• Journal of Plant Biology
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• v.36 no.3
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• pp.241-249
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• 1993

The pattern of RNA synthesis during male gametogenesis of Brassica napus was studied using 3H-uridine autoradiography. No incorporation of isotope occurred in the newly released microspore and the nonvacuolate, furrowed microspore. Peak incorporation of label during male gametogenesis occurred in the uninucleate, furrowed microspores showing various degrees of vacuolation. In this microspore stage, silver grains were localized in the nucleus and cytoplasm. Moderate incorporation of the isotope occurred in the nulceus of the vacuolated microspore. After the microspore mitosis, isotope incorporation occurred predominantly in the nucleus of the vegetative cell with little or no incorporation in the generative cell. In tricellular pollen, no incorporation of isotope was observed in both the vegetative nucleus and the sperms. Silver grains almost completely disappeared from tricellular mature pollen grains ready to germinate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.394-406
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• 1991

It was proved that cold tolerance of rice plants at the young microspore stage was affected by water temperature and nitrogen application from the spikelet differentiation stage to the young microspore stage, and this mechanism could be explained in the point of view of pollen developmental physiology. The cold tolerance of rice plants at the young microspore stage was severely affected by water temperature (Previous water temperature) and nitrogen application(Previous nitrogen application) from the spikelet differentiation stage to the spikelet differentiation stage. Although the duration is only 10 days or so from the spikelet differentiation stage to the young microspore stage, these days are very important period to confirm the cold tolerance of rice plants at the young microspore stage. The higher previous water temperature up to $25^{\circ}C$ and the deeper previous water depth up to 10cm caused the more cold tolerance of rice plants. Water irrigation of 10cm before the cretical stage showed lower cool injury than that of water irrigation of 20cm during the critical stage. The preventive effect of cool injury by combined treatment of the deep water irrigation before and during the critical stage was not additive but synergistic. The cold tolerance of rice plants grown in previous heavy nitrogen level was rapidly decreased when nitrogen content of leaf blade at the young microspore stage was excessive over the critical nitrogen level. Nitrogen content of leaf blade at the changing point of cold tolerance was estimated as about 3.5% for Japonica cultivars and about 2.5% for Indica x Japonica cultuvars. It is considered that these critical nitrogen contents of leaf blade can be used as a index of the safe critical nitrogen level for the preventive practices to cool injury. It was summarized that increase of engorged pollens per anther by high previous water temperature resulted from the increase of number of differentiated microspores per anther, otherwise, the increase of engorged pollens by the decrease of previous nitrogen level was caused by the decrease of the number of aborted microspores per anther.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.85-97
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• 1974

