• Journal of Plant Biology
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• v.6 no.2
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• pp.3-6
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• 1963

As a part of embryological studies of Panax ginseng, megasporangium and megagametophyte formations were investigated. Ovule is found to be auatropous. Small-sized nucellus is surrounded by thick layered single integument. As the embryo sac develops, the nucellus along with some parts of the inner epidermis of integument disintegrates and completely disappers at flowering stage. Embryo sac takes the type of typical Polygonum although antipodal cells disappear and polar nuclei fuse to form secondary nucleus before fertilization. Mature embryo sac consists of egg apparatus and large secondary nucleus lying adjacent to the egg. Besides the normal ovule, tiny incomplete ovule develops near the base of style. Frequently two normal ovules are formed in a single locule. Chromosome number counted is PMC is n=24.

• Journal of Plant Biology
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• v.6 no.1
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• pp.1-7
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• 1963

Two individuals of intergeneric hybrids in the crossing of Brassica pekinensis ♀$\times$Raphanus sativus ♂ were obtained, and among the three kinds of plants, Brassica, Raphanus, and F1, comparison on the mega- and microsporogenesis, megagammetophyte formation, and morphological changes in the developing sporangia, etc., were made. Differences between Brassica and Raphanus were observed in the shape of mega- and microsporangia, their changes in development, and the formation of megagametophyte. Sporangia of the F1 plants, until pre-meiotic stage, show intermediate, maternal, paternal, or vigorous inclination, and the difference of these characteristics when compared with those of the parent is slight. Meiotic irregularity resulted from the intergeneric hybridity of F1 plant gives rise to the abnormal mega- and microspore and accompanied abortive female and male gametophytes, bringing about the remarkable differences from its parent in the morphological changes of the developing mega- and microsporangia.

• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.330-337
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• 1987

Megagametophyte tissues from seeds of 45 loblolly pine clones were subjected to horizontal starch-gel electrophoresis. The resulting gels were tested for activity of five enzyme systems (GOT, SDH, PGM, MDH, and AP). Isozymes observed were under control of 11 loci. All 45 clones could be identified with unique genotypes at above 10 loci.

• Journal of Korean Society of Forest Science
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• v.68 no.1
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• pp.32-36
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• 1985

Megagametophyte tissues of Pinus densiflora were subjected to study the inheritance of acid phosphatase (ACP), alcohol dehydrogenase (ADH) and catalase (CAT) isozymes by starch gel zone-electrophoresis. At least three or four zones were segregated for ACP isozyme. However, as one isozyme of ACP-A zone was separated clearly, only that isozyme was analysed. Five isozyme phenotypes (A1-A5), observed in ACP-A zone, were segregated to a simple Mendelian ratio, suggesting that these are controlled by five codominant alleles existed at ACP-A locus. Two zones of activity were segregated in the gels after staining for ADH, the more anodal zone (ADH-A) of the two was invariant in our materials. Three isozyme phenotypes (B1-B3) were observed in ADH-B zone and these variants showed a 1:1 segregation pattern, suggesting that each variant is controlled by three codominant alleles at ADH-B locus. A total of five isozyme phenotypes, composed of multiple bands, were observed in CAT isozyme. The segregation of these phenotypes in heterozygous trees did not show any significant deviation from a 1:1 segregation. Therefore, the genetic control of CAT isozyme in Pinus densiflora seeds seems to be based on a single locus (CAT-A) with Five codominant alleles ($A_1-A_5$).

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.422-428
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• 1998

Polymerase chain reaction(PCR)-based inter-simple sequence repeats(I-SSR) markers were analyzed in 48 megagametophytes of a single tree of Abies koreana $W_{ILS}$. Nineteen of the 35 primers, screened with 6 megagametophyte DNA and produced the clearest amplification products in the preliminary experiment, were used for PCR with 48 megagametophyte DNAs sampled from a single tree. On the basis of the chi-square test, a total of 51 amplicons, amplified by the 19 primers, were revealed to be segregated according to the Mendelian ratio(i.e., 1 : 1 segregation ratio) in the 48 megagametophytes at 5% significance level. Based on the linkage analysis, the observed 51 Mendelian loci turned out to be unlinked each other, which suggested that they are evenly distributed in the genome. However, majority of RAPD markers are known to belong to the independent linkage blocks, which frequently results in the amplification of RAPD markers from the restricted regions of the genome. Owing to the nature of even distribution of the 51 loci observed in this study, the I-SSR markers could give better resolution of estimating genetic diversity from the whole genome than RAPD markers. And I-SSR markers are also more suitable than RAPD markers for reconstructing phylogenetic relationship by a cladistic method which requires to fulfil the assumption of independent evolution of the different characters.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.242-247
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• 1989

This study was conducted to estimate the inheritance of allozyme variants in IDH, ME and PGI, using megagametophyte tissue of seeds of Pinus densiflora and Pinus thunbergii in Kyungpook province. Two alleles at a single locus were detected for MH in Pinus densiflora, but Pinus thunbergii showed no varition, showing only one band. Four alleles at one locus were determined for ME in Pinus densiflora and Pinus thunbergii. Two loci were found for PGI and no variation seemed to occurred in A-locus as the presence of one single band. Five alleles were presented in B-locus in Pinus densiflora, but two alleles $B_1$ and $B_2$ in Pinus thunbergii. In PGI, an allozyme composed of multiple bands is observed from haploid megagamtophyte tissues. The isozyme variants of IDH, ME and PGI were appeared to segregate into 1 : 1 ratio for all zones.

