• Korean Journal of Medicinal Crop Science
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• v.14 no.4
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• pp.217-220
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• 2006

It is known that the process of variety development and maintenance of original plant is difficult in Angelica gigas and Angelica acutiloba because they are allogamous plants. The contents like this are stand in the way of theirs breeding. This study was conducted to investigate the foraging activity and pollinational efficacy by insects to flowers of A. gigas and A. acutiloba. Foraging activity by pollinators was observed every day from 10:00 to 10:30 during 3 days after September 21. Honey bee and fly were major pollinators. The rate of hymenoptera and diptera to total numbers of insects was the 56.5% and 40.6% in A. gigas, respectively. It was also 46.3% and 51.8% in A. acutiloba, respectively. The other insects were lepidoptera, coleoptera and hemiptera. The numbers of hymenoptera and diptera were more in flowers of A. gigas was 49.2% with bee, 36.0% with fly, 15.3% with human, 0.9% without anything in the nethouse and 76.6% in the open field. That of A. acutiloba was 43.6% with bee, 27.9% with fly, 20.3% with human, 0.6% without anything in the nethouse and 46.9% in the open field. Excepting open field, seed setting rate of with bee in the nethouse was the highest of all the others. However, we concluded that the use of fly was the most effective method for pollination of A. gigas and A. acutiloba considering low cost and convenient handling.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.380-387
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• 2013

The objective of this study is to investigate the effect of elevated $CO_2$ and temperature on the phenology and reproductive ecological characteristics of Bupleurum latissimum. We measured characteristics of 4-year-old B. latissimum grown under control (ambient $CO_2$+ambient temperature, 340~370 ppm) and treatment (elevated $CO_2$+elevated temperature, 690~770 ppm) conditions in a glass house. The period of flowering, fruit appearance and fruit maturing was earlier by 4, 1, 2 days, respectively, under elevated $CO_2$ and temperature. The comparative weight of a single ripe fruit, all ripe fruits and total ripe and unripe fruits was higher per control than treated plants. However the other characteristics, such as no. of peduncle, matured fruits, total fruits per plant and fruit setting rate per plant of B. latissimum were not significantly affected by elevated $CO_2$ and temperature. The germination rate of B. latissimum was higher in control than in treatment plants. These results showed that the phenology of B. latissimuin might be well suited to an earlier growing season, and the response of reproductive characteristics of B. latissimuin is negatively influenced by global warming.

• Journal of Plant Biology
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• v.3 no.2
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• pp.6-18
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• 1960

