• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.429-438
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• 2007

Early growth vigor(EGV) is one of the physiological characteristics that may contribute to the increase of genetic yield potential and radiation use efficiency by closing the canopy earlier. To estimate the genotypic variation of EGV, determine the relationships among the related traits, and identify the rapidly growing genotypes and indirect indicator for selection in breeding program, the evaluation of EGV and EGV-related traits was conducted for a total of 140 rice varieties consisting of 101 Korean, 25 Northern China and 14 IRRI-bred rice varieties in a serial sowing experiment in plastic rain shelter and plastic-covered nursery bed in 2003. EGV defined as the amount of leaf area and/or dry weight produced early in the season and the EGV-related traits such as length and breadth of the $2^{nd}\;and\;3^{rd}$ leaves showed highly significant positive correlation with the embryo and seed weight. Especially, the genotypic variation in the length of the third leaf was explained over 90% of genotypic variation in the seed weight. Owing to a large effect of seed size on EGV and its related traits, vigor measurements were adjusted based on their linear or exponential relationships with seed weight for excluding the seed weight effect. EGV and its related-traits adjusted for seed weight also showed big variation among genotypes. Increased EGV was genetically correlated with increases in breadth and length of early leaves. The broad-sense heritability for EGV was significantly high(81%), but lower than those of leaf breadth(90% for the $2^{nd}$ leaf and 93% for the $3^{rd}$ leaf) and length(87% for the $2^{nd}$ leaf and 89% for the $3^{rd}$ leaf). Significantly positive genetic correlations were found between EGV and the breadth and length of early leaves. The high heritability of early leaf breadth and length coupled with their strong genetic correlation with EGV indicated that the breadth and length of the $2^{nd}\;and\;3^{rd}$ leaf would be used as good indirect indicators for EGV selection in rice breeding program.

• Applied Microscopy
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• v.38 no.4
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• pp.307-314
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• 2008

Hydrophytes such as Spirodela polyrhiza form dormant turions to withstand cold winters. The turion is an anatomically distinct structure from which a vegetative frond arises later during germination. The turions sink to the bottom of the pond when temperatures drop and remain there throughout the winter. In the spring, they float to the surface and germinate into a new frond from the turion primordium. Unlike fronds, turions are known to possess small aerenchyma, starch grains, and relatively dense cytoplasm. These features allow the turions to survive the cold winter season at the bottom of the pond. Spirodela polyrhiza has been investigated previously to a great extent, especially in its physiological, biochemical and ecological attributes. However, a little is known about the structural features of the frond and turion during turion development. Thus, the aim of the present study was to reveal the structural characteristics of the frond and turion with regard to tissue differentiation, aerenchyma development, starch distribution, and ultrastructure, with the use of electron microscopy. A moderate degree of mesophyll tissue differentiation was found in the frond, whereas the turion did not exhibit such differentiation. Within the frond tissue, approximately $37{\sim}45%$ of the cellular volume was occupied by a large aerenchyma, but only $9{\sim}15%$ was taken up by the aerenchyma in the turion. The turion cells, especially those of the turion primordium, were derived from frond cells, and contained cytoplasm. Their cytoplasm was densely packed with plastids, mitochondria, endoplasmic reticulum, Golgi bodies, and microtubules. Plasmodesmata were also well developed within these cells. The most striking feature observed was the distribution of starch grains within the plastids of turion cells. Before the turion sank to the bottom of the pond, a considerable amount of starch accumulated in the plastid stroma. The starch grains dissolved when temperatures rose in the spring, and this promptly provided the nutrients which the primordium needed for turion germination. The turion therefore, was an appropriate dormant structure for free-floating, reduced hydrophytes like Spirodela polyhriza due to its small aerenchyma and large starch grains that aided in the purpose of sinking below the surface of the water to survive cold winters. The new fronds that arose from such turions grew rapidly in the spring, beginning the new life cycle.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.345-356
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• 2012

