• Korean Journal of Environment and Ecology
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• v.31 no.3
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• pp.287-296
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• 2017

In order to check host plant diversity and to confirm the potential risk to be invaded, we documented host plant flora and plant part of C. pentagona, an invasive parasitic plant in field survey and induced parasitic infection by them in the laboratory experiment. Parasitic interaction(12% of total tree species) was found in twig and leaf of tree such as Quercus mongolica and Abies holophylla that was not developed into ligninfication. There were most host plant species belong to Compositae, but the species parasitic rate of family was higher in Cyperaceae, Polygonaceae and Leguminoceae. Through the inducible infection experiment with C. pentagona, all species except one species show parasitic interaction between host plan and C. pentagona. These result means that the limiting stage for invading area is dispersion process for invading other area in Korea. Infection plant part by C. pentagona was dominantly both shoot and leaf, rather than only leaf or only shoot. We found newly 12 families and 45 host plant species including 33 herbacious one and 12 woody one. Crop plant such as Setaria italica and 6 endangerd one such as Scrophularia takesimensis, especially the later rare endemic plant was to death by parasitic infection of C. pentagona. These results indicate that C. pentagona is potential risk to both wild and cultivated plant in Korea.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.323-330
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• 2006

The morphology and somatic chromosome numbers of Korean Parasenecio were investigated to estimate their taxonomic values. Some morphological characters, such as the length of whole plants, the numbers of cauline leaves, the shapes of leaf and petioles, the numbers of involucral bracts, floret numbers per head, presence of trichomes on the style, ratio between wide part and narrow part of floret and the size of achene were found to be a good characters for delimiting each taxa. Based upon these characters, six taxa, Parasenecio auriculala var. auriculata, P. auriculata var. kamtschatica, P. hastata subsp. orientalis, P. koraiensis, P. firmus, P. pseudotaimingasa, were recognized about their distribution in Korea, but 2 taxa, P. adenostyloides, P. auriculata var. matsumurana, were needed to be studied their taxonomic position and distribution in Korea. The somatic chromosome numbers of six taxa, P. adenostyloides, P. auriculata, P. auriculata var. kamtschatica, P. hastata subsp. orientalis, P. firmus, P. pseudotaimingasa were 2n=60 and those of P. firmus and P. pseudotaimingasa were reported first in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.69-89
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• 1981

Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.

• The Korean Journal of Ecology
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• v.25 no.5
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• pp.341-348
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• 2002

Correlations among the island area, distance to mainland, latitude, longitude, human impacts, diversity and composition of vascular plants were investigated by analyzing data on 261 islands(10.3% of total number of islands in Korea) selected from the annual reports for 'the natural evironment survey of the uninhabited islands in Korea' published by 'Ministry of Environment' during three years from 1999. The area of surveyed 261 islands ranged 1,100 to 961,000㎡(average of 75,000㎡), and the distance to mainland ranged 0.15 to 51.5km (average of 14.9km). Total number of plant species recorded in those islands was 1,109 species throughout 30 families, and mean mumber of plant species of each island was 98.7 species. Native species were 1,003 species (90.4%), and exotic species were 106 species(9.6%). The families with the largest number of species was the Compositae with 114 species, and followed in the order of Gramineae(90), Leguminosae(54), and Rosaceae(53). The result of multi-dimensional scaling analysis based on the plant species composition showed that 261 islands were distinctly divided into two groups, western sea group(131 islands) and southern sea group(130 islands). The islands of western sea group(average area of 93,000㎡) had greatly larger area than them of southern sea group(average area of 57,000㎡), but the average number of species (average species of 192) per island were less than in southern sea group (average species of 233). And, the partitioning into two groups was responsible for the species restricted to southern than to western sea group. Therefore, this results suggest that the distribution pattern and the composition of plant species could be also affected by the latitude of the island. When the species-area model was applied to total island and plant species, these results indicate that the island area was the most significant predictor of plant species diversity, and the distance to mainland and the human impacts were also shown to be significant predictors of plant species richness. But when applied to both groups of islands by the stepwise selection method, the result showed that islands of southern sea group were greatly affected by the factors such as human impacts, distance to mainland and longitude than western sea group. For the purpose of conservation of natural ecosystem on the uninhabited islands in Korea, we will also examine how the human impacts and the invasion of exotic plant species will disturb the native species diversity.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.871-876
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• 2010

