• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.151-158
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• 1993

Since the inhibition of floral induction was considered to be an important subject to get high yield of Angelica gigas, the effects of low temperature, daylengh and shading were investigated in this study. The yield of A. gigas root grown by inhibition of floral induction was compared with the yield obtained by traditional cultivation method. When the seedings were exposed to the natural low air temperature condition until late of November, the plants which had 6 to 8 leaves showed vernalizing effect, and when the low temperature treatment was prolonged until mid of January, 4 to 5 leaf plants showed vernalizing effect. But 2 to 3 leaf plants did not show vernalizing effect regardless of the length of chilling treatment. The effectiveness of exposure to low temperature was markedly dependent upon the age of plants. In the artificial low temperature treatment the range of temperature varied with plant age. Vernalizing effect at 1,5 and 9$^{\circ}C$ of temperature did not show 3,5,6 leaf plants, respectively. The bolting percent in 8 leaf plant at 1,5 and 9$^{\circ}C$ for 8 weeks decreased by 80,45 and 5%, respectively. As daylength became longer, the bolting percent of A. gigas was increased. plants which were grown in the full sunlight showed the highest value in bolting percent, and the bolting percent was not decreased significantly with changing from full sunlight to 50% shading. When A. gigas were grown by the inhibition of floral induction, dry root weight per l0a showed the greatest value in 3 year old plant which 3.6 and 2.4 times higher than that of 1 and 2 year old plant, respectively. The yield of root was increased by 73.7% in 2 year old plant and 159.6% in 3 year old plant compared with the yield obtained by traditional cultivation method.

• Journal of Aquaculture
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• v.14 no.3
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• pp.173-180
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• 2001

Regulation of copulation and parturition of black rockfish, Sebastes schlegeli were induced by artificially controlled photoperiod and temperature. for the treated group, daylength of copulation and parturition period was maintained at 9L : 15D and 14L : l0D, respectively. Temperature was maintained at 12~13$^{\circ}C$ during the copulation period, and at 14~15$^{\circ}C$ during the parturition period. Gonadosomatic index (GSI) of male was low 0.12 from January to August and peak to 1.36~0.10 during November in the control group but 1.27 ~ 0.05 during October in treated group. GSI of female was about 1.82 from January to November 1996 and reached the maximum of 46.5 ~ 5.72 during April 1997 in the control group but 42.0~4.24 during february 1997 in the treated group. The pattern of ovary and testis development did not much differ between the treated and control groups. However, the copulation and parturition of black rockfish could be advance 2~3 months by controlling photoperiod and temperature.

• Ocean and Polar Research
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• v.38 no.1
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• pp.47-57
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• 2016

Effects of environmental factors on the zoospore release and germling growth of Chaetomorpha linum were examined. Zoospore release and germling growth experiments were carried out under a combination of temperatures ${\times}$ irradiances, and a single factor of irradiances, salinities, daylength and nutrients (nitrogen, phosphorus). Zoospore release was maximal under condition of $20^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in a factorial experiment (temperatures ${\times}$ irradiances), at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ in irradiance experiment and at 34 psu in salinity conditions. After 24 days in culture, germling growth was maximal at $25^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in temperatures ${\times}$ irradiances and at normal seawater (34 psu) in salinity. Germling growth is faster at higher irradiance under same temperature condition and it increased with increasing daylengths (8-16 h). Chaetomorpha linum grew in wide range of N and P concentrations. The growth of germling was maximal at $50{\mu}M\;{PO_4}^{3-}$ and $40{\mu}M\;{NH_4}^+$. Germling growth was more effective under nitrogen addition than phosphorus addition in culture. In conclusion, optimal environmental conditions for zoospore release were $20^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, and 34 psu. In addition, the optimal germling growth was observed at $25^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, 34 psu, 16 h, $50{\mu}M\;({PO_4}^{3-})$ and $40{\mu}M\;{(NH_4}^+)$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.253-263
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• 2016

