• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.13-17
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• 1995

In order to induce haploid plant through pollen culture, pollens of Paeonia albiflora were cultured on MS liquid medium The development of micospore through pollen culture was examined The effect of low temperature (5$^{\circ}C$, 10 days) pretreatment on callus induction and embryogenesis in pollen culture was not evident Calli derived from pollen gave rise to globular embryos when transferred onto solid medium containing 0.5 mg/, 2,4-L. The effect of low temperature pretreatment and medium. combination to pollen viability was unrecognized. Pollen viability was reduced as the culture proceeded.

• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.411-413
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• 2000

The ability of microspores or young pollen grains (male gametophytes) to undergo developmetal switch to embryogenic (sporophytic) pathway exemplifies the concept of totipotency as applied to haploid posmeiotic cells. As a first step pollen is devoid of positional information provided in situ by the intact anther - by isolation and cultivation in vitro in artificial media. This is inevitably accompanied by some degree of stress response in microspore/pollen. It has been shown in both monocots and dicots that intentional stress treatment (mostly starvation or heat shock) greatly stimulates embryo induction rate. Using transgenic sHSP antisense Nicotiana tabacum we show that expression of small heat shock proteins is an integral part of successful embryo and later haploid plant production from pollen grains. Our recently published data show that sHSP chaperone function is optimal in the absence of ATP.

• Current Research on Agriculture and Life Sciences
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• v.31 no.2
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• pp.75-82
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• 2013

Haploids are plants with a gametophytic number of chromosomes in their sporophytes. Androgenesis occurs from asymmetric division of pollen grains into generative cells and vegetative cells, followed by re-entry of the vegetative cell during S-phase, which causes microspores progress into G2/M transition in culture. One of the most interesting features of haploids is the possibility to produce doubled haploid (DH) individuals. Doubled haploidy is extremely useful to plant breeders because it enables shortened breeding periods and efficiency in selection of useful recessive agronomic traits. Doubled-haploid technology is not only applicable to breeding, but also to transformation programs of desired genes. In addition to practical breeding programs, DH lines provide useful materials of fundamental genetics including exploitation of QTLs and genes conferred with various agronomic traits by establishing DH populations. This paper provides historical overviews on androgenesis and describes several mechanisms associated with pollen embryogenesis, including mode of actions in pollen embryogenesis, mechanisms of chromosome doubling and factors affecting androgenesis. We also discuss recent progress in application of haploids to breeding, genes associated with in vitro response and drawbacks to anther culture for application of doubled haploids in crop breeding.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.51-55
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• 1994

Pollen microspores isolated from peony anthers were cultured by agarose embedding method in the MS medium with 2,4-D(1mg/l) or phenylacetic acid(1, 10, 100mg/l), and without plant hormone. It was observed that pollen microspores cultured on hormone-free medium were directly developed into embryos. Callus formation was enhanced from microspores which were cultured on medium supplemented with 1mg/l PAA. Embryos were also formed from the calli transferred into the hormone-free medium.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.251-256
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• 2005

Cytokinins are essential plant hormones that play crucial roles in various aspects of plant growth and development. To better understand the molecular mechanisms of cytokinin action, we identified cytokinin related proteins by a proteomic approach. Proteins extracted from control and trans-zeatin treated Arabidopsis seedlings were separated and analyzed by two dimensional gel analysis. Differentially expressed protein spots were identified with peptide mass fingerprinting based on matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and database searching, We obtained ten up-regulated and one down-regulated proteins upon t-zeatin treatment. The expression of the following proteins was induced; pollen allergen like protein, L-ascorbate peroxidase, tetrapyrrole methylase family protein, SGT1 protein homolog, disease resistance related protein, maternal embryogenesis control protein, paxneb related protein, gluthathione S-transferase and IAA amino acid hydrolase homolog.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.165-168
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• 1995

The embryos formed from anther culture of peony exhibited divergent morphologies. The frequency of normal embryos with two cotyledons was about two times higher in the embryos formed through direct embryogenesis than those formed from callus. About 69% of the embryos with two cotyledons converted into normal plants, but convention rate of the abnormal embryos with one and three or four cotyledons was only 4 to 9%. The embryos of hem and bowling pin shape did not undergo development into normal plants.

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.193-198
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• 2002

The objective of this study was to determine the effects of phenylacetic acid (PAA) on embryo production in anther and microspore culture of herbaceous peony (Paeonia lactiflora Pall.). The anthers of herbaceous peony were cultured on MS medium with 0 to 100 mg/L PAA according to two-step culture method. The ruptured anthers were transferred onto embryo formation medium without growth regulators. The MS medium with 2 mg/L PAA was effective in enhancing of direct embryogenesis and producing of normal embryo with two cotyledons from the cultured anthers. However, the increase of PAA concentration more than 5 mg/L PAA inhibited the embryo formation and promoted to callus formation from the anthers. The PAA affects significantly on the division of microspore and embryo formation in shed pollen culture and the best result was obtained from a medium supplement with 2 mg/L PAA. The preculture of anther for 10 days on solid medium with 2 mg/L PAA was effective for embryo formation from shed microspore of herbaceous peony.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.129-142
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• 1986

Fifty-five local collections of buck wheat, Fagopyrum esculentum, were investigated their ratios of long-styled (LS) and short-styled (SS) flowers, fertility, meiosis of megaspore and microspore mother cell, female and male gametogenesis, and egg apparatus in accordance with the sowing seasons (spring, summer), altitudes (20m, 50-100m, 300m), and parent style types (L, S). Also they were embryologically investigated the fertility, fertilizing phenomenon and proembryogenesis by the legitimate and illegitimate pollination. There were no differences in the ratios of long-styled and short-5tyled flowers along with altitudes, but more irregularness was observed in plain area than that in the mountaineous or coastal area. LS versus SS ratios by sowing seasons were significantly separated into 1 : 1 in the summer sowing (P 0.1), but they were irregularly separated in the spring sowing. The segregating ratios by parent style types showed more number of short-styled flower in the spring sowing, and were statistically seperated into 1 : 1 in the summer sowing (P 0.25), regardless to parent style types. In the artificial legitimate union, the seed setting rates of the summer sowing (59-61%) were much higher than those of the spring sowing (about 30%), but in the artificial illegitimate union the seed setting rates were only fructified about 0.8-1.8% in the spring sowing. The seed setting rates in accordance with flowering stages were larger in turn early, middle, late, in the summer sowing. The grain number and grain weight per plant of short-styled flower were more than those of long-styled one regardless to style types. The 1,000 grain weight of long-styled flower was heavier than that of short-styled one in large grain, but it was lighter than that of short-styled flower in small or medium grain. The percentage of normal female and male gametogenesis in the summer sowing were higher than those in the spring sowing. The ovule was atropous and two polar nuclei were a synkarion before flowering. The pollens germinated at 30 minuts after pollination and the pollen tube grew continually and penetrated into micropyle at 1.5-2 hours and the two male nuclei fertilized with egg nucleus at 3 -5 hours after pollination. Flertilizing times in summer were shorter than in autumn. The fertilized egg was divided in a small apical cell toward the interior of the embryo sac and a large basal cell toward the micropyle cell at 15-24 hours after pollination, and division times in summer were shorter than in autumn. The proembryo began the embryogenesis at 7-8 days and formed itself into the perfect embryo at 15 days after pollination.