• Journal of the Korean Wood Science and Technology
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• v.46 no.2
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• pp.118-124
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• 2018

Juglans mandshurica is a fast growing hard species, which is a tree in family of Juglandaceae and has a wide distribution in China, Korea and eastern Russia. Plant materials from J. mandshurica have extensively been used in folk medicines to prevent or cure gastric, esophageal, lung and cardiac cancer. As one chain of our searching for anticomplementary agents from natural sources, two epimeric ellagitannins, [2,3-O-4,4',5,5',6,6',-hexahydroxydiphenoyl (HHDP))-(${\alpha},{\beta}$)-D-glucose] (I) and pedunculagin (II) were purified from 70% acetone extracts of the stem barks of J. mandshurica by Thin Layer Chromatography and Sephadex LH-20 column chromatography approaches. The chemical structures of the isolated compounds were characterized by MS, NMR, and a careful comparation with published literatures. The epimeric ellagitannins I and II exhibited inhibitory properties against a classical pathway of complementary system with 50 % inhibitory concentrations ($IC_{50}$) values of 65.3 and $47.7{\mu}M$, respectively, comparing with riliroside ($IC_{50}=104{\mu}M$) and rosmarinic acid ($IC_{50}=182{\mu}M$), which were used as positive controls. Thus, the work indicated both the two secondary metabolites possess excellent inhibitory activity and might be developed as potential anticomplementary chemicals.

• Molecules and Cells
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• v.25 no.2
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• pp.163-171
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• 2008

The genus Cynodon comprises ten species. The objective of this study was to evaluate the genetic diversity of Korean bermudagrasses at the morphological, cytological and molecular levels. Morphological parameters, the nuclear DNA content and ploidy levels were observed in 43 bermudagrass ecotypes. AFLP markers were evaluated to define the genetic diversity, and chromosome counts were made to confirm the inferred cytotypes. Nuclear DNA contents were in the ranges 1.42-1.56, 1.94-2.19, 2.54, and 2.77-2.85 pg/2C for the triploid, tetraploid, pentaploid, and hexaploid accessions, respectively. The inferred cytotypes were triploid (2n = 3x = 27), tetraploid (2n = 4x = 36), pentaploid (2n = 5x = 45), and hexaploid (2n = 6x = 54), but the majority of the collections were tetraploid (81%). Mitotic chromosome counts verified the corresponding ploidy levels. The fast growing fine-textured ecotypes had lower ploidy levels, while the pentaploids and hexaploids were coarse types. The genetic similarity ranged from 0.42 to 0.94 with an average of 0.64. UPGMA cluster analysis and principle coordinate analysis separated the ecotypes into 6 distinct groups. The genetic similarity suggests natural hybridization between the different cytotypes, which could be useful resources for future breeding and genetic studies.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.566-577
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• 2015

White Jabon (Anthocephalus cadamba Miq.) is one of the fast growing species in Indonesia and has the potential as the raw material for pulp and paper. In this research, 3, 5, and 7 years old White Jabon woods were pulped under different active alkali charge of 15%, 18%, 21%, 24%, and 27%, and its effect on delignification degree, kappa number, pulp yield, pulp viscosity, brightness, unbeaten freeness, and delignification selectivity was investigated. The results showed that tree age and active alkali concentration influenced the quality of pulp and pulping properties, except for that of unbeaten freeness. Delignification degree increased with increasing active alkali charge, and this brought about the decrease of pulp kappa number. The pulping yield tended to decrease below the Klason lignin of approximately 4%. Even though the 3 years old wood resulted in the highest brightness and highest delignification selectivity, the highest pulp viscosity was obtained with the 5 years old wood. The dominant fiber length of all wood ages was in the range of 1.2 - 2.0 mm. The 3 years old wood was considered to be the most promising raw material for kraft pulping in the view point of pulping properties, pulp quality and harvesting rotation.

• Journal of Life Science
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• v.21 no.9
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• pp.1281-1287
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• 2011

Phyllostachys consists of high and fast growing trees and is a genus in the family Gramineae. The genus has many species in Asia, with main distribution being in India and China. One of the most popular sequences for phylogenetic inference at the generic and infrageneric levels in plants is the internal transcribed spacer (ITS) region of the 18S-5.8S-26S nuclear ribosomal cistron. We evaluated four taxa with the ITS region to estimate phenotypic relationships within the genus Phyllostachys in Korea. Alignment of the DNA sequences required the addition of numerous gaps. Sequence variation within the Phyllostachys was mostly due to natural selection, although several indels and inserts were found. Within the genus Phyllostachys, P. nigra and P. nigra var. henonis were the relatives in the three phylogenetic analyses (MP, ML, and NJ). However, some external nodes were poorly supported. Morphological traits and simple repeats (ISSR) represented the result of a relationship similar to the that of ITS sequences in the genus Phyllostachys. This suggests that ITS sequences are very informative for identification of these taxa.