Chrysanthemum production would benefit from crop growth simulations, which would support decision-making in crop management. Chrysanthemum is a typical short day plant of which floral initiation and development is sensitive to photoperiod. We developed a model to predict phenological development and leaf appearance of chrysanthemum (cv. Baekseon) using daylength (including civil twilight period), air temperature, and management options like light interruption and ethylene treatment as predictor variables. Chrysanthemum development stage (DVS) was divided into juvenile (DVS=1.0), juvenile to budding (DVS=1.33), and budding to flowering (DVS=2.0) phases for which different strategies and variables were used to predict the development toward the end of each phenophase. The juvenile phase was assumed to be completed at a certain leaf number which was estimated as 15.5 and increased by ethylene application to the mother plant before cutting and the transplanted plant after cutting. After juvenile phase, development rate (DVR) before budding and flowering were calculated from temperature and day length response functions, and budding and flowering were completed when the integrated DVR reached 1.33 and 2.0, respectively. In addition the model assumed that leaf appearance terminates just before budding. This model predicted budding date, flowering date, and leaf appearance with acceptable accuracy and precision not only for the calibration data set but also for the validation data set which are independent of the calibration data set.

• FLOWER RESEARCH JOURNAL
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• v.17 no.2
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• pp.106-113
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• 2009

Germination percentage of Korean native lily seeds was high at $20-25^{\circ}C$. It was almost 100% in L. cernuum, L. callosum, L. amabile, and L. concolor, 88.0% in L. lancifolium, and 73.0% in L. maximowitzii, respectively. Meanwhile, it was low rate of 34.0%-54.0% in L. distichum, L. hansonii, and L. tsingtauense. Germination was mostly delayed of $15^{\circ}C$ and days to germination were more shortened in species with higher germination percentage. Even though the effect of daylength was not considerable in germination rate, it was promoted in L. maximowitzii but it was delyed in L. hansonii under long day. The effect of soaking in hot PGRs solution in L. callosum, L. cernuum, L. amabile, L. lancifolium, and L. concolor did not show any difference in comparison with non-treatment. However, it was improved by BA in L. maximowitzii. Longer period of cold wet storage resulted in improved germination percentage in L. maximowitzii and L. lancifolium, while it affected decreased percentage in L. distichum and L. hansonii. Days to germination were shortened by longer period of cold wet storage regardless of species. Germination percentage in dry storage was higher under cold temperature than room temperature and under desiccator storage than outside desiccator, it was highest under desiccator storage at $4^{\circ}C$. It was drastically reduced by the non-use desiccator storage at room temperature L. concolor, however it was improved only by the use of desiccator L. maximowitzii for a long time.

• Ocean and Polar Research
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• v.40 no.4
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• pp.203-212
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• 2018

Zoospore release and germling growth of endophytic Ulvella ramosa were examined under various temperatures (10, 15, 20, $25^{\circ}C$) ${\times}$ irradiances (20, 60, $100{\mu}mol\;photons\;m^{-2}s^{-1}$). Additional growth experiments were performed at different salinities (15, 25, 35, 45 psu) and daylengths (8, 12, 16 h). Growth of host Gracilaria vermiculophylla (Ohmi) Papenfuss was estimated under combinations of temperatures (15, 20, 25, $30^{\circ}C$) and irradiances (20, 60, $100{\mu}mol\;photons\;m^{-2}s^{-1}$). Endophyte effects on the host growth were tested in the two temperatures (20, $30^{\circ}C$) and irradiances (60, $100{\mu}mol\;photons\;m^{-2}s^{-1}$). Zoospore release was maximal at $20^{\circ}C$ and $20{\mu}mol\;photons\;m^{-2}s^{-1}$, and germlings grew best under $20^{\circ}C$ and $60{\mu}mol\;photons\;m^{-2}s^{-1}$. No salinity effect on the growth of endophytes was found but endophyte growth was maximal under the daylength of 12 h. G. vermiculophylla grew better at higher irradiances but no growth differences were found between temperatures of $15-30^{\circ}C$. The growth of host species was significantly inhibited by endophytes under $20^{\circ}C$ and $60{\mu}mol\;photons\;m^{-2}s^{-1}$, but host G. vermiculophylla grew well in the endophyte inactive culture conditions of $30^{\circ}C$ and $100{\mu}mol\;photons\;m^{-2}s^{-1}$. In conclusion, endophyte effects on the production of host G. vermiculophylla could be minimized by controlling cultivation depth and harvest period to inhibit endophyte activity.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.891-899
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• 2015

