• Plant Biotechnology Reports
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• v.3 no.3
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• pp.175-182
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• 2009

Simple, reproducible, high frequency, improved plant regeneration protocol in Eastern Cottonwood (Populus deltoides) clones, WIMCO199 and L34, has been reported. Initially, aseptic cultures established from axillary buds of nodal segments from mature plus trees on MS liquid medium supplemented with $0.25mg\;1^{-1}$ KIN and $0.25mg\;1^{-1}$ IAA. Nodal and internodal segments were found to be extra-prolific over shoot apices during course of aseptic culture establishment, while $0.25mg\;1^{-1}$ KIN concentration played a stimulatory role in high frequency plant regeneration. Diverse explants, such as various leaf segments, internodes, and roots from in vitro raised cultures, were employed. Direct plant regeneration was at high frequency of 92% in internodes, 88% in leaf segments, and 43% in root segments. This led to the formation of multiple shoot clusters on established culture media with rapid proliferation rates. Many-fold enhanced shoot elongation and growth of the clusters could be achieved on liquid MS medium supplemented with borosilicate glass beads, which offer physical support for proliferating shoots leading to faster growth in comparison to semi-solid agar or direct liquid medium. SEM examination of initial cultures confirmed direct plant regeneration events without intervening calli. In vitro regenerated plants induced roots on half-strength MS medium with $0.15mg\;1^{-1}$ IAA. Rooted 5- to 6-week-old in vitro regenerated plants were transferred into a transgenic greenhouse in pots containing 1:1 mixture of vermicompost and soil at $27{\pm}2^{\circ}C$ for hardening and acclimatization. 14- to 15-week-old well-established hardened plants were transplanted to the field and grown to maturity. The mature in vitro raised poplar trees exhibited a high survival rate of 85%; 4-year-old healthy trees attained an average height of 8 m and an average trunk diameter of 25 cm and have performed well under field conditions. The regeneration protocol presented here will be very useful for undertaking genetic manipulation, providing a value addition to Eastern Cottonwood propagation in future.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.186-195
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• 2017

This research aims to study the physiological characteristics of poplar clones in Saemanguem reclaimed land where has lower minerals and bad drainage than those in paddy field. In July and August, different poplar clones including Populus euramericana clone (Venziano and L.Avanzo) and deltoides hybrid clone (97-18 and 97-19) showed different physiological characteristics. Physiological characteristics of P. euramericana clones were better than those of P. deltoides hybrid clones. Especially, the average net photosynthetic rate ($A_{net}$) of clone Venziano were $18.62{\mu}mol\;CO_2\;m^{-2}{\cdot}s^{-1}$ and $17.11{\mu}mol\;CO_2\;m^{-2}{\cdot}s^{-1}$, respectively. Those were the highest numerical values among other poplar clones. On the other, the total chlorophyll and carotenoid contents of P. deltoides hybrid clones were higher than those of P. euramericana clones in July. Particularly, the total chlorophyll content of clone 97-18 was $2.37mg{\cdot}g^{-1}FW$. In August, those of P. deltoides hybrid clones decreased than in July. In term of the physiological activity such as net photosynthetic rate and stomatal conductance of P. deltoides hybrid clones were much lower in August than in July. As a result, physiological characteristics of P. euramericana Venziano clone was superior than the other clones in Short rotation coppice (SRC) in Saemanguem area.

• Journal of Korean Society of Forest Science
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• v.49 no.1
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• pp.32-33
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• 1980

Several plants of Populus deltoides 'R-89' exhibiting symptoms of poplar mosaic described earlier by several researchers (1,2,3) were observed in the poplar nursery of the Institute of Forest Genetics at Suweon, Korea during September, 1980. The symptoms produced a mosaic or discolored yellow spottings in mature leaves with veinal and petiolar necrosis and leaf curling (Fig. 1 and 2). Leaves with mosaic symptoms were collected and leaf-dip preparations from chlorotic area were examined for the presence of virus particles with an electron microscope. Electron micrographs of the negatively stained leaf-dip preparations revealed numerous elongated virus particles ranging 200-1300nm in length (Fig. 3). Of 156 panicles measured randomly, 68 particles (43.6%) were in the range of 660-670nm in length (Fig. 4). The values obtained fell well within the range of those described for poplar mosaic virus (PMV) by other researchers (1. 2, 3). No viruslike particles were observed from poplar leaves without mosaic symptoms. Further studies on the properties of the PMV isolate and control of the disease are underway.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.403-409
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• 2005