• Molecules and Cells
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• v.20 no.2
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• pp.201-209
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• 2005

We have constructed an AFLP-based linkage map of Japanese red pine (Pinus densiflora Siebold et Zucc.) using haploid DNA samples of 96 megagametophytes from a single maternal tree, selection clone Kyungbuk 4. Twenty-eight primer pairs generated a total of 5,780 AFLP fragments. Five hundreds and thirteen fragments were verified as genetic markers with two alleles by their Mendelian segregation. At the linkage criteria LOD 4.0 and maximum recombination fraction 0.25(${\theta}$), a total of 152 markers constituted 25 framework maps for 19 major linkage groups. The maps spanned a total length of 2,341 cM with an average framework marker spacing of 18.4 cM. The estimated genome size was 2,662 cM. With an assumption of equal marker density, 82.2% of the estimated genome would be within 10 cM of one of the 230 linked markers, and 68.1% would be within 10 cM of one of the 152 framework markers. We evaluated map completeness in terms of LOD value, marker density, genome length, and map coverage. The resulting map will provide crucial information for future genomic studies of the Japanese red pine, in particular for QTL mapping of economically important breeding target traits.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.409-415
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• 1996

Isozyme variations in 4 enzyme systems in Pinus densiflora for. multicaulis in 31 individual trees collected throughout the country were studied by starch gel electrophoresis using haploid megagametophyte tissue to compare with those of Pinus densiflora. A minimum of 7 loci were found to code for isozymes of the enzyme systems. No variation was found at locus GOT-A; at the remaining 6 variable loci(GDH-A, GOT-B, GOT-C, IDH-A, LAP-,A, LAP-B) and 2 to 4 alleles were identified. We could not find any marker alleles to distinguish Pinus densiflora for. multicaulis from Pinus densiflora at the isozymes studied here. Allele frequency distributions at each loci were almost all the same as those of P. densiflora. The percentage of polymorphic loci(99% level), the number of alleles per locus, the observed and expected heterozygosities were 85.7, 2.3, 0.165 and 0.186%, respectively. The level of genetic diversity in Pinus densiflora for. multicaulis seemed to be less than that of P. densiflora.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.527-535
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• 2000

Isozyme variants of 15 enzyme systems were analyzed in megagametophytes of Ginkgo biloba L. Five enzyme systems (ADH, G6PD, IDH, MPI, and UGPP) appeared to be monomorphic. Only 11 isozyme zones observed in 10 enzyme systems were polymorphic : ACON-A, FST-B, GDH-A, GOT-B, MDH-B, MDH-C, MNR-A, PGI-B, PGM-A, 6PGD-B and SKDH-B. The segregation ratio and heterogeneity at most polymorphic zones suggested that each isozyme zone was controlled by a single locus with codominant alleles, but significant deviation from 1 : 1 segregation was observed at MDH-B in pooled data. Three pairs of isozyme loci (ACON-A : MDH-B, GOT-B : PGI-B, and MNR-A : SKDH-B) were found to be weakly linked. Recombination frequencies between them ranged from 0.38 to 0.40 (p<0.05).

• Journal of Korean Society of Forest Science
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• v.58 no.1
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• pp.1-7
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• 1982

Megagametophyte and embryo tissue of Pinus densiflora were subjected to study the inheritance of glutamate-oxalate transaminase(GOT) and leucine aminopeptidase(LAP), and linkage relationship among isozyme loci coding both enzymes by starch gel zone-electrophoresis. Four zones of activity were observed for GOT. No variation was found in the fastest migrating zone (GOT-A). Electrophoretic phenotypes of the other two zones (GOT-B and GOT-C) showed 1:1 segregation ration, suggesting that each zone is controlled by a single locus. Foru and three alleles were identified at both loci respectively. The isozyme pattern of the fourth zone(GOT-D), migrated cathodally, coincided precisely with that of GOT-C. Whether the two zones are controlled by the same locus or by two tightly linked loci remained unknown. In all three variant GOT zones, heterozygoes embryos produced triple band patterns, indicating that GOT isozyme in Pinus densiflora is a dimer. Two zones of activity stained for LAP were found. The segregation of the two zones (LAP-A and LAP-B) suggested that tow loci control each of both isozymes. Two and three alleles were identified at both loci. GOT-B and LAP-B were found to be tightly linked, showing an average recombination frequency of 12.5 percent. Slight deviation from independent assortment was observed between GOT-B and GOT-C, with recombination frequency of 41 percent.