In order to clarify the inducing conditions and cause of sterility in rice plants, 4 varieties were cooled at 3 different levels of temperature combined with 3 different levels of treatment period. And 19 varieties were tested to examine the varietal difference of cold resistance. The results obtained were summarized as follows; 1. There were significant varietal differences in the effect of cooling treatment at meiotic stage. Suwon 213-1 was induced heavy sterility by 3 day cooling treatment at 17.5$^{\circ}C$ whereas Hayayuki, Nongpaik and Jinheung were induced a little sterility by 3 day cooling treatment at 15$^{\circ}C$ and 5 day treatment at 17.5$^{\circ}C$. The per cent of grain fertility was correlated significantly with the delayed days to heading, the degree of panicle extraction (Suwon 213-1, Nongpaik, Jinheung), culm length (Nongpaik, Suwon 213-1), and Auricle distance (Suwon 213-1). The degree of sterility was able to be estimated from the linear regression equation between the degree of panicle extraction (distance from panicle neck to flag leaf) and fertility percentage. In the case of heavy cold damage by the treatment of low temperature at meiotic stage, the rice plant had somewhat lower pollen density per anther, small and ununiform anther and pollen in size, and more sterile pollen grains. Suwon 213-1 showed anthesis in almost all spikelets, while Nongpaik, Jinheung and Hayayuki indicated considerable number of indehisced anther at 5 days after heading. 2. The fertility were not generally higher in cooling treatment at heading stage than at meiotic stage treatment. And significant correlation was found between the percentage of grain fertility treated at above two stages. Nongpaik and Jinheung were not affected in percentage of fertility by 5 day treatment at 15$^{\circ}C$ when these were treated at heading stage. Indehisced anthers were not found in Suwon 213-1 and Hayayuki, but Nongpaik and Jinheung showed more anthers which did not show anthesis 3. There was different varietal response to low temperature which was indicated by the decrease of grain fertility resulted from cooling treatment at meiotic stage. Jaekeun and Jinheung did not show low fertility but Milseong, Suwon 210, Satominoli and Suwon 213-1 showed outstanding decrease in fertility percentage by the cooling treatment at meiotic stage. The varieties which had low fertility were likely to have low pollen density per anther, abnormal anthers, small size po]]en grains and many sterile pollens. 4. Remarkable varietal difference of cold resistance was found in heading stage cooling treatment. Nongpaik, Jinheung, Jaekeun, Paltal, Akibare, Milseung and Palkeong were not affected in grain fertility by cooling treatments but Nonglimna No. 1, Suseong, Hayayuki, Suwon 213-1 and Suwon 210 showed significantly high sterility as treated by cool temperature. Most of the varieties showed higher fertility by cooling treatment at heading stage than meiotic stage but Hayayuki, Suseong and Nonglimna No.1 showed lower fertility when these were treated at heading stage than meiotic stage. There were two grops of varieties in the response to cooling treatment, one was somewhat non-anthesised and the other showed full anthesis. 5. In cold injury test of young seedlings, the result of observation was not accorded with the degree of growth inhibition. As a general, Palkeum and Suseong were highly torelant to cool temperature but Suwon 213-1, Jaekeun, Paltal, Shirogane, Palkeong, Mankyung were highly susceptible. 6. There is no significant correlation between the degree of young seedling cold damage and or the degree of growth retardation at seedling stage and grain fertility resulted from coding treatment both heading and meiotic stage.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.1-6
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• 1999

In order to obtain plantlet derived by anthers, the anthers of Lilium asiatic hybrid 'Gran Paradiso' were cultured on Murashige and Skoog's medium supplemented with various combinations of auxin and cytokinin. The most suitable pollen stage of anther culture for the callus induction was 3 days before anthesis at the early to late binucleate stage. Organogenic calli were induced on MS medium supplemented with 5.0 mg/L 2,4-D alone and the combination of 1.0 mg/L 2,4-D and 1.0 mg/L kinetin, however, the combination of NAA and BA was more effective than that of 2,4-D and kinetin on plant regeneration through organogenesis. Shoots were formed from the induced callus on the medium with 0.5 mg/L NAA and 1.0 mg/L BA after 180 days of culture. Multiple shoots with 3-4 leaves, roots, and bulblets were formed on the medium with the combination of 2.0 mg/L NAA and 2.0 mg/L BA after 250 days of culture. The chromosome from root tip of the regenerated plantlet showed the diploid (2n=2x=24). Diploid plants were transferred to the pots and all plants were flowered in two years.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.232-241
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• 1984

A series of experiments were carried out to know the effects of pollen stage, cold shock temperature and duration, and media for callus and green plant induction in rice anther culture. The results indicated that: (a) uninucleate stage of pollen was the most suitable stage for effective callus induction, (b) cold shock temperature of 8$^{\circ}C$ and 12$^{\circ}C$ was appeared to be proper temperature for callus induction, (c) callus induction rate was increased in the eight to 12 days long cold storage, (d) the medium N6 was better than that of N6D for callus induction, (e) green plant induction was better in both 4$^{\circ}C$ and 8$^{\circ}C$ than that of 12$^{\circ}C$ cold shock, (f) green plant frequency was higher in eight to 12 days long cold storage and (g) green plant frequency was doubled in the MS medium when compared with N6 medium.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.420-428
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• 2015