We investigated the changes of fruit quality parameters, polysaccharide contents and cell wall components during maturation and ripening of two Korean pear cultivar 'Hanareum' and 'Manpungbae' compared with 'Niitaka' pear (Pyrus pyrifolia Nakai) which showed different physiological maturity based on days after full bloom (DAFB). Flesh firmness decreased continuously with fruit development and maturation, reaching a final level of 29.4, 33.5, and 27.4N at maturity in 'Hanareum' (127 DAFB), 'Manpungbae' (163 DAFB), and 'Niitaka' (170 DAFB), respectively. The level of ethylene production was very low in early season 'Hanareum' pear which showed at most 0.39 ${\mu}L{\cdot}L^{-1}$ at maturity and no ethylene was detected in 'Manpungbae' and 'Niitaka' at maturity. Fructose was the most abundant soluble sugar during fruit maturation in the pears tested and an increase of sucrose was observed during fruit ripening in the Asian pears commonly. Ethanol insoluble solids (EIS) content decreased gradually with different levels among the pear cultivars as fruit ripens consisted of 10.79, 12.72, and 12.75 $mg{\cdot}g^{-1}$ FW. The amount of total soluble polyuronides was higher in early season cultivars 'Hanareum' than those of mid-season cultivar 'Manpungbae' and 'Niitaka'. In 'Niitaka' which harvested most late season, the level of 4% KOH soluble hemicelluloses was lower than 'Hanareum' and 'Manpungbae' and maintained constantly during fruit ripening period. Cellulosic residues were determined high level in 'Niitaka' which showed 612.33 ${\mu}g{\cdot}mg^{-1}$ EIS at maturity when compared with 'Hanareum' (408.0 ${\mu}g{\cdot}mg^{-1}$ EIS) and 'Manpungbae' (538.67 ${\mu}g{\cdot}mg^{-1}$ EIS). The main constituents of cell wall neutral sugars which consisted of arabinose, xylose, galactose, and glucose were decreased gradually with onset of fruit ripening regardless of cultivar. Arabinose which was predominant in 'Hanareum' pear decreased at the last stage of ripening, but the changes of cell wall neutral sugar during ripening were not occurred in 'Niitaka' pear. The change of molecular mass distribution in water soluble pectin observed dominantly at the early stage of fruit development. Depolymerization of 4% KOH-soluble hemicelluloses and degradation of xyloglucan showed in early-season cultivar 'Hanareum' during fruit maturation, and degradation of those fractions were detected only at the early stage fruit development in mid-season cultivar 'Manpungbae' and 'Niitaka'. The molecular mass profile of CDTA soluble pectin, $Na_2CO_3$-SP and 24% KOH soluble hemicelluloses showed no significant change during fruit maturation regardless of cultivar.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.163-169
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• 2013

Cryopreservation of poultry semen has been reported, but preservation of female genetic material has not been possible because of the unique anatomical and physiological characteristics of the avian egg. Thus an alternative strategy for conservation of oviparous species of animals must be developed. Recent technological developments for producing germline chimeras by the transfer of primordial germ cells (PGCs) into recipient embryos has enabled the conservation and retrieval of chicken genetic resources in their complete form. In the present study, fertilized eggs were incubated for about 5.5 days to obtain embryos at stage 28. The whole embryo was collected from the germinal gonad using a fine glass micro pipette under a microscope. The PGCs were then purified using MACS method. Two commercially available cryoprotectants (A and B) were used to preserve the PGCs, and EG were used as a control. The average recovery rate of PGCs after thawing was 35.5% and 60.5% with the A and B treatments, respectively. There was no significant difference between B treatments and control, which showed an average recovery rate of 52.8%. However, the recovery rate obtained using A cryoprotectant (35.5%) was significantly lower than using treatment control and B. The average viability of the PGCs after thawing were 77.9% and 77.4% for cryoprotectants A and B, respectively, and the control were was 81.6%. There was no statistically significant difference between the two treatments and control. It was concluded that all of the available cryoprotectants examined in this study could be used for preservation of PGCs from embryos. Further experiments to produce germline chimera from PGCs preserved using this techniques are strongly recommended.

• Journal of Life Science
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• v.23 no.3
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• pp.415-425
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• 2013

This study compared the characteristics of five Bacillus strains capable of aerobic and anaerobic growth, CBW3, CBW4, CBW9, CBW14 and EBW10. They were isolated and selected from a polychaete, Perinereis aibuhitensis, which is known as a good degrader of organic compounds in marine wetland. Based on a 16S rRNA sequence, CBW3 and CBW14 were found to share more than 99.8% similarity with B. nanhaiensis, B. arsenicus and B. barbaricus. CBW4, CBW9 and EBW10 shared 92.7%, 99.8%, and 99.8% similarity with B. anthracis, B. algicoa and B. thuringiensis, respectively. The temperature, salinity, and pH ranges of the cell growth of the Bacillus strains were $4-45^{\circ}C$, 0-17%, and pH 5-pH 9, respectively. All Bacillus strains were found to exhibit enzyme activities for the degradation of casein and starch. Notably, strain EBW10 exhibited the enzyme activities for all the tested macromolecules, DNA, casein, starch, cellulose, and four kinds of Tweens, which suggests the possibility that it had protease, amylase, cellulose, and lipase. All five Bacillus strains had alkaline phosphatase activities, and the strains CBW3, CBW4, and EBW10 also had acid phospatase. Strains CBW3 and EBW10 exhibited the enzyme activities both for esterase (C4) and esterase lipase (C8). The analysis of fatty acids revealed that in all strains, major fatty acids were anteiso $C_{15:0}$ and iso $C_{15:0}$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.3
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• pp.108-118
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• 2012