Mature nodal segments of 2-year-old greenhouse stock plant were cultured on Murashige and Skoog basal medium supplemented with the different kinds and various concentrations of cytokinins to produce multiple shoots in in vitro condition. The most adventitious shoots were produced from excised ends of nodal segments. The highest average number $(24.6\;{\pm}\;4.6)$ of shoots was produced with the combination of BA 1.0mg/L and TDZ 0.1mg/L in MS medium. In addition, several shoots were formed from lenticels of bark cambium with the same treatment. These concentrations promoted high shooting capability upto $94.6\%$ and NAA was the best cytokinin among five different PGR sources.

• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.329-334
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• 1997

Adventitious organs (shoots and roots) from mature leaves of Populus deltoides (Eastern cottonwood) clones were induced on WPM (Woody Plant Medium) containing fructose as a carborn source and different combinations of either BA (Benzyl aminopurin) or TDZ (Thidiazuron) with NAA (Naphthaleneacetic acid). The morphologies of adventitious shoots were different depending on the kinds of growth regulators and the length of shoots induced on the medium containing BA were generally longer than that of TDZ. BA 0.5 mg/L and TDZ 0.01 mg/L combined with either 0.05 or 0.1 mg/L NAA showed the highest values in the frequency of regeneration (63% to 100%) the number of shoots per explant and in the organogenic sites per explant among tested three clones (A, B and C). Although there was a minor clonal difference in the development of adventitious shoots from leaf segments, their responses to growth regulators were very similar.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.261-269
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• 1997

Excised immature ovules and calli derived from the stems of cottonwood were bombarded with microprojectiles carrying plasmid DNA containing CaMV-35S promoter and ${\beta}$-glucuronidase(GUS) gene. After bombarded, the expression of GUS gene was detected by the assay of 5-bromo-4-chloro-3-indolyl-${\beta}$-gluconide(X-gluc). Transient gene expression was measured by counting the number of distinct regions of GUS activity per explant. As major parameters, the number of shots and the period of exposure to X-gluc after the bombardment were investigated for detecting GUS gene expression. In this experiment, the percents of GUS gene expression showing spots were 56.8 from immature ovules and 75.9 from micro-calli of cottonwood species. Among the treatments, two consecutive shots and 48 hour exposure produced about $25.75{\pm}2.77$(per ovule), $11.43{\pm}1.22$(per mini petridish) spots, respectively, Microprojectile particle bombardment provides a useful method to assay transient expression in both types of explants. Furthermore, our results represent that the excised ovule and/or the calli might be stably transformed by the biolistics.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.15-21
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• 2010

We estimated the biomass productivity and the storage potential of nitrogen, the major contributor of non-point source pollution, with four three-year-old four poplar clones in a riparian woody buffer established in the Anseong River in Anseong, Korea. Stem of Populus alba ${\times}$ P. glandulosa clone 72-31 and Populus deltoides ${\times}$ P. nigra clone Dorskamp showed the highest percentage of aboveground biomass components, followed by branch and leaf. Nitrogen content in aboveground biomass components of two poplar clones was the highest in leaf and the lowest in stem. Nitrogen content in leaf and branch of clone 72-31 was higher than that of clone Dorskamp, while it in stem was lower. Populus deltoides clone Ay48 showed the highest above-ground biomass productivity, which was estimated as $37.5ton\;ha^{-1}$ at age 3. However, clone 72-31 was the lowest in above-ground biomass productivity. Nitrogen storage potential in aboveground biomass of 3-year-old poplar clones was high in order of aboveground biomass. Clone Ay48 showed the highest nitrogen storage potential in aboveground biomass, which was estimated as $218.3kg\;ha^{-1}$ at age 3.

