• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.163-167
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• 2002

This study was carried out to investigate the effect of minimum night temperature in the PE house on growth of seedlings of Pinus densiflora and Betula platyphylla in winter season. The experiment was performed with three minimum night temperature regimes,5~8$^{\circ}C$, 10~13$^{\circ}C$ and 15~18$^{\circ}C$. The temperature regimes were maintained for 8 weeks (to April 6) after germination peak, and then were broken by increasing natural temperature. The temperature did not affect the germination rate but delayed the germination by 10 days. Height, root collar diameter growth, and dry weight of two species were reduced by relatively low night temperature. The reduction was more obvious in the dry weight of above the ground measured at 8 weeks after germination. The seedlings grown for 8 weeks at 5~8$^{\circ}C$ showed the lowest T/R ratio. It was also observed that the height growth response in Betula platyphylla seedlings to relatively low temperature was more sensitive than Pinus densiflora.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.481-495
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• 2015

The study researched germination of the plants and growth of Fungus according to concentration of aqueous extracts in order to provide basic data for developing natural agricultural resources by using Persicaria longiseta. The seed germination of Amaranthus spinosus was inhibited at 25% P. longiseta extract, while Agrostis stolonifera ssp. palustris was not affected at all concentrations tested. Especially, the seed germination rate and fresh weight of Trifolium incarnatum at 20% P. blumei extract were higher than those of control plot. The early growth of most receptor plant seedlings was promoted at 25% and 50% of P. blumei extracts, but the radicle growth of all receptor plants was significantly inhibited at > 25% of P. longiseta extract. The response of receptor plants to P. longiseta extract was different according to the plant species and the plant parts. The growth of plant pathogenic fungus in PDA medium showed an increasing inhibition tendency with increasing concentrations of P. longiseta extract. Especially, P. longiseta extract showed the greatest antimicrobial activity against Phytophthora infestans, Phythium graminicola, and Pythium venterpoolii. The content of total phenolic compound in P. longiseta was higher in leaves (1082.3 mg/L) but lower in roots (228.6 mg/L) and stems (207.8 mg/L), which is an allelopathic chemical. As these results are summarized, P. longiseta have competitive advantage because they release phenolic compounds with allelopathic effect and affect on germination, growth and fungi growth on underground flora compared to native plants and they have eligibility for natural herbicide and germicide.

• 농업기술회보
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• v.49 no.3
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• pp.37-38
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• 2012

우박에 의한 배 과수원의 피해가 매년 발생하고 있으나, 피해 후 이듬해 수세회복을 위한 연구결과가 부족하여 농가에 어려움을 주고 있다. 과실생장 초기인 6월초에 우박피해를 받은 배 과수원의 피해 정도에 따라 충실한 꽃눈을 확보할 수 있는 기술을 알아본다.

• Korean Journal of Environment and Ecology
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• v.17 no.4
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• pp.309-315
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• 2004

To estimate planting results of deciduous broad-leaved species, forest structure and radial growth of the trees were investigated and compared by species and studied sites. Plantation forest studied on Juglans mandshurica, was located at Jawoon-ni Nae-myeun, Hongcheon-gun and natural forest studied on Juglans mandshurica, was located at Jangjeon-ni Jinbu-myeun, Pyeungchang-gun. In 9 years after planting, differences of annual diameter increment among three stand origins were significant. The highest mean annual diameter increments of J. mandshurica, 7.31mm/year was measured in natural seedlings, and followed by sprouting trees 6.93mm/year. The lowest values, 5.28mm/year did in planting trees. Early radial growth of planting J. mandshurica was measured lower than that of sprouting or natural seedlings. These facts means that planting J. mandshurica is not proper regeneration methods. Other regeneration methods of J mondshurica forest, by sproutings, direct seeding and natural seeding, might be researched and recommended.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.255-262
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• 2004

Growth patterns after the cutting and burning of Miscanthus sacchariflorus community were analyzed in the Woopo Wetland. Three replicates of 5 ${\times}$ 5 m plot of control, burning, and cutting treatments were established in April 2003 and changes of growth pattern were monitored by August 2003. In the control, burning, and cutting plots, a total of 7 families and 8 species, 14 families and 18 species, 6 families and 8species were observed respectively. Burning plot showed high diversity of flora. However, high diversity declined after July and all plots showed a similar species diversity. Vine plant, Humulus japonicus, dominated in the burning plots. Change of shoot density was highest in the early period in the burning plots (176/$m^2$) and shoot density in early May was almost double of the control and cutting plots. Toward to the end of active growth period (August), shoot density in cutting plot (170 ${\pm}\;7/m^2$)was higher than that of burning plots (141 ${\pm}\;9/m^2$). Shoot length of the cutting, burning, and control plot was 205 ${\pm}$ 15 cm, 190 ${\pm}$ 17 cm, and 187 ${\pm}$ 6 cm (n> 100) respectively. Above- ground biomass of cutting plots was higher than that of burning and control plots. Above- ground biomass of cutting plot was 1.6 times higher than the control while burning plot showed 1.4 times. This study indicted that cutting of Miscanthus sacchariflorus community increase shoot density development, length growth, and above- ground biomass.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.80-86
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• 1997

