• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.10 no.2
• /
• pp.97-114
• /
• 1977

The fresh water prawn, Macrobrachium rosenbergi(de Man) is a very common species in Indopacific region, which inhaits both fresh and brackish water in low land area, most of rivers and especially aboundant in the lower reaches which are influenced by sea water. It is one of the largest and commercial species of genus Macrobrachium, which is commonly larger than $18\~21cm$ in body length, from the basis of eye-stalked to the distal of telson. As a part of the researches in order to investigate the possibilities on transplantation and propagation of this species, this work dealt with the problems on the effects of chlorinities upon zoeal larvae and post-larvae 1). metamorphosis rate and optimum chlorinity for metamorphosis to post-larve, 2). tolerance and comparative survival rate on various chlorinties, from fresh water to sea water $(19.38\%_{\circ}\;Cl)$, which reared for six days upon each stage of zoeal larvae, 3). accomodation rate on chlonities which reared for twelve days after transmigration into variant chlorinities of the range from $3.68\%_{\circ}$ Cl to $1.53\%_{\circ}$ Cl in the way of rearing of the range from $3.82\%_{\circ}$ Cl to $11.05\%_{\circ}$ upon each stage of zoea, 4). tolerance on both of fresh and sea water upon zoeal larva and post-larva under the condition of $28^{\circ}C{\pm}1$ in temperature and feeding on Artenia salina nauplii, 5). relationship between various chlorinities and grwth of post-larvae under the condition of $28^{\circ}C$ in tmperature and feeding on meat of clam. Thus these investigations were performed in order to grope for a comfortable method on seedmass production. Up to the present, the study on the effects of chlorinity upon earlier zoeal larvae and post-larvae of Macrobrachium species has been scarcely performed by workers with the exception of Lewis(1961) and Ling (1962,, 1967), even so their works were not so detailed. On the other hand, larvae of several species of this genus were reared at the water which mixed sea water so as to carry out complete metamorphosis to post-larva by workers in order to investigate on earlier 1 arval and earlier post-larval development, such as Macrobrachium lamerrei (Rajyalakshmi, 1961), M. rosenbergi and M. nipponense (Uno and Kwoa, 1969; Kwon and Uno, 1969), M. acanthurs (Choudhury, 1970; Dobkin, 1971), M. carcinus(Choudhury, 1970), M. formosense(Shokita, 1970), M. olfersii (Duggei et al., 1975), M. novaehallandiae (Greenwood et al., 1976), M. japonicum (Kwon, 1974) and M. lar (Shokita, personal communication), and there fore it is regarded that chlorinity is, generally, one of absolute factors to rear zoeal larvae of brackish species of Macrobrachium genus. Synthetic results on this work is summarized as the follwings: 1) Zoeal larvae required different chlorinities to grow according to each stage, and generally, it is regarded that optimum range of living and growing is from $7.63\%_{\circ}Cl\to\;7.63\%_{\circ}Cl$, and while differences of metamorphsis rate, from first zoea to post-larva, is rarely found in this range, and however it occurs apparently in both of situation at $7.63\%_{\circ}Cl$ below and $16.63\%_{\circ}Cl$ above and moreover, metamorphosis rate is delayed somewhat in case of lower chlorinity as compared with high chlorinity in these situations. 2) Accomodation in each chlorinity on the range, from fresh water to sea water, is different according to larval stages and while the best of it is, generally, on the range from $14.24\%_{\circ}Cl$ to $8.28\%_{\circ}Cl$ and favorite chlorinity of zoea have a tendency to remove from high chlorinity to lower chlorinity in order to advance larval age throughout all zoeal stages, setting a conversional stage for eighta zoea stage. 3) Optimum chlorinity of living and growth upon postlarvae is on the range of $4.25\%_{\circ}Cl$ below, and in proportion as approach to fresh water, growth rate is increased. 4) Post-large are able to live better in fresh water in comparison with zoeal larvae, which are only able to live within fifteen hours, and by contraries, post-larvae are merely able to live for one day as compared with ?미 larvar, which are able to live for six days more in sea water $19.38\%_{\circ}Cl\;above$. 5) Also, in case of transmigration into higher and lower chlorinities in the way of rearing in the initial chlorinities $ 3.82\%_{\circ}Cl,\;7.14%_{\circ}Cl\;and\;11.05%_{\circ}Cl$, accoodation rate is a follow: accomodation capacity in ease of removing into higher chlorinities from lower chlorinities is increased in proportion as earlier stages, setting a conversional stage for eighth zoea stage, and by contraries, in case of advanced stages from eighth zoea it is incraesed in proportion as approach to post-larva stage in the case of transmigration into lower chlorinity from higher chlorinity. On the other hand, it is interesting that in case of reciprocal transmigration between two different chlorinitiess, each survival rate is different, and in this case, also, its accomodation in each zoea stage has a tendency to vary according to larval stages as described above, setting a conversional stage for eighth zoea stage. 6) It is likely that expension of radish pigments on body surface is directly proportional to chlorinity during the period of zoea rearing, and therefore it seems like all body surfacts of zoea larvae be radish coloured in case of higher chlorinity. 7) By the differences that each zoeal larvae, postlarvae, juvaniles and adult prawn are required different chlorinity for inhabiting in each, it is regarded that this species migrats from up steam to near the estuary of the river which the prawns inhabits commonly in natural field for spawning and growth migration. 8) It had better maintainning chlorinities according to zoeal stage for a comfortable method on seed-mass production that earlier larva stages than eighth zoea are maintained on the range from $8\%_{\circ}Cl\;to\;12\%_{\circ}Cl$ to rear, and later larva stages than eighth zoea, by contraries, are gradually regula ted-to love chlorininity of the range from $7\%_{\circ}Cl\;to\;4\%_{\circ}Cl$ according to advance for post-larva stage.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.5 no.1
• /
• pp.45-52
• /
• 1985