• Research in Plant Disease
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• v.27 no.2
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• pp.49-60
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• 2021

Cashew (Anacardium occidentale L.) is an important cash crop in Tanzania as a source of income to cashew growers and provides foreign exchange for the country. Despite its significance, the crop is threatened by fast spreading disease known as cashew Fusarium wilt caused by Fusarium oxysporum. Field assessment and laboratory tests were conducted to determine incidences of the disease, severity, ecological factors that influence them and explored the pathogen host specificity in six cashew growing districts. The results revealed significant (P<0.001) variation of disease incidences and severity among the studied districts. The results further revealed that there is both positive and negative correlation between the incidence and severity of the disease versus the evaluated ecological factors. The soil pH, soil temperature, air temperature, and relative humidity depicted positive correlation of disease incidence and severity versus ecological factors at ρ=0.50 and ρ=0.60, ρ=0.20 and ρ=0.94, ρ=0.11 and ρ=0.812, ρ=0.05 and ρ=0.771 respectively while nitrogen, phosphorus, and carbon depicted negative correlations at ρ=-0.22 and ρ=-0.58, ρ=-0.15 and ρ=-0.94, ρ=-0.19 and ρ=-0.12 respectively. In terms of host range, none of the weed species was found to be a carrier of Fusarium pathogen implying that it is host specific or semi selective. The results revealed that the tested ecological parameters favor the growth and development of Fusarium pathogen. Thus, management of the disease requires nutrients replenishment and soil shading as essential components in developing appropriate strategies for the control and prevention of further spread of the disease.

• Journal of Life Science
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• v.22 no.7
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• pp.987-990
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• 2012

Mungbean sprout rot is one of the most serious problems of the commercial mungbean sprout industry. In this study, 70 strains of mungbean sprout rot pathogens were isolated from rotten sprouts at different time intervals. The pathogenicity of the isolated pathogens was tested. The highly pathogenic strain (YV-St-033) was identified as Pseudomonas sp. by 16S rRNA gene sequencing. In phylogenetic analysis, the YV-St-033 strain was grouped with P. mosselii, P. putita, P. fluorescens, P. entomophila, and P. lecoglossicida. The results of the 16S rRNA gene sequence analysis revealed that the YV-St-033 strain shared the highest sequence identity (more than 99%) with the P. mosselii R10 strain. The mungbean lines of Yeungnam University germplasm were screened against the YV-St-033 strain. Based on the growth rate of the sprouts after 3 days of inoculation with the pathogen, the YV148 line was highly resistant to the pathogen. The remaining lines were either partially or fully infected. The highly resistant line YV 148 is suitable for future breeding programs due to their thin sprouts and fast growing nature.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.1-20
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• 2000

There are increasing evidences of climate change in the Antarctic and Arctic Oceans, especially elevated temperature due to the continuous burning of the fossil fuels and ultraviolet B(UV-B) flux within the ozone hole. Light-dependent, temperature-sensitive, and fast-growing organisms respond to these physical and biogeochemical changes. Polar marine phytoplankton, which are pioneer endemic species and important carbon contributors in the polar waters, are therefore highly suitable biological indicators of such changes. By virtue of light requirement, the primary producers are exposed to extreme seasonal fluctuations in temperature, photosynthetically active radiation, and UV radiation. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the polar water. Small changes in climate temperature and solar radiation may have profound effects on the activity threshold of the polar phytoplanktion. To demonstrate biological response to the environmental changes, standardized representative natural and biological parameters are needed so that replicate samples (including controls) can be taken over extended periods of time. In this paper, we review general characteristics of polar phytoplankton, their environment, environmental changes in the polar waters, the effects on the environmental changes to the polar phytoplankton, and the importance of the polar phytoplankton to understand the global environmental changes. [Biological indicators, Global environmental change, Polar phytoplankton, UV].