To investigate the responses of yellow poplar (Liriodendron tulipifera L.) seedlings to the interactive effects of the elevated atmospheric $CO_2$ level and nitrogen addition, we measured biomass, photosynthetic pigments, photosynthesis, and the contents of nitrogen (N) and carbon (C) from the seedlings after 16 weeks of the treatments. Yellow poplar seedlings were grown under the ambient ($400{\mu}mol\;mol^{-1}$) and the elevated (560 and $720{\mu}mol\;mol^{-1}$) CO2 concentratoins with three different N addition levels (1.2, 2.4, and $3.6g\;kg^{-1}$) in the Open Top Chambers (OTC). The dry weight of the seedlings enhanced with the increased N levels under the elevated $CO_2$ concentrations and the increment of the dry weight differed among the different N levels. Photosynthetic pigment content of the yellow poplar leaves also increased with the increase of the $CO_2$ concentration levels. The effects of the N levels on the photosynthetic pigment content, however, were significantly different among the $CO_2$ levels. Photosynthetic rates were affected by the levels of $CO_2$ and N concentrations. Stomatal conductance and transpiration rates increased with increasing $CO_2$ concentration. The carboxylation efficiency of the seedlings without N addition increased under the higher $CO_2$ concentrations whereas that with N addition decreased under the elevated $CO_2$ concentrations. Nitrogen and carbon uptake in leaf, stem, and root increased with the elevated $CO_2$ concentration level and N addition. In conclusion, under the elevated $CO_2$ concentrations, physiological characteristics and carbon uptake of the yellow poplar seedling were improved and increased with N addition.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.765-772
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• 2004

Cooking condition of Tarakjuk (milk-rice porridge) was established based on gelatinization temperature using differential scanning calorimetry (DSC) of roasted Ilpum rice flour, which has highest enzyme-resistant starch (RS) content. Effect of cooking temperature and time on DSC characteristics, crystallity with X ray diffractogram, RS content, in vitro starch digestibility (IVSD), amino acid composition, and in vitro protein digestibility (IVPD) of Tarakjuk were determined. Tarakjuk was cooked at 50, 56.5, 64, and $69^{\circ}C$ for various durations. Rice flour ingredient used was Ilpum, previously roasted at $185^{\circ}C$ for 25 min. Tarakjuk cooked at 50 and $56.5^{\circ}C$ showed two thermal transitions between $63.7-125.2^{\circ}C$ as determined by DSC, corresponding to endotherms of starch gelatinization $(63.7-73.8^{\circ}C)$ and melting of amylose-lipid complex (AM-lipid complex, $97.7-125.2^{\circ}C$), whereas that cooked at 64 and $69^{\circ}C$ showed only AM-lipid complex melting transition between $96.9-127.6^{\circ}C$. As cooking temperature increased, RS content of Tarakjuk decreased, whereas IVSD increased. Total amino acid content was between 11,558-15,601mg/100g, depending on cooking condition used. Compared with conventionally made control, contents of essential amino acids, such as lysine and tryptophane, were higher at 50 and $56.5^{\circ}C$, and IVPD showed higher increase. Results reveal degree of gelatinization in Tarakjuk with high RS content as well as low IVSD and high IVPD, which are important from physiological and nutritional point of view, can be produced by controlling cooking condition.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.65-75
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• 2002

The study was carried out to determine the growth and biomass production of major deciduous trees including Betula platyphylla var. japonica, Betula schmidtii, Zelkova serrata, Acer mono, Prunes sargentii, and Ligustrum obtusifolium subjected to artificial shade treatment in nursery field. The six deciduous trees seedlings grow for 2 years under different light intensity of 100%, 38-62%, 22-28%, 7-20%, and 2-6% of the full sun light intensity. The results were as follows; In the seedling heights and root collar diameters of shade intolerant species like Betula platyphylla var. japonica and Betula schmidtii, the relative growth rates of seedlings grown in full sun showed 2 times as compared with those subjected to the shade treatment of 2-6% light intensities of full sun. In the shade tolerant species like Acer mono ant Ligustrum obtusifolium, the growth performances were better in the seedlings grown in 38-62% light intensities of full sun. Total dry mass including the dry mass of leaves, shoot and root were as a whole decreased with shade treatment. The ratio of the dry mass of leaves and stem increased the dry mass of root. T/R ratio of the seedlings increased by decreasing the relative light intensity. And the T/R ratio of 2-6% light intensities of full sun was ranged from 1.1~5.0 were greater in the full sun light was ranged from 0.6~3.2. Light intensity by artificial shade treatment decreased in deciduous trees when compared on the whole, it showed tendency that SLA increases, increased that seeing resemblant tendency in LAR and LWR and changed of light intensity is strong, it increased that showed difference as statistical. But, LWR of Betula platyphylla var. japonica increased gradually and showed tendency that decreases rapidly in the shade treatment of 2-6% light intensities of full sun. This result is thought that biomass production decreased by shading treatment influenced in physiological characteristics such as leaf area and decrease of the leaf amount.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.411-417
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• 2009