Phytotron and field experiments were conducted to determine the influence of morphological development and environmental temperature on synthesis, translocation and accumulation behaviour of Fructosan, Monoand Disaccharose in corn cv. Blizzard and fodder sorghum cv. Sioux and Pioneer 931 at Munich technical university. Sorghum and maize plants were grown for 42 days at 4 temperature regimes (30/25, 25/20, 28/18 and 28/8 dog C) and mid-summer sunlight over 13-h days. The obtained results are summarized as follows: 1 Non-structural carbohydrates in maize and sorghum were accumulated mainly as Mono- and Disaccharose. The concentrations of Mono- and Disaccharose were increased markedly after differentiation of growing points and shown at early milk stage the highest contents with 27.8-29.1% and 16.8-20.4% for maizeand sorghums respectively. 2. Non-structural carbohydrates were accumulated mainly in stalk. However, during the late maturity the most of Mono- and Disaccharose were translocated into grain and reserved as starch. The increase of starch was associated with decrease of total non-structural carbohydrates. 3. Fructosan synthesis was not affected by morphological changes and environmental factors, which shows a value of 1.5-2.5% in whole stage of maize and sorghum. 4. Sorghum and maize plants were shown to have a great photosynthetic rates to high temperature. Reserved Mono- and Diaaccharose were, however, declined when temperature exceeded 30 dog C. Under cold stress at l8/8 deg C non-structural carbohydrates were not translocated and also were accumulated in leaves too much that cause to restrict of photosynthesis. 5. Net Energy Lactation (NEL) of sorghum and maize were directly associated with synthetic rates of non-structural carbohydrates, especially Mono- and Disaccharose. The highest values of NEL were found at physiological maturity stage with 6.6- 6.9 MJ and 5.7-6.0 MJ-NEL/kg for maize and sorghum respectively.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.6 no.2
• /
• pp.111-118
• /
• 1986

Sysnthesis and accumulation pattern or nonstructural carbohydrates in orchardgrass (Dactylis glomerata L.) cv. Potomac and Baraula, perennial ryegrass (Lolium perenne L.) cv. Reveille and Semperweide and meadow fescue (Festuca pratensis Huds.) cv. Cosmos 11 and N.F.G. were studied under different meteorological environments and cutting managements. The field experiments were conducted as a split plot design with three cutting regimes of 6-7 cuts at grzing stage, 4-5 cuts at silage stage and 3 cuts at hay stage in Korea and West Germany from 1975 to 1979. The results obtained are summarized as follows: 1. Accumlation of nonstructural carbohydrates in temperate grasses was influenced by grass species and regional climatic environments. Total nonstructural carbohydrates (TNC) of orchardgrass, perennial ryegrass and meadow fescue in Korea, taken as average of all cutting regimes, were shown a value of 4.39%, 6.08% and 8.01%, respectively, while those under cool summer climatic condition in West Germany accumulated to 10.42% (orchardgrass), 18.02% (perennial ryegrass) and 12.73% (meadow fescue). 2. Nonstructural carbohydrates in orchardgrass were accumulated mainly as mono-and disaccharose, while those in perennial ryegrass resreved as fructosan. The contents of fructosan and mono-and disaccharose were 1.34% and 3.04% for orchardgrass, 3.25% and 2.83% for perenninal ryegrass, respectively. Meadow fescue had a concentration of 3.93% fructosan and 4.08% mono-and disaccharose. 3. Synthesis and accumulation of nonstructural carbohydrates in temperate grasses were negative associated with increasing of air temperature (P$\leq$ 0.1%). Under hot stress during summer season in Korea, the contents of fructosan, mono-and disaccharose were decreased to about 0.34% nd 1.28% from a value of 1.34% and 2.69% in spring season. In Freising and Braunschweig, the concentration of reserved carbohydrates was less influenced by growing season. 4. Synthesis and accumulation pattern of nonstructural carbohydrates were shown a great respons to cutting frequency of the plants. Frequent cutting system under high temperature lowered the accumulation of reserved carbohydrates, especially fructosan and also caused to decrease the plant regrowth. However, under cool temperature, it shows a less differences of tructosan, mono-and disaccharose in the plants at all cutting systems.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.3
• /
• pp.156-164
• /
• 2004