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.431-446
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• 2023

Samama wood (Anthocephalus macrophyllus (Roxb) Havil) is a fast-growing and lesser-utilized wood species that has inferior properties; therefore, its quality needs to be improved. This research aimed to determine the effect of citric acid impregnation at high curing temperatures on the dimensional stability and mechanical properties of wood. Citric acid solution with 10% concentration (w/w) was impregnated into wood samples by vacuum-pressure method (-0.5 cmHg, 30 min; 0.7 MPa, 3 h), followed by curing process at 140℃, 160℃, and 180℃ of temperature for 1 h. In comparison, the other wood samples were heat treated at the same temperatures and time. The results showed that the increase in curing and heat temperatures for both treatments were directly proportional to the dimensional stability, but inversely proportional to the mechanical properties. Citric acid impregnated had higher density, dimensional stability, and mechanical properties, except for modulus of rupture, than that of heat treatment. The optimum temperature is suggested at 160℃ in both treatments.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.71-81
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• 2014

A survey was carried out to understand the influence of hydrology on the composition, abundance and adaptive strategies of phytoplankton in artificial Lake Hwaseong, an estuarine reservoir with seawater exchange through a sluice. Samples were collected seven times from May to October 2012. Hydrological events (seawater exchange, rainfall) resulted in a wide variation in salinity along with nutrients and turbidity. Shifts in the dominant phytoplankton composition occurred on every survey. Chlorophyll-a ranged from 9.7 to $104.1{\mu}g\;L^{-1}$. Multivariate analysis allowed us to identify the four phases on phytoplankton community change. Phase I (May~June) was characterized by small-sized Gymnodinium sp. and Heterosigma akashiwo dominated in warm temperature and high salinity derived from seawater exchange, and followed by Cylindrotheca closterium blooms due to rainfall and winds during phase II (July and September). During phase III (August), the dominance of Oscillatoria spp. was correlated with high temperature and low salinity. Abundant cryptomonads were associated with lower temperature during phase IV (October). Adaptive strategies were identified in the phytoplankton as morphological and physiological characteristics. These strategies identified small-sized flagellates as CR-strategists, fast-growing opportunistic species, which might favor the weak stratification of lake due to the seawater exchange during phase I and IV. Dominant species during phase II and III were characterized with R-strategists, medium-sized stress-tolerant species, which might favor turbulence by river flow. The results indicate that stronger stratification following the termination of seawater exchange for the freshening might intensify the predominance of smaller flagellates. In conclusion, this study suggests that hydrology may drive phytoplankton community change and blooms through the controls of salinity, turbulence and nutrients.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.16-24
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• 2015

This study quantified storage and annual uptake of carbon for riparian greenspaces established in watersheds of four major rivers in South Korea and explored desirable strategies to improve carbon reduction effects of riparian greenspaces. Greenspace structure and planting technique in the 40 study sites sampled were represented by single-layered planting of small trees in low density, with stem diameter at breast height of $6.9{\pm}0.2cm$ and planting density of $10.4{\pm}0.8trees/100m^2$ on average. Storage and annual uptake of carbon per unit area by planted trees averaged $8.2{\pm}0.5t/ha$ and $1.7{\pm}0.1t/ha/yr$, respectively, increasing as planting density got higher. Mean organic matter and carbon storage in soils were $1.4{\pm}0.1%$ and $26.4{\pm}1.5t/ha$, respectively. Planted trees and soils per ha stored the amount of carbon emitted from gasoline consumption of about 61 kL, and the trees per ha annually offset carbon emissions from gasoline use of about 3 kL. These carbon reduction effects are associated with tree growth over five years to fewer than 10 years after planting, and predicted to become much greater as the planted trees grow. This study simulated changes in annual carbon uptake by tree growth over future 30 years for typical planting models selected as different from the planting technique in the study sites. The simulation revealed that cumulative annual carbon uptake for a multilayered and grouped ecological planting model with both larger tree size and higher planting density was approximately 1.9 times greater 10 years after planting and 1.5 times greater 30 years after than that in the study sites. Strategies to improve carbon reduction effects of riparian greenspaces suggest multilayered and grouped planting mixed with relatively large trees, middle/high density planting of native species mixed with fast-growing trees, and securing the soil environment favorable for normal growth of planting tree species. The research findings are expected to be useful as practical guidelines to improve the role of a carbon uptake source, in addition to water quality conservation and wildlife inhabitation, in implementing riparian greenspace projects under the beginning stage.