The lily symptomless virus (LSV) is the most common virus in Korean native lilies and causes various types of damage to overall plant growth. This study was carried out to investigate the elimination rate of the LSV by the in vitro scale culture (scaling) method in Korean native lilies and to test reinfection rates of the LSV under several field culture conditions of bulb production. Four Korean native lilies (Lilium dauricum, L. distichum, L. lancifolium, and L. maximowitzii) were used and their scales were cultured in vitro for micro-scale formation. The micro-scales were subcultured repeatedly using MS culture medium supplemented with 30 or $90g{\cdot}L^{-1}$ sucrose. The culture conditions were $24{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with 16 hour daylength using fluorescent lamps and maintained at $22{\pm}2^{\circ}C$. The virus-free bulblets were grown for one to three years in the greenhouse and transplanted to the field in October or March. Virus infection rates were investigated by direct tissue blotting immunobinding assays and measurement of chlorophyll and protein contents. Virus-free plants could be obtained from the 5th subculture of micro-scales in L. lancifolium and L. maximowitzii or from primary culture in L. dauricum and L. distichum. LSV-free plants were reinfected during bulb production in the field. Reinfection rates were higher at older bulb ages and under higher planting density. The plants planted in October and at inland Gyeongsan had higher infection rates than those planted in March and at coastal area Pohang. The reinfection rate of L. maximowitzii was higher than those of L. dauricum and L. lancifolium. The LSV-infected plants had lower chlorophyll contents and unchanged protein contents compared to virus-free plants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.76-90
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• 1993

To clarify the relations between photoperiodism and x-organ of eyestalks to the control of gonadal maturation in a freshwater prawn, Macrobrachium nipponense, the present investigation was performed with following examinations: 1) the influence of water temperature and daylength on the control of gonadal maturation, 2) the effect of eyestalk ablation on the gonadal maturation, 3) the seasonal variation of histology of MEX-organ (medulla externa X-organ) in the eyestalk. In previtellogenesis period (December${\sim}$March) and vitellogenesis period (April${\sim}$May), gonadal maturation was considerablely influnced by water temperature. In these periods, GSI increased and gonads were matured with water temperature rising without regard to photoperiod conditions (12L/12D and 15L/9D). In spawning period (June${\sim}$August), however, gonadal maturation was influenced by photoperiod condition. While high value of GSI was kept at long photoperiod regime (15L/9D), GSI was decreased at short photoperiod regime (12L/12D). In resting period (September${\sim}$November), no rematuration was occurred at all the experimental regimes combinated with water temperatures ($16^{\circ}C,\;22^{\circ}C,\;28^{\circ}C$) and photoperiod (12L/12D, 15L/9D). Effect of X-organ which inhibite the gonadal maturation was stronger in resting period than that in previtellogenesis and ealy spawning periods by observations on the effectiveness of eyestalk ablation on the gonadal maturation. In MEX-organ of eyestalk, the number of neurosecretory cells of which size was over $20{\mu}m$ in diameter varied according to the reproductive cycle. The number of cells increased $77{\pm}12$ in resting period, and decreased $55{\pm}7$ in vitellogenesis period. Volume of Bellonci's organ, however, increased in vitellogenesis period in comparison with that in resting period.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.467-483
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• 1982

Leaflets of Allium sativum L. (garlic) and leaf scales Allium cepa L. (onion) were cultured on the Murashige and Skoog(MS) medium to study the effects of plant growth regulators, temperature and light on the formation of shoot and root. And also, the potentiality of shoot or root formation of tissues in accordance with the leaf age and the region was discussed. In the experiment with garlic, the formation of shoot and root was more effective on the medium containing $BA\;2mg/{\ell}$ and $NAA\;1mg/{\ell}$ and it occured on the basal region of outer leaflets. The shoot formation was more effective at $20^{\circ}C$ than $28^{\circ}C$ under 16-hour daylength, and it was more effective in darkness than light condition at $28^{\circ}C$. The results of shoot and root formation on the new cloves of garlic harvested in 1982 were similar to those the old cloves of garlic harvested in 1981. In the experiment with leaf seales of onion, when the tissues of dormant leaf scales of onions harvested in 1981 were explanted on the MS medium, a few shoots were formed on the medium containing $BA\;2mg/{\ell}$ and $NAA\;1mg/{\ell}$. In this case,there were no differences on the shoot formation among the age and region of leaflets. On the culture of leaf scales, the shoot was not formed on the leaf scales located at outer or middle region, but it was formed on the medium containing BA accompanied with NAA at inner scales. On the medium complemented with BA alone, the tissues were not differentiated, but on the medium complemented with NAA, the callus was formed from tissues and then the root was formed through the callus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.