This study was conducted to evaluate the effect of the application of green manure in the form of either green barley and Chinese milkvetch in reducing the amounts of N fertilizers and conventional fertilizers needed for paddy rice. Prior to rice transplanting, the green barley and Chinese milkvetch as a green manure produced respectively $668kg\;10a^{-1}$ and 3,492kg\;$10a^{-1}$ in fresh shoot weight basis. Calculated nitrogen content from harvested green manures was 3.9 and $17.8kg\;10a^{-1}$, respectively. Plant height and tiller number of rice increased when two kinds of green manure incorporated into soil. Above mentioned parameters also increased with increasing amounts of N fertilizers at both ear formation and heading stage of rice. Rice grain number was not affected by green manures treatment but increased when N fertilizers were applied. Although rice panicle and grain number increased with green manure treatments and fertilizer applications, whereas the percentage of ripened grain decreased. Chinese milkvetch with additional N fertilizer applications increased brown rice yield from 1 to 5% compared to rice yields in plots where non-green manure with the conventional amount of fertilizer application was applied. Rice treated with Chinese milkvetch and 30% of the conventional N fertilizer rate yielded the same as rice fertilized conventionally. During the rice growing season, $NH_4-N$ content of paddy soil was higher in green manures treatment than non-green manure one. Average $NH_4-N$ content in paddy soil drastically decreased after heading stage below $5.7mg\;kg^{-1}$ in non-green manure treated plots. While on the other, $NH_4-N$ content in soil slowly decreased in plots those were treated with green manures at harvesting stage, average $NH_4-N$ content was still greater than $5.5mg\;kg^{-1}$. Nitrogen content of rice shoot and brown rice seed was higher in green manure treatment.

• Journal of Bio-Environment Control
• /
• v.3 no.2
• /
• pp.119-127
• /
• 1994

This study was conducted to investigate the effects of temperature and light conditions on the vigor and growth responses of red pepper(Capsicum annuum L.) seedlings in the nonheated plastic houses with triple and quadruple coverings during winter. The results obtained were as follows ; 1. The growth in terms of plant height, number of leaves, leaf area and dry weight of each organ was reduced up to 50% in the triple coverings compared to quadruple ones. The greatest difference between the triple coverings and quadruple ones was the leaf area, showing two to five times larger in the quadruple ones. Therefore, the differences of the early environmental conditions during raising seedling stage was well reflected. 2. The leaf expansion in the early stage of seedling was delayed in the triple coverings and subsequently crop growth rate(CGR) significantly reduced. The specific leaf area (SLA) in the triple coverings was less than quadruple ones. The net assimilation rate (NAR) was increased in the early stage of seedlings and then reduced in the quadruple coverings. In triple ones, however, the great reduction showed at six weeks after sowing and then increased sharply. 3. The linear relationship among leaf area, total dry weight and leaf dry weight was observed in the all experimental areas, while between leaf area and crop growth rate only in the quadruple coverings, and between leaf area and net assimilation rate in both triple and quadruple ones. 4. The dry matter partitioned to the leaf increased up to six weeks after sowing in the triple coverings but reduced in the stem and root. However, the adverse results were obtained in the quadruple ones. 5. In the triple coverings, the number of branches showed the exponential increment while fruit weight showed linear increment in both triple and quadruple ones. Higher yield was obtained in the quadruple ones. 6. The shoot dry weight among the characteristics of seedlings was greatly contributed to the yield of red pepper after transplanting. Accordingly, one of the decisive criterion for good quality of red pepper seedlings was determined by the highest correlation between shoot dry weight of growing plant and fruit yield of pepper plant.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.10 no.1
• /
• pp.1388-1393
• /
• 1968