The present experiments were designed in order to clarify the differences between the long and short styled plants and the transgressive gradition in the degree of dimorphism among the three heterostylous species of the Polygonus, P. japonica, F. esculentum, and P. senticosa, based on investigations regarding the floral structure, ecological and physiological traits, the results of which are summarized as follows: (1) P. japonica, although it exhibits typical dimorphism, has undergone so high a differentiation between long and short styled that its long styled individuals behave as if they were female; and short styled individuals as if male. In long-styled individuals, filament, anther, and pollen grains show signs of degeneration, most of the pollen being abortive. On the other hand, in short styled individuals, the filament, anther, and pollen grains have attained remarkable development; the pollen grians are large and fertile. In short-plant the fertilized flowers readily drop off in every stage of their embryo development. This species has completely lost the self-fertile property, which is characteristic of the non-dimorphic Polygonum genus. Although this specsei typically exhibits the physiological characteristics of the non-dimorphic Polygonum genus. Although this specisei typically exhibits the physiological characteristics of dimorphism in controlled pollination, the short-styled individuals bear no seed in nature, thus misleading taxonomists to idenfity the short-styled plant as male. 2) The morphological feature of the flower organ of P. senticosa obviously indicates definite dimorphism. Physiologically, however, no differentiation towards dimorphism was observed, the species still retaining, both in long and short-individuals, the self-fertile property common to the Polygonum genus. Elaborate examinations revealed that regardless of the modes of pollination, both fertiization and seed setting flourish, no differentiation betwen legitimate and illegitimate unions being recognizable. This sort of physiological property has not been observed in the investigations of other heterostylous plants. It is assumed that this species is differentiated structurally into dimorphism, but not yet physiologically. In nature, however, this plant would have more opportunities to be cross-pollinated, i.e., legitimately combined, than self-pollinated because of the development of two forms of flowers. 3) In terms of heterostylism, the F. esculentum just occupies the intermediate position between P. japonica and P. senticosa structurally, ecologically, and physiologically. Doescription of some of the physiological behavior of the plant will suffice to demonstrate the above facts. While P. japonica has completely lost its self-fertile property, P. senticosa still retains it wolly. In F. esculentum 2-6% of self-fertility is the result in illegitimate combination. There occur occasionally hereditary self fertile individuals among some of the F. or 20 min. irradiation plot, when they reach any stage of the same bacterial population. In addition to this increase of total population in the plots with the more dose of UV light irradiation, it seems that the more dose of UV light irradiation is the more shortened the generation time of Azotobacter. Therefore, it is clear that variation of reproductive rate must be, mere or less, due to the genetic effects induced by UV light irradiation. On the other hand, the lag phase or logarithmic growth phase in nonirradiated culture is shortened prominently, and this must be due to the difference in bacterial number of the original inoculm. The generation time of Azotobacter is shortened by exogeneous treatment of nuclei acid derivatives, and the degree is greater in case of DNA derivatives than RNA dervatives. W.H. Price reported that the rate of ribose nucleic acid to protein in Staphylococcus muscae is proportional to the generation time: that is the faster the cell can form ribose nucleic acid, the more rapid its growth. This explains the shortening of generation time by exogeneous RNA derivatives in this work reasonably. On the other hand, it is well known that the desoxyribose nuclic acid content per cell is constant and independent of the generation time. A.D. Laren and W.N. Takahashi reported that the infectious RNA from TMV is 6 times as sensitive to inactivation by UV as it is in the form of intact virus, and that inactivation of infectious TMV involves onlu a local change on RNA chain. But, the effect of exogeneous DNA in this work suggests that irradiated living cell which cotain DNA bring about some change on DNA moleculs as well as RNA molecules. And if the mutagenic effects of UV take into consideration, it is very reasonable. Therefore, it is clear that the variation of the generation time by UV irradiation is, more or less, due to the genetic effects. Therefore, it seems that the shortness of the average lifewpan of Azotobacter by UV irradiation is resulted not only from the influence of the environmental conditions, but also from the variation of genetic factor of the individual.

• Molecules and Cells
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• v.24 no.1
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• pp.83-94
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• 2007

During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with $F_2$ and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.658-675
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• 2016

The environmental characteristics of the habitats, the population structures, ecological niche, life traits and the population demography are used as an essential informations to the effective conservation plans about the target species. We first confirmed a total of 37 populations through 12 years of investigation on the extents, and investigated the environmental factors of habitats and the population structures of the 25 cohorts in 12 regions among them. And, we investigated the population dynamics targeting at 8 cohorts in the population of Daegwanryeong-myeon, Pyeongchang-gun, Gangwon-do. Along with this, we conducted 4 years of cultivation experiments and how pollinators affect the success of reproduction. The results shows that the Paeonia obovata Maxim. was found in a relatively wide range of habitats. For the population structures of the 25 cohorts, there were considerable differences among cohorts, including a case which showed relative stable structure and an extreme case in which only adults were found. The factor that affected the population dynamics during the investigation was thought as a forest gap created in the tree layer. In the cultivation experiment, seedlings grew well in a less soil organic matter. The seed setting rate and the number of seeds generated by visiting pollinators were higher trends. In conclusion, to understand the distribution of the Paeonia obovata Maxim., there needs to be investigated on the other factors that are involved in dispersal factors other than environmental factors, and thus we suggest the necessity of the research on the dispersal vectors. The current Paeonia obovata Maxim. population was thought as a process of expansion after the rapid reduction of the extents in the past. For the effective conservation of the Paeonia obovata Maxim., an endangered plant, we recommend to understand the species through the spatio-temporal expansion, and maintain the health of the ecosystem based on it.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.445-460
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• 2017

This study was carried out for three years from 2013 to 2015 to investigate the actual condition of pest control of domestic persimmon organically cultivated farmers, to select environment - friendly pest control materials for major pests, and to conduct field test of established control system. The main cultivated cultivar of the reader farmer of organic cultivation was "Buyou" and sprayed organic agricultural material 9~17 times per year for pest control. The most harmful pests were anthracnose, bugs, persimmon fruit worm, and scales, etc. The control materials used were organic lime sulfur mixture, red clay sulfur, emulsifier, bordeaux solution, and self-made plant extracts using garlic, ginkgo nut and pine tree. The effective materials for controlling anthrax were lime sulfur mixture and red clay sulfur. Garlic oil + citronella emulsion, shrubby sophora seed extract + tea extract was effective to control Riptortus clavatus and Euproctis subflava. When installed 60 ea per 10a of mating disruption trap in a sweet orchard, the fruit setting rate was improved by 30%. The results of field test of control system to control 10 times a year in organically grown persimmons were able to harvest fruit of 70.7%. However, since any kinds of pesticides can not be sprayed during the harvest season in September and October, the damaged by bugs did not decreased, and further research is needed.