The majority of cultivated varieties of grape have perfect flowers that are clustered in an individual inflorescence. Grape flower has a single pistil, five stamens, a protective flower cap (calyptra), and a calyx. After fertilization, an individual flower develops into a single berry. Although there are a number of reported studies focusing on berry formation, berry enlargement, and sugar accumulation in grape, the morphological studies of flower, including gametophyte morphogenesis and structural change in floral organs, have not yet been studied in detail. In this study, we investigated the flower structure and development characteristics of grape using microscopy and defined the floral development stages 9 to 13 based on microspore or male gametophyte development stage from tetrad to mature pollen. We used seeded diploid table grapes 'Campbell Early' (Vitis labruscana) and 'Tamnara' (V. spp.) as plant materials. At floral development stage 9, pollen mother cells develop to tetrads. During floral development stages 10 to 11, unicellular microspore develop to mid bicellular pollen. At the end of floral stage 12, male gametophyte develops to mature tricelluar pollen. In floral stage 13, the flower cap falls off and flower bud opens. During floral development stages 9 to 12, there were no major changes in calyx length, whereas the length of the flower cap continuously increased. The flower cap-to-calyx length ratio was 2.0, 3.0, 4.5, and 6.5 at floral stages 9, 10, 11, and 12, respectively. The flower cap-to-calyx length ratio was consistent in the two grape cultivars, suggesting that the ratio is a morphological character representing floral development stage. This study provides a reference for determining floral development stage of the two grape cultivars. It will be useful for the determination of optimum time for microspore culture needed to generate doubled haploid lines and appropriate gibberellic acid treatment needed to induce parthenocarpic fruit development in 'Tamnara' grape.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.171-175
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• 1999

Morphological alteration of floral organ development in rice affected by chilling stress was examined. Three varieties of rice were grown under natural conditions and subjected to 12$^{\circ}C$ for 3 or 6 days starting from the ineffective tillering stage, before heading stage and returned to natural condition. Headings were delayed by a 6 day chilling treatment. After heading the panicles were collected and examined for any possible alteration in floral organ development. It appears that there were some differences in sensitivity to chilling stress and degree of injury depending on treatment stages and variety. Chuchungbyeo was the most frequent in producing abnormal flowers among the three varieties examined. Meiosis stage was shown to be the most vulnerable to chilling stress in both Chuchungbyeo and Ilpumbyeo and young panicle differentiation stage was the frequent stage to alter flower development in response to chilling stress only in Chuchungbyeo. It was confirmed that abnormalities occurred in pollen due to chilling stress is a major factor leading to low yield, but to some extent the alterations in carpel development may playa certain role in determining a total yield in response to chilling stress at the reproduction stage in rice. There were abnormalities like extra stigmata, extra lemma, double ovary as well as abnormal anther formation in response to chilling stress. Further studies of the phenocopy observed in rice floral development may be useful for an understanding of the resistance against chilling injury during reproductive stages in rice.

• Molecules and Cells
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• v.43 no.5
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• pp.448-458
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• 2020