Higher yield in rice paddies is greatly dependent on adequately balanced and timely supply of water. A majority of rice paddy in Korea is generally irrigated by rainfall, but in many cases it has to be supplemented by artificial irrigation for optimum rice culture. Although the water requirement of rice plant is far higher than that of other crops, submerged condition of rice paddy is not necessarily required. The moisture requirement of rice plant varies with its growing stages, and it is possible to increase the irrigation efficiency through reduction of water loss due to percolation in rice paddies. An experiment was conducted on the effectiveness of economical use of water by different irrigation period and different method of cultivation. The experimental plots were set up by means of randomized block design with three duplications; (a) Alltime submerged (b) Economically controlled, and (c) Extremely controlled. Three different irrigation periods were (a) Initial stage (b) Inter-stage, and (c) last stage. The topsoil of the three plots were excavated to the depth of 30cm and then compacted with clay of 6 cm thickness. Thereafter, they were piled up with the excavated top soils, leveled and cored with clay of 6cm thickeness arround footpath in order to prevent leakage. The results obtained frome the experiments are as follows; (1) There is no difference among the three experiment plots in terms of physical and chemical contditions, soil properties, and other characteristics. (2) Colulm length and ear length are not affected by different irrigation methdos. (3) There is no difference in the mature rate and grain weight of rice for the three plots. (4) The control plot which was irrigated every three days shows an increased yield over the all the time submerged plot by 17 persent. (5) The clay lined plot whose water holding capacity was held days long, needs only to be irrigated every 7 days. (6) The clay lined plot showes an increased yield over the untreated plot; over all the time submerged plot by 18 percent, extremely controlled plot by 18 percent, and economically controled plot by 33 percent.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.3
• /
• pp.181-194
• /
• 2002

Parasitism is a one-sided relationship between two organisms in which one benefits at the expense of the other. Parasitic dinoflagellates, particularly species of Amoebophrya, have long been thought to be a potential biological agent for controlling harmful algal bloom(HAB). Amoebophrya infections have been reported for over 40 species representing more than 24 dinoflagellate genera including a few toxic species. Parasitic dinoflagellates Amoebophrya spp. have a relatively simple life cycle consisting of an infective dispersal stage (dinospore), an intracellular growth stage(trophont), and an extracellular reproductive stage(vermiform). Biology of dinospores such as infectivity, survival, and ability to successfully infect host cells differs among dinoflagellate host-parasite systems. There are growing reports that Amoebophrya spp.(previously, collectively known as Amoebophrya ceratii) exhibit the strong host specificity and would be a species complex composed of several host-specific taxa, based on the marked differences in host-parasite biology, cross infection, and molecular genetic data. Dinoflagellates become reproductively incompetent and are eventually killed by the parasite once infected. During the infection cycle of the parasite, the infected host exhibits ecophysiologically different patterns from those of uninfected host in various ways. Photosynthetic performance in autotrophic dinoflagellates can be significantly altered following infection by parasitic dinoflagellate Amoebophrya, with the magnitude of the effects over the infection cycle of the parasite depending on the site of infection. Parasitism by the parasitic dinoflagellate Amoebophrya could have significant impacts on host behavior such as diel vertical migration. Parasitic dinoflagellates may not only stimulate rapid cycling of dissolved organic materials and/or trace metals but also would repackage the relatively large sized host biomass into a number of smaller dinospores, thereby leading to better retention of host's material and energy within the microbial loop. To better understand the roles of parasites in plankton ecology and harmful algal dynamics, further research on a variety of dinoflagellate host-parasite systems is needed.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.2
• /
• pp.217-228
• /
• 2003

