nakai (Korean name, Jeju-Joritdae) is one of these plants with medical value, which is a bamboo grass widely distributed in Mt. Halla on Jeju Island, Korea. Here, we investigated the apoptotic effects of S. quelpaertensis leaf extracts in six human cancer cell lines (A549, MCF-7, HepG-2, Hela, HCT116 and A375). MTT assay signified the antiproliferative nature of S. quelpaertensis extracts against all tested cancer cells: S. quelpaertensis displayed slight cytotoxicity against A549, MCF-7 and HepG-2 cells, whereas it was exclusively cytotoxic to Hela, HCT116 and A375 cells. Apoptotic cells were evaluated using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). PI staining indicated increasing accumulation of Hela, HCT116 and A375 cells at sub-G1 phase. Further events like generation of nitric oxide ($NO^{\bullet}$) were accompanied in the S. quelpaertensis Nakai-induced apoptosis. Augmented $NO^{\bullet}$ generation resulted in the DNA fragmentation of Hela, HCT116 and A375 cells by treatment with S. quelpaertensis leaf extracts. These results suggest that S. quelpaertensis may be a potential natural resource for treating cancer cell. To identify the exact mechanisms of molecular mechanism of S. quelpaertensis induced apoptosis awaits further investigation.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.320-320
• /
• 2022

Coriander(Coriandrum sativum L.) belongs to the family Umbelliferae/Apiaceae. It is cultivated as a spice and medicinal herb around the world, including its leaves and seeds. Coriander leaves have soft and fragrant, so they can be used in cuisines such as China, Mexico, and, Southeast Asia. Coriander leaves contain a high amount of vitamin C, carotene, and multiple polyphenols. Coriander essential oils and extracts have various chemical components and are known to have antioxidant, antibacterial, and antifungal activities. This study was carried out for resource discovery, propagation, and DB construction of aromatic plants. In order to evaluate the genetic characteristics, 30 kinds of Coriander seeds were supplied from the Center for Genetic Resources. The evaluation of characteristics of the basal part leaf number, leaf shape, and plant height was investigated. Also, Essential oils extract from various parts of plants including the leaves, flowers, and steam isolated by simultaneous distillation extraction(SDE) apparatus. In the results, heights showed growing to 70 cm over and basal part leaf number 0 to7. The leaves are variable, they are measured according to leaves incisions, and most of the included incision. The qualitative analysis of EOs was performed using gas chromatography-mass spectrometry. EOs had various chemical compositions. Major compounds were trans-2-Decenal, linalool, decanal, 2-Dodecenal, 13-Tetradecanal, 2-Undecenal.

• Journal of Environmental Science International
• /
• v.18 no.1
• /
• pp.113-127
• /
• 2009

This study was designed to present a river model with an aim at restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhan river, a core life channel for the National Capital region. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. Communities of Juglans mandshurica, Cornus controversa and Fraxinus mandshurica constitute the main portion of flora at or around uppermost branch streams of the River Namhanis harbored mainly in and around small brooks 2. Typical terrestrial forest communities formed around the River Namhan are composed mainly of Larix leptolepis, Pinus rigida, planned forestation of Pinus koraiensis, Quercus acutissima, Quercus variabilis and Pinus densiflora. 3. The analysis into terrestrial environment of plant communities showed a high content of $P_2O_5$, typical communities found in the artificially disturbed land Finally, it seems also desirable to continue to make every exertion to explore the relationship between fluvial and terrestrial ecologies with a purport of building up a model of natural streams in urban area based on the surveyed factors for plant life, forest communities, soil and landscape and, moreover, on the forecasting for overall influences derived from the relation upon the ecosystem.

• Korean Journal of Environmental Agriculture
• /
• v.28 no.3
• /
• pp.301-309
• /
• 2009

The use of bioactive materials derived from microorganisms and plants has played a role in pest management in environmentally-friendly agriculture (EFA) system. In Korea, a number of agricultural agents for the control of insect pests have been registered officially as biopesticides and marketed widely. However, most of the biopesticides has a limitation in the resource availability of bioactive materials, which has been one of main problems related to the commercialization of agricultural agents. Plant materials and microbial metabolites are the best sources as starting components to commercialize natural-occurring agricultural agents for pest management. The lack of modernized system for the standardization and quality control of the starting materials, however, has also received as a main problem related to the commercialization of agricultural agents. Considered that EFA business has kept growing bigger and bigger with global economic status, the commercialization of agricultural agents is necessary to meet the required number of agricultural agents officially available in EFA. This study describes the status and future prospects of pest control agents in EFA. A number of main issues hindered in the commercialization of agricultural agents are discussed in order to present a promising approach to successful commercialization.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.7 no.1
• /
• pp.10-18
• /
• 2004

The urban ecosystem, unlike the natural ecosystem, has been affected by the urban environment, so the existences of normal creatures have been threatened and eventually the stability has declined to consist of those that have adapted to such. Therefore, by creating a list of such organisms, their number of variety can be found out and their ecological distinction can be understood. Because flora is known to be an ecological index reflecting region's effects of human and societal environments, weather, and climates, it is a useful method of finding out the ecological position and distinctiveness of that region. The study site is part of watershed at Yangjae Stream, Kahngnam-ku, Seoul. In this study, the difference of flora in each land use type are investigated by plant identification. The purpose of this study is to evaluate the city's plant surviving environment, and eventually to contribute to the restoration of urban green spaces by finding out the plants which are appropriate for the corresponding environment. After doing the study, it was found that the urban forest is the most stable urban ecosystem while the urban park is seriously disturbed, and ecologically unstable. The urban stream is also disturbed continuously.

• Natural Product Sciences
• /
• v.29 no.1
• /
• pp.1-9
• /
• 2023

This study assessed in vitro antioxidant activity (ABTS⁺ and DPPH) of Vitex rotundifolia seeds collected from two different regions in Korea (Jungjang City and Sindu City). Three extraction methods using ethanol, methanol, and water were prepared separately and subjected to quantification by reverse-phase high-performance liquid chromatography-photodiode array (HPLC-PDA) analysis as well as antioxidant testing. Among them, the water-based extract exhibited superior activity in the ABTS⁺ compared with the ethanol- and methanol-based extracts, while the DPPH assay analysis, revealed that the methanol-based extract had very low antioxidant activity. The concentrations of vanillic acid (1), luteolin (2), vitexicarpin (3), and artemetin (4) were quantified using HPLC-PDA analysis. Vanillic acid (1) was identified as the main antioxidant in V. rotundifolia seeds. Combining the antioxidant activity and quantitative analysis results, the water-based extract was considered to have the highest antioxidant activity. Furthermore, vanillic acid (1) was detected in the leaves and stems of V. rotundifolia plants from different regions, indicating that this species has the potential for use in future antioxidant-applications.