This research is intended to discover physiological and biochemical defense mechanisms against herbivores of 8 species of the genus Acerby examining the morphological characteristics of the leaf, the structure and number of leaf domatia, herbivores insects and mites feeding on leaves, which were collected from the trees growing in Mt. Chiak, Mt. Cheongtae, Mt. Jungwang, Mt. Bangtae, Mt. Taebaek and Wonju City. This research was conducted from May through July, 2009, and the results are as follows. The domatia of A. pseudosieboldianum, A. pictum subsp. mono and A. mandshuricum belongs to tuft type; that of A. palmatum, A. triflorum and A. tschonoskii pocket+tuft type; and that of A. tegmentosum pocket type. The number of domatia per leaf turned out to be the highest in the case of A. tegmentosum(20.2), and the lowest in the case of A. ginnala (4.2). Leaf surface trichomes of A. palmatum, A. pseudosiebotdianum, A. ginnala and A. mandshuricum are covered with villi; those of A. pictum subsp. mono and A. triflorum with soft, pilose type of hair, and those of A. tschonoskii with stiff, strigose hair. The trichome density of lower leaf surface is found to be higher than that of the upper leaf surface. Only in the case of A. palmatum, A. pseudosieboldianum, A. tegmentosum and A. tschonoskii, a small amount of nectar is found to be secreted from the distal vein parts of the leaf margin. The number of mites on each leaf are found to be significantly different among tree species, and average mites number per leaf was the highest in the case of A. tschonoskii (9.2/leaf), and A. mandshuricum, A. pseudosieboldianum, and A. triflorum follow it in decreasing order. Minute insects attacking the leaf of Acer spp. include Periphyllus californiensis, P. viridis, Psylla spp, and gall mites, and the number of these insects are found in Periphyllus californiensis, Psylla spp, P. viridis, and Cicadellidae sp. in decreasing order. The natural enemies of these herbivores insects are predatory mites, such as Chilocorus rubidus, Coccinella septempunctata and the nymph, Aphidius ervi, Poecilocoris lewisi and its larva, and Poecilocoris lewisi. Lasius japonicus and Formica japonica are symbiotic with aphids, and supports herbivores. Finally, our research confirmed that predatory mites attack Periphyllus californiensis and suck the body fluid of their victim. This proves that mites form a symbiotic relationship with plants through the mediation of leaf domatia. This also indicates that a protective mutualism may be more conspicuous in temperate broad-leaved trees.

• Sleep Medicine and Psychophysiology
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• v.13 no.2
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• pp.45-51
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• 2006

Obstructive sleep apnea (OSA) syndrome disrupts normal sleep. However, there were few studies to evaluate the asymmetric distribution, the one of the important factors of normal sleep in OSA subjects. We hypothesized that asymmetry would be broken in OSA patients. 49 male subjects with the complaint of heavy snoring were studied with polysomnography. We divided them into two groups based on the apnea-hypopnea index (AHI) fifteen: 13 simple snoring group (SSN, average AHI $5.9{\pm}4.4$) and 32 OSA group (average AHI $47.3{\pm}23.9$). We compared split sleep variables between the first half and the second half of sleep within each group with paired t-test for the evaluation of asymmetry. Changes of sleep architecture of OSA were higher stage 1 sleep% (S1), total arousal index (TAI), AHI, and mean heart rate (HR) and lower stage 2 sleep% (S2), REM sleep%, and mean arterial O2 saturation (SaO2) than SSN subjects. SWS and wake time after sleep onset (WASO) were not different between two groups. In split-night analysis, OSA subjects showed higher S2, slow wave sleep% (SWS), spontaneous arousal index (SAI), and mean HR in the first half, and higher REM sleep% and mean SaO2 in the second half. Those were same pattern as in SSN subjects. Mean apnea duration and longest apnea duration were higher in the second half only in the OSA. No differences of AHI, ODI, WASO, and S1 were found between the first and the second half of sleep in both groups. TAI was higher in the first half only in the SSN. SWS and WASO seemed to be influenced sensitively by simple snoring as well as OSA. Unlike our hypothesis, asymmetric distributions of major sleep architecture variables were preserved in OSA group. Losing asymmetry of TAI might be related to pathophysiology of OSA. We need more studies that include large number of subjects in the future.