• Plant Resources
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• v.7 no.2
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• pp.87-92
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• 2004

Five different poplar hybrids were tested for rescuing embryo to elongate in vitro plantiets after hybridization. Ovaries and ovules were cultured on Woody Plant Medium (WPM) supplemented with cytokinins, 6-benzylamine (BA) and zeatin. Multiple shoots were initiated from half section of capsule with immature embryos after 21 days from pollination and tiny shoots were formed after the expansion of cotyledons in ovule cultures. Germinating response was better in intraspecific hybrids $(6.53\pm1.66)$ than interspecific crosses $(0.93\pm0.54)$ from half section of capsules on WPM medium. In general, zeatin was better than BA in inducing multiple shoots from isolated ovules. The highest average number $(19.40\pm4.53)$ of shoots was produced from immature ovules of 21 days post-pollination of WPM medium supplemented with 5.0 mg/L zeatin. The highest percentage of germination was 93% from the half section of in vitro ovary cultures. Soil acclimation was successfully conducted in cell tray containing artificially mixed soil with 96% survival rate.

• Journal of Mushroom
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• v.7 no.4
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• pp.156-162
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• 2009

These experiments were carried out to determine the optimal culture conditions for nine strains of collected Hatakeshimeji, Lyophyllum decastes (Fr.:Fr.) Sing. SPA 202 and SPA 205 strains were selected because mycelium grew fast and showed fine density. All strains showed fast mycelial growth and mycelial density on BC(Burke compost) media for 20 days of incubation. The optimal sawdust species for the mycelial growth were the fermented sawdusts of Quercus aliena and Populus deltoides. Spawn running period on the fermented sawdust substrate required 50 days at 20 to $25^{\circ}C$ and additional 7 days after soil casing. Cultivation period and temperature forprimordia formation and fruitbody development appeared from 10 to 11 days and from 7 to 8 days at 17 to $18^{\circ}C$ respectively. The length of pilei and stipes of SPA 202 harvested in optimal stage showed 60mm and 67mm, respectively. Yield of SPA 202 strain grown on fermented sawdust substrate was 130g per 1,100ml in bottle cultivation. The length of pilei and stipes of SPA 205harvested in optimal stage showed 51mm and 81mm, respectively. Yield of SPA 205 strain grown on fermented sawdust substrate was 129g per 1,100 ml in bottle cultivation. SPA 202 strain and SPA 205 strain in artificial bottle cultivation of Lyophyllum decastes used in fermented sawdust substrate were selected as themost appropriate strain in yield.

• The Korean Journal of Ecology
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• v.24 no.2
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• pp.93-100
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• 2001

One-year-old cottonwood (Populus deltoides Bartr.) clones, which were classified as sensitive or tolerant, were exposed to 150 n1/1 ozone (O$_3$) over 8 days for 8 hours each day under glass chamber conditions with natural sunlight. The leaves of the sensitive clone had black stipple and bifacial necrosis after $O_3$ treatment. Photosynthesis and stomatal conductance were measured before, during, and after the $O_3$ treatment. The photosynthetic rates due to $O_3$ treatment were decreased 51 percent and 34 percent on the sensitive and tolerant clone, respectively. The stomatal conductance of the sensitive clone was more than 40 percent higher than that of the tolerant clone regardless of the $O_3$ treatment. As light intensity increased, the $O_3$ effect on photosynthesis was clear. Compared to the previous growth chamber studies, our natural light exposure system was able to maintain a stable photosynthetic responses of the control treatment throughout the fumigation period. In addition, changes in assimilation versus intercellular $CO_2$ concentration (A/C curves) showed that $O_3$ decreased the slope and asymptote of the curves for the sensitive clone. This indicates that $O_3$ decreases the biochemical capacity of photosynthesis on the sensitive clone. Chlorophyll contents and fluorescence of the two clones were analyzed to examine the $O_3$ effects on photosystem 11, but $O_3$ did not impact these variables on either clone. Although the tolerant clone did not show any foliar injury, we could not find any ecophysiological defensive responses to $O_3$ treated. Stomatal conductance of the tolerant clone was originally much lower than that of the sensitive one. Thus, the mechanisms of the tolerant clone in this system are to narrowly open stomata and efficiently maintain photosynthesis with a more durable biochemical apparatus of photosynthesis under $O_3$ stress. The sensitive clone has higher photosynthetic capacity and more efficient light reaction activity than the tolerant one under charcoal filtered condition, but is not as resilient under stress.