Seven native and four introduced herbs namely $Thymus$ $quinquecostatus$, $Chrysanthemum$ $zawadskii$ var. $latilobum$, $Rosmarinus$ $officinalis$, etc. were selected for analysis of the DPPH radical scavenging and anti-microbial activity of their extracts. These perennial herbs are classified as $Labiatae$ and $Compositae$ except for $Saururus$ $chinensis$ and can be propagated through seedling and cuttage. These edible herbs are used as medicinal as well as ornamental plants. Their extract has electron donating ability which ranges from 69.7 to 78.7% for native herbs and 67.4 to 75.4% for introduced herbs. Native herbs have higher (3.54%) average DPPH radical scavenging than introduced herbs. In native herbs, maximum DPPH radical scavenging activity was observed in $Agastache$ $rugosa$ (78.7%) followed by $Saururus$ $chinensis$ while $Chamaemelum$ $nobile$ showed highest activity among the introduced herbs. Many herbs viz. $Saururus$ $chinensis$, $Chrysanthemum$ $zawadskii$ var. $latilobum$ and $Solidago$ $virga-aurea$ var. $gigantean$ showed excellent anti-microbial activity against gram positive $Enterococcus$ $faecalis$, maximum (80.0%) by $Saururus$ $chinensis$. Other herbs viz. $Solidago$ $virga-aurea$ var. $gigantea$, $Chrysanthemum$ $zawadskii$ var. $latilobum$, $Salvia$Salvia $plebeia$, $Chrysanthemum$ $indicum$, $Rosmarinus$ $officinalis$, $Chamaemelum$ $nobile$ and $Lavandula$ $stoechas$ showed anti-microbial activity against gram negative $Citrobacter$ $freundii$. Especially, the inhibition of colony growth of $Citrobacter$ $freundii$ was highest in the extract of $Chrysanthemum$ $zawadskii$ var. $latilobum$, and $Chamaemelum$ $nobile$.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.90-98
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• 2009

Every spring, Korea is always plagued by sandy dust from the western region of China and Mongolia. Yellow sand is causing an environmental problem to Japan and far into the American continent, let alone Korea. At present, the western region of China is going under desertification at a great speed due to climatic change and humans' damaging activities. To cope with this, each country including China is considering ecological restoration of deserts through planting. Accordingly, this research conducted a vegetation survey on Baicheng district which is a representative dry land of western China to obtain a basic data for ecological restoration of a desert. The survey revealed that Setaria viridis which invaded an arid land made a succession into Setaria viridis-Cannabis sativa var. fruderalis community together with Artemisia mongolica-Setaria viridis community due to the increase in salt concentration and alkalization subsequent to dryness. It was also found out that there finally formed Artemisia mongolica community on a flat intense in harsh wind and dryness with the continuous worsening of environmental conditions. There appeared a different type of vegetation on hilly districts where sporadic shade could come into being because the air humidity could be available relatively there. Frequently, typically appearing at the whole survey area, the Tributlus terrestris community was found to make succession into Tribulus terrestris-Cleisrogenes squarrosa community due to the aggravation of soil environment. In addition, with the worsening of the environment at hilly districts, there formed Clesirogenes squarrosa community resistant to dryness, salinity in soil and strong alkalinity. Further, there appeared higher plant life totalling to 62 taxa comprising 58 species and 4 varieties with 27 families and 49 genuses at the whole survey area. Among these, Compositae plants excellent in resistance to environment was surveyed the most, accounting for 27%.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.546-551
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• 2011

Chrysanthemums, often called mums or chrysanths, belong to the genus Chrysanthemum, which includes about 30 species of perennial flowering plants in the family Asteraceae. We extracted DNA from Dendranthema grandiflorum ('Smileball') to construct a simple sequence repeat (SSR)-enriched library, using a modified biotin-streptavidin capture method. GS FLX (Genome Sequencer FLX System which provides the flexibility to perform the broad range of applications) sequencing (at the 1/8 run specification) resulted in 18.83 mega base pairs (Mbp) with an average read length of 280.06 bp. Sequence analyses of all SSR-containing clones revealed a predominance of di-nucleotide motifs (16,375, 61.5%) followed by tri-nucleotide motifs (6,616, 24.8%), tetra-nucleotide motifs (1,674, 6.3%), penta-nucleotide motifs (1,283, 4.8%), and hexa-nucleotide motifs (693, 2.6%). Among the di-nucleotide motifs, the AC/CA class was the most frequently identified (93.5% of all di-nucleotide types), followed by the GA/AG class (6.1%), the AT/TA class (0.4%), and the CG/GC class (0.03%). When we analyzed the distribution of different repeat motifs and their respective numbers of repeats, regardless of the motif class, of 100 SSR markers, we found a higher number of di-nucleotide motifs with 70 to 80 repeats; we also found two di-nucleotide motifs with 83 and 89 repeats, respectively, but their product lengths were within optimum size (297 and 300 bp). In future work, we will screen for polymorphisms of possible primer pairs. The results will provide a useful tool for assessing molecular diversity and investigating the population structure among and within Chrysanthemum species.