The objective of this study was to investigate how resistant poplar hybrid makes compensation to ozone stress. Growth, net assimilation rate and initial Rubisco activity were investigated. This study elucidates the physiological mechanisms associated with ozone sensitivity and resistance in 3 selected $F_2$ hybrids, a family originating from a cross between Populus trichocarpa${\times}$P. deltoides. Open-top chambers were used. Ozone concentrations varied from 90 to 115 ppb for 126 days, 6 to 9 hours in a day. This study tested the hypothesis that resistant poplar hybrid maintains the biomass production to ozone exposure via increased net assimilation rate and Rubisco activity. Growth, biomass, net assimilation rate and initial Rubisco activity were generally reduced by ozone treatment. In the tree parts, root under ozone stress was the most sensitive part. Reduced allocation of photosynthates to root growth might be due to increased respiratory demands for maintenance and repair of aboveground tissue damaged by ozone stress. Maintenance or increases remaining leaves in photosynthetic rates and Rubisco activity in resistant clone in response to ozone treatment were the results of biological compensation to ozone stress.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.53-61
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• 2012

This study was conducted to clarify reasonable root pruning and transplanting density for efficient production of seedlings of Quercus species, which is a representative planting species in Korea. Seedlings of Q. acutissima and Q. serrata, which were pruned roots by 5 cm, showed poorer above-ground and root growth compared to those pruned by 10 cm and 15 cm, and growth performance of seedlings pruned by 10 cm was shown similarly those pruned by 15 cm. The growth performance of seedlings transplanted in the density of below 64 seedlings per $m^2$ was greater than those transplanted in the density of over 81 seedlings per $m^2$. Therefore, one-year-old seedlings of Q. acutissima and Q. serrata should be transplanted in the density of 64 seedlings per $m^2$ after pruning their roots by 10 cm to obtain excellent growth performance and increase the efficiency of transplanting. The results of this study can be used as baseline for producing superior seedlings of Q. acutissima and Q. serrata at nursery and understanding early transplanting performance of the species.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.285-296
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• 2014

The impacts of high temperature and drought were studied on the seedlings of three families (superiorgangwon74, intermediate-gangwon77 and inferior-gangwon132) of P. densiflora which had been selected by the based on the growth indexes of 32-year-old. The seedlings were grown in controlled-environment growth chambers with combinations of four temperatures ($-3^{\circ}C$, $0^{\circ}C$, $+3^{\circ}C$ $+6^{\circ}C$; based on the monthly average for 30 years in Korea) and two water conditions (control, drought). The growth performance, photosynthetic parameters and photosynthetic pigment contents were measured at every 30 days under four temperatures and drought condition, and the end of each treatment. The superior family showed higher relative diameter at root collar growth rate and the dry weight than intermediate and inferior family in all treatments. Under elevated temperature and drought condition, growth rate was decreased, and seedlings showed lower growth rate than that of control in three families under low temperature. Photosynthetic rate, stomatal conductance and transpiration rate of three families decreased with the increase of temperature and drought condition, and that of seedlings under low temperature was lower than control. But under elevated temperature and drought condition, water use efficiency increased in three families. Photosynthetic pigment contents of leaves decreased under the increase of temperature and drought condition, but chlorophyll a/b ratio increased with the increase of temperature and drought condition in three families. The superior family showed higher total chlorophyll content than intermediate and inferior family in all treatments. In conclusion, P. densiflora is under changed temperature and drought condition, growth was decreased, seedlings more affected in elevated temperature than that of decreased temperature. The increase in monthly average temperature in Korea of more than $6^{\circ}C$, P. densiflora seedling growth in depending on region may decrease. In this study, the superior family(gangwon74) showed more excellent growth and physiological responses than intermediate (gangwon77) and inferior(gangwon132) family under changes temperature and drought.

• Journal of Plant Biology
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• v.35 no.4
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• pp.359-364
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• 1992

The vascular cambium in Ginkgo biloba seedling began to differentiate in the cotyledonary node, and then the differentiation proceeded bidirectionally from the cotyledonary node toward the stem and root. In tangential view, procambium at the early developmental stage was a homogeneous structure consisted of almost similar cells in shape, and at the later stage the procambium became a heterogeneous one consisted of long cells and short cells. Such a differentiation pattern in the cotyledonary node was similar to that in the stem. However, it was different from that in the root. Fusiform initials and ray initials consisting the vascular cambium were originated from the long cells and the short cells, respectively. The long cells and the fusiform initials in the cotyledonary node were shorter and wider than those in the first internode.ernode.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.301-304
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• 2002

Perfusion culture strategies for high density culture of plant cell suspensions to enhance the productivity of extracellular polysaccharides were investigated. Angelica gigas Nakai cell suspensions were used to produce the extracellular polysaccharide and perfusion parameters were optimized to maximize the production. When the medium exchange was started at the fifth day after inoculation, the maximum cell concentration (23.8 g dry cell weight per liter) was achieved.