Co-ordinate growth of the brain and skull is achieved through a series of tissue interactions between the developing brain, the growing bones of the skull and the sutures that unite the bones. Craniosynostosis, the premature fusion of cranial sutures, presumably involves disturbance of these interactions. Bmp2, one of bone morphogenetic proteins (Bmps), is involved in the regulation of the shapes of individual bones and the relative proportions of the skeleton. Mutations in the homeobox gene Msx2, known as a downstream gene of Bmp, cause Boston-type human craniosynostosis. The phenotype of Dlx5 homozygote mutant mouse presents craniofacial abnormalities including a delayed ossification of calvarial bone. These facts suggest important roles of Bmp2, Msx2 and Dlx5 genes in the cranial bone growth and suture morphogenesis. To elucidate the function of these molecules in the early morphogenesis of mouse cranial sutures, we first analyzed by in situ hybridization the expression of Bmp2(E15-18), Msx2 and Dlx5 genes in the developing sagittal suture of calvaria during the embryonic stage. Bmp2 mRNA was intensely expressed in the osteogenic fronts and also at the low level in the periosteum of parietal bones during embryonic stage, Msx2 mRNA was intensely expressed in the sutural mesenchyme and mildly expressed in the dura mater during the embryonic stage. Dlx5 mRNA was intensely expressed osteogenic fronts and parietal bones. To further examine the role of Bmp signaling in cranial suture, we did in vitro experiments in E15.5 mouse calvarial explants. Interestingly, implantation of Bmp2-soaked beads onto the osteogenic fronts after 48 hours organ culture resulted in the increase of the tissue thickness and cell number around Bmp2 beads, compared to BSA control beads. In addition Bmp2 induced etopic expressions of Msx2 and Dlx5 genes. On the other hand, overexpression of FGF2 did not induce the expression of Msx2 and Dlx5. Taken together, these data indicate that Bmp2 signaling molecule has a important role in regulating the cranial bone growth and early morphogenesis of cranial suture. We also suggest that Bmp signaling is involved in all the stages of osteogenesis of cranial bones and the maintenance of cranial suture by regulating Msx2 and Dlx5 genes, and that Msx2 and Dlx5 genes are specific transcription factors of Bmp signaling pathway.

• Korean Journal of Soil Science and Fertilizer
• /
• v.18 no.3
• /
• pp.247-253
• /
• 1985

In order to investigate the effects of water temperature on chemical properties of soil and nutrient uptake of rice plant, four varieties of rice were cultivated in a field where water temperature range was $17.3-23.0^{\circ}C$ and plant samples were taken at three growing stages and were analyzed in detail. The results were summarized as follows: 1. Organic matter content and pH of surface soil were showed no differences while the contents of $P_2O_5$ and $SiO_2$ were increased and potassium was decreased as the water temperature increased. 2. The amounts of nutrient uptake were related to the water temperature and the total nutrient contents of rice plants at harvesting stage were in order of $SiO_2$ > $K_2O$ > T-N > $P_2O_5$ > MgO. The rate of $SiO_2$/N and $K_2O$/N of rice plants grown at water temperature $23.0^{\circ}C$ were over two times to those of the water temperature $17.3^{\circ}C$. 3. Nutrient contents of rice plants showed a increasing tendency as increasing the water temperature. However, nutrient contents such as T-N at whole period, $P_2O_5$ at heading and harvesting stage, and $K_2O$ at heading stage were higher at low water temperature than those of high water temperature. 4. Most of nitrogen was translocated and accumulated in grain, potassium in straw respectively. All nutrients translocated to grain more easily as the water temperature increased.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.4
• /
• pp.510-517
• /
• 2015

Miscanthus has been considered as the most promising bioenergy crop for lignocellulosic biomass production. In Korea, M. sacchariflorus and M. sinensis can be found easily in all regions. It is a great advantage to utilize as important species with respect to genetic and cross-breeding programs materials for creation of novel hybrids. For successful breeding programs, it is important to precisely understand the variability of flowering traits among Miscanthus species as breeding parents materials. In this study, flowering traits were observed daily in 960 germplasms of two Miscanthus species (M. sacchariflorus and M. sinensis) for growing seasons over 2 years. The flowering process was divided into three stages. ST (sprouting time) was recorded when first leaf of the plant emerged on soil. FS1 (flowering stage 1) and FS2 (flowering stage 2) were recorded when flag leaf was firstly observed, and 1 cm of panicle was showing on at least one stem, respectively. For 2013 and 2014, the latest germplasms exerted flag leaf, i.e. September 30 (DOY of FS1 164.1) and September 4 (DOY of FS1 141.0) occurred M. sacchariflorus cv. Geodae 1 and M. sacchariflorus cv. Uram collected from Southern Korea (Jeollanam-do), while Miscanthus germplasms collected from northern Korea (Gyeonggi-do) which emerged the earliest flag leaf in July and August, significantly decreased DOY. For DOY from ST to FS2, M. sacchriflorus germplasms ranged from 140 to 190 days, and 110 to 170 days for 2013 and 2014. The highest frequency showed to 160 days for 2013, and 150 days for 2014. In M. sinensis germplasms, the highest frequency showed to 180 days for 2013, and 170 days for 2014. In the results of correlation between the day of years from ST to FS2 for 2013 and 2014, M. sacchriflorus and M. sinensis showed high coefficient of correlation (0.70 and 0.89). It can be supposed that flowering characteristics of Miscanthus are largely affected by the unique phenotypic characteristic of native habitat than environmental factors of the current planted site. This study for flowering traits of Miscanthus may provides an important information in order to expedite the introduction as breeding materials for creation of new hybrid.