• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.121-126
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• 1995

Diploid plants were obtained by anther culture of tetraploid poplar(Populus alba L. X P.glandutosa Uyeki). The effect 2,4D on callus formation from anther culture was greater than any other auxins tested. The highest average number of multiple shoots per callus was obtained when zeatin was used at levels of 6-8 ${\mu}$M. Regenerated shoots were excised and transferred to MS basal medium. Rooted plantlets were subsequently transferred to pots containing artificial soil mix. Finally 100 plane were transplanted in nursery located in forest Genetics Research Institute. for the 300 anther clones growing in greenhouse for 6 months after transplanting, 33% were slow-growing, 47% were rapid-growing and 20% had huge leaf size with rapid-growing characteristics. Chromosome study showed a narrow range of variation from diploid to tetraploid. DNA polymorphism studies using various RAPD markers revealed some extend of differences among the anther-clones in their band pattern.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.291-296
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• 2012

Triploids are a useful tool for biomass production and molecular breeding of trees with a long life span. Triploids of the poplar 'Hyunsasi' (Populus alba ${\times}$ P. glandulosa) have been developed by crossing between female diploids and a male tetraploid. The tetraploid was developed around the 1970s at Korea Forest Research Institute by colchicine-induced chromosome doubling. Seedlings of the $F_1$ generation were analyzed using flow cytometry to verify their ploidy status. The mean relative fluorescence index of 3 F1 poplars, labeled as Line- 1, Line-17, Line-18, were approximately 1.5 times higher than those of diploid poplars, and the results clearly indicated that they were triploids. The phenotype of the F1 poplars included larger leaves and thicker stem than diploids, and abnormal leaf morphology, especially in the triploid 'Line-18'. Three triploid lines developed roots more slowly and had less roots than diploid. However, 3 poplar cytotypes (2x, Line-1, Line-17) rooted within 10 days on MS medium. In contrast, compared with the 3 cytotypes, the Line-18 showed about 80% and 70% in the rooting rate and the number of roots. The triploid poplars could be directly utilized for biomass production and with their sterility, they could serve as basic material for genetic transformation. In addition, flow cytometric analysis proved to be an effective and reliable method for screening forest trees for their ploidy level.

• Journal of Plant Biotechnology
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• v.3 no.2
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• pp.83-88
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• 2001

A cell culture system of poplar (Populus alba x P.glandulosa) was established to test four different methods for evaluation of cellular stresses. Two different kinds of stresses were given to the cultures by adding either Pb(NO$_3$)$_2$ or paraquat and the cellular responses were monitored during a week period. While fresh weight reduction was observable in two days after the treatment of Pb(NO$_3$)$_2$, such changes were apparent only in later stage in paraquat treated cultures. Cells in paraquat treated cultures in the first 3 days showed no alteration in fresh weight as compared to untreated cultures, but had their MTT reducing activities completely inhibited. Neither Evans blue staining nor ion conductivity of the medium was consistent with fresh weight changes of the cultures. Overall, cell clumps formed during suspension culture appeared to interfere with staining and washing reactions and thus cause the assays unreliable. Among the four methods examined, fresh weight changes and MTT reducing activity appeared to be the most reliable and consistent.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.343-356
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• 2010

Plant micropropagation techniques include bud cultures using apical or axillary buds, organogenesis through callus culture or adventitious bud induction, and somatic embryogenesis. In Korea Forest Research Institute (KFRI), the first tissue culture trial in woody plant was initiated from the bud culture of hybrid poplars (Populus alba x P. glandulosa) in 1978. Since then several mass propagation techniques have developed from conifer and hardwood species, resulting in allowing practical application to Poplars, Birches and some oak species. In addition, useful micropropagation and genetic resources conservation techniques were established in some rare and endangered tree species including Abeliophyllum distichum. Among various in vitro propagation techniques, somatic embryogenesis is known to be the most efficient plant regeneration system. Since the first somatic embryo induction was reported in Tilia amurensis by KFRI in 1986, various protocols for direct or indirect somatic embryogenesis systems have developed in conifer and hardwood species including Larix leptolepis, Pinus rigida x P. taeda F1, Kalopanax septemlobus and Liliodendron tulipifera, etc. However, most of these technologies have been developed using juvenile tissues, i.e. immature zygotic embryos or mature embryos. Therefore it has been difficult to directly application to tree breeding program due to their unproven genetic background. Recently remarkable progresses and new approaches have been achieved in mature tree somatic embryogenesis. In this article we reviewed several micropropagation techniques, which have been mainly developed by KFRI and recent international progresses.