• Applied Biological Chemistry
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• v.11
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• pp.173-184
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• 1969

To elucidate the effect of Amo-1618(4-hydroxyl-5-isopropyl-2-methlphenyl trimethyl ammonium chloride, 1-piperidine carboxylate) known as a kind of growth retardant, on the growth, grain yield, increasing the efficiency of nitrogen fertilizer, behavior of mineral nutritions and the rate of phosphorus utilization, this experiment was conducted pot culture method in a vinyl house. Two nitrogen level, namely, practical nitrogen level(1 N) and three times nitrogen level(3 N) was made and labelled double-calcium-superphosphate $Ca(H_2P^{32}O_4)_2.\;2H_2O)$ as a source of radioactive phosphorus(P-32) was employed $80\;{\mu}c/pot$, respectively. Rice seedlings, variety 'Suwon No. 82', was transplanted to a 1/50,000 a china pot on June 13 in 1968. For treatment, at early stage of tillering, 10,000 ppm solution of Amo-1618 was foliar sprayed only one time. The Duncan's new mutiple-range test was adopted for statistical analysis evaluating experimental data at 5% level significance. The results obtained may be summarized as follows; 1) No significant difference was found among the treatments in plant height, but in plot of Amo-1618 treatment and 3 N level, number of tillers was significantly increased than that of others. 2) Weight of 10,000 kernels and seed-setting rate was also remarkably increased in same treatment above. 3) Grain yield per pot was significantly increased in Amo-1618 and 3 N level application. This results seemed to be due to the increased the factors on the yield. 4) Contents of nitrogen and phosphorus per cent in the grain was likewise increased in Amo-1618 and 3 N application. There is, however, no difference among treatments in the content of nitrogen and phosphorus in the leaves and culms of rice plants. 5) On the other hand, the contents of potassium and magnesium, no distinctly tendeny showed among treatments. 6) The rate of phosphorus utilization was significantly increased in the plot of Amo-1618 and 3 N application.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.219-225
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• 2004

This study was conducted to evaluate growth and yield characteristics and the contribution to the yield according to the emergent sequence of tiller under two planting density $(60{\times}15\;cm,\;60{\times}25\;cm)$ in Coix lachryma-jobi L. var. mayuen Stapf. The average culm length and number of rachillas of $60{\times}25\;cm$ planting density were 20 cm shorter and 4.7 higher, respectively, whereas seed setting position of $60{\times}25\;cm$ planting density was 1.7 nodes lower compared with $60{\times}15\;cm$ planting density. Culm length and culm diameter of each tiller became shorter and thinner as the tiller emerged later. Length of rachillas was longer, number of grains was higher and ripening rate was also higher in $60{\times}25\;cm$ planting density than those of $60{\times}15\;cm$ planting density, whereas 100 grain weight in $60{\times}25\;cm$ planting density was lower by 0.5 g compared with $60{\times}15\;cm$ planting density. Length of rachillas and number of grains according to the emergent sequence of tiller were shown shorter and lower as the tiller emerged later. The highest number of bract was obtained from the main culm in both planting densities. 100 grain weight according to the emergent sequence of tiller became lower as the tiller emerged later in $60{\times}15\;cm$ planting density, but there was no clear tendency in $60{\times}25\;cm$ planting density. Among 8 tillers, 5th tiller and 4th tiller of main culm contributed 84.4% to the yield in $60{\times}15\;cm$ planting density, while it was 84.1% in $60{\times}25\;cm$ planting density. Analysis of path coefficient to grain yield showed that direct effect was the highest in the number of grain per tiller followed by in the 100 grain weight and in ripening rate.