T-DNA insertional mutations in Arabidopsis genes have conferred huge benefits to the research community, greatly facilitating gene function analyses. However, the insertion process can cause chromosomal rearrangements. Here, we show an example of a likely rearrangement following T-DNA insertion in the Anti-Silencing Function 1B (ASF1B) gene locus on Arabidopsis chromosome 5, so that the phenotype was not relevant to the gene of interest, ASF1B. ASF1 is a histone H3/H4 chaperone involved in chromatin remodeling in the sporophyte and during reproduction. Plants that were homozygous for mutant alleles asf1a or asf1b were developmentally normal. However, following self-fertilization of double heterozygotes (ASF1A/asf1a ASF1B/asf1b, hereafter AaBb), defects were visible in both male and female gametes. Half of the AaBb and aaBb ovules displayed arrested embryo sacs with functional megaspore identity. Similarly, half of the AaBb and aaBb pollen grains showed centromere defects, resulting in pollen abortion at the bi-cellular stage of the male gametophyte. However, inheritance of the mutant allele in a given gamete did not solely determine the abortion phenotype. Introducing functional ASF1B failed to rescue the AaBb- and aaBb-mediated abortion, suggesting that heterozygosity in the ASF1B gene causes gametophytic defects, rather than the loss of ASF1. The presence of reproductive defects in heterozygous mutants but not in homozygotes, and the characteristic all-or-nothing pollen viability within tetrads, were both indicative of commonly-observed T-DNA-mediated translocation activity for this allele. Our observations reinforce the importance of complementation tests in assigning gene function using reverse genetics.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.147-153
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• 1998

An investigation was conducted to ascertain the basic information on characteristics of growth and morphological characters among the Korean (Panax. ginseng), the American (Panax. quinquefolium) and the Bamboo (Panax. japonicus) ginseng. In aerial parts growth of the ginseng species by age, The Korean ginseng and American ginseng's stem and leaf growth was alike in 2-4 years old, but growth cycle changed in 6 years old. The Korean ginseng was more vigorous than the American ginseng. The Korean ginseng roots were highly observed in ratio of red skin roots among three species, whereas The American ginseng roots were highly infected by root rot. It seems to be variable depending on growing stage and species. The Korean ginseng flowered about the middle of May, the American ginseng early June, and the Bamboo ginseng was late of May, The berry color of the ginseng species was observed, The Korean and American ginseng's mature berry color was red, The Bamboo ginseng's berry was three type of color and shape. In root characteristics of the seedling, Korean (p. ginseng), American (p. quinquefolium) ginseng's root shape was similarity in type, the bamboo ginseng showed different type, which root length and root weight was smaller than those of ginseng. In morphological characters of Leaf surface, pollen, and stoma, the Korean ginseng and American ginseng had crystal rosette on epidermis cell, but the Bamboo ginseng didn't has crystal rosette. Pollen shape observed tricolpate pollen and size was media type among the ginseng species, and also guard cell was anomocytic type, which were observed by scanning electronic microscope.

• Plant Biotechnology Reports
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• v.1 no.1
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• pp.19-25
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• 2007

To develop an efficient screening method for detection of the transgene in Chinese cabbage (Brassica rapa spp. pekinensis) utilizing Basta spray, optimal conditions for Basta application were examined in this study. Two transgenic Chinese cabbage lines were obtained through Agrobacterium-mediated transformation and used as transgenic positive controls in the Basta screening experiment. Differential concentrations of glufosinate-ammonium were sprayed into three different growth stages of 12 commercial Chinese cabbage cultivars. The results showed that no plants could survive higher than 0.05% glufosinate-ammonium, and plants at the 2-3 leaf stage were most vulnerable to glufosinate-ammonium. On the other hand, no damage was observed in the transgenic control plants. Reliability of the Basta spray method was proven by showing perfect co-segregation of the tolerance to glufosinate-ammonium and the presence of the bar gene in T₁ segregating populations of the transgenic lines, as revealed by both PCR and Southern blot analyses. Using the developed Basta screening method, we tried to investigate the transgene flow through pollen dispersal, but failed to detect any transgene-containing non-transgenic Chinese cabbages whose parents had been planted adjacent to transgenic Chinese cabbages in field conditions. However, the transgene was successfully detected using Basta spray from the non-transgenic plants bearing the transgene introduced by hand-pollination. Since the Basta spray method developed in this study is easy to apply and economical, it will be a valuable tool for understanding the mechanism of gene flow through pollen transfer and for establishing a biosafety test protocol for genetically modified (GM) Chinese cabbage cultivars.