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

• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.31-68
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• 1990

The concentration of economic power takes the form of one or a few firms controlling a substantial portion of the economic resources and means in a certain economic area. At the same time, to the extent that these firms are owned by a few individuals, resource allocation can be manipulated by them rather than by the impersonal market mechanism. This will impair allocative efficiency, run counter to a decentralized market system and hamper the equitable distribution of wealth. Viewed from the historical evolution of Western capitalism in general, the concentration of economic power is a paradox in that it is a product of the free market system itself. The economic principle of natural discrimination works so that a few big firms preempt scarce resources and market opportunities. Prominent historical examples include trusts in America, Konzern in Germany and Zaibatsu in Japan in the early twentieth century. In other words, the concentration of economic power is the outcome as well as the antithesis of free competition. As long as judgment of the economic system at large depends upon the value systems of individuals, therefore, the issue of how to evaluate the concentration of economic power will inevitably be tinged with ideology. We have witnessed several different approaches to this problem such as communism, fascism and revised capitalism, and the last one seems to be the only surviving alternative. The concentration of economic power in Korea can be summarily represented by the "jaebol," namely, the conglomerate business group, the majority of whose member firms are monopolistic or oligopolistic in their respective markets and are owned by particular individuals. The jaebol has many dimensions in its size, but to sketch its magnitude, the share of the jaebol in the manufacturing sector reached 37.3% in shipment and 17.6% in employment as of 1989. The concentration of economic power can be ascribed to a number of causes. In the early stages of economic development, when the market system is immature, entrepreneurship must fill the gap inherent in the market in addition to performing its customary managerial function. Entrepreneurship of this sort is a scarce resource and becomes even more valuable as the target rate of economic growth gets higher. Entrepreneurship can neither be readily obtained in the market nor exhausted despite repeated use. Because of these peculiarities, economic power is bound to be concentrated in the hands of a few entrepreneurs and their business groups. It goes without saying, however, that the issue of whether the full exercise of money-making entrepreneurship is compatible with social mores is a different matter entirely. The rapidity of the concentration of economic power can also be traced to the diversification of business groups. The transplantation of advanced technology oriented toward mass production tends to saturate the small domestic market quite early and allows a firm to expand into new markets by making use of excess capacity and of monopoly profits. One of the reasons why the jaebol issue has become so acute in Korea lies in the nature of the government-business relationship. The Korean government has set economic development as its foremost national goal and, since then, has intervened profoundly in the private sector. Since most strategic industries promoted by the government required a huge capacity in technology, capital and manpower, big firms were favored over smaller firms, and the benefits of industrial policy naturally accrued to large business groups. The concentration of economic power which occured along the way was, therefore, not necessarily a product of the market system. At the same time, the concentration of ownership in business groups has been left largely intact as they have customarily met capital requirements by means of debt. The real advantage enjoyed by large business groups lies in synergy due to multiplant and multiproduct production. Even these effects, however, cannot always be considered socially optimal, as they offer disadvantages to other independent firms-for example, by foreclosing their markets. Moreover their fictitious or artificial advantages only aggravate the popular perception that most business groups have accumulated their wealth at the expense of the general public and under the behest of the government. Since Korea stands now at the threshold of establishing a full-fledged market economy along with political democracy, the phenomenon called the concentration of economic power must be correctly understood and the roles of business groups must be accordingly redefined. In doing so, we would do better to take a closer look at Japan which has experienced a demise of family-controlled Zaibatsu and a success with business groups(Kigyoshudan) whose ownership is dispersed among many firms and ultimately among the general public. The Japanese case cannot be an ideal model, but at least it gives us a good point of departure in that the issue of ownership is at the heart of the matter. In setting the basic direction of public policy aimed at controlling the concentration of economic power, one must harmonize efficiency and equity. Firm size in itself is not a problem, if it is dictated by efficiency considerations and if the firm behaves competitively in the market. As long as entrepreneurship is required for continuous economic growth and there is a discrepancy in entrepreneurial capacity among individuals, a concentration of economic power is bound to take place to some degree. Hence, the most effective way of reducing the inefficiency of business groups may be to impose competitive pressure on their activities. Concurrently, unless the concentration of ownership in business groups is scaled down, the seed of social discontent will still remain. Nevertheless, the dispersion of ownership requires a number of preconditions and, consequently, we must make consistent, long-term efforts on many fronts. We can suggest a long list of policy measures specifically designed to control the concentration of economic power. Whatever the policy may be, however, its intended effects will not be fully realized unless business groups abide by the moral code expected of socially responsible entrepreneurs. This is especially true, since the root of the problem of the excessive concentration of economic power lies outside the issue of efficiency, in problems concerning distribution, equity, and social justice.