• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.13 no.3
• /
• pp.95-101
• /
• 1980

Optical properties were studied at the fishing ground of anchovy in the southern part of Korea based on seven oceanographic stations from May to August and November to December, 1977. Submarine daylight intensity was measured at intervals of 1m depth in the upper 30 m layer by the underwater luxmeter (Toshiba # 9). The absorption coefficient of the sea water ranged from 0.066 to 0.619 (mean 0.21) for six months. The transparency ranged from 2.6 to 16 meters (mean 8.4m). The relationship between absorption coefficient (n) and transparency (D) was k=1.70/D. The mean water color in this area was 4.8 $(3\~10)$ in Forel scales. The rates of light penetration for daylight at four different depths were computed with reference to the surface light intensity. The mean rates of light penetration were $69.38\%(25.43\~88.10\%),\;30.35\%\;(4.38\~59.46\%),\;12.53\%\;(0.75\~33.51\%),\;5.7\%(0.18\~20.27\%)$ at depths of 1, 5, 10 and 15 m respectively.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.10a
• /
• pp.52-52
• /
• 2019

산채는 사람에 의하여 개량 육성되어 논밭에서 재배하고 있는 농작물과 달리 자연 그대로 산야에서 자생하는 식물 중 식용으로 가능한 것을 말한다. 우리나라 산야에는 480종의 식물이 식용으로 이용될 수 있다고 하나 현재 전국에서 재배하고 있는 작목은 36종으로 추정되며, 앞으로도 80여 종이 개배 가능한 작물로 추정된다. 산채류의 이용형태별 생산가능시기는 3~5월의 생채 생산과 6~7월의 건채 생산으로 소비자의 기호에 부합하는 신선 생채의 소비한계는 제한되어 있기 때문에 재배유형별 생채 수량검정을 통해 수확시기 연장 및 재배품목을 다양화 시킬 필요 있다. 이에 본 시험은 산채류 재배유형별 수확기간을 구명하고자 표고 500 m의 전북 남원시 허브산채시험장에서 2018년 5월 말 갯기름나물 등 15 종을 노지와 하우스에 정식하여 각 작물의 생육특성, 수확한계기 등을 조사하였다. 1년차 지상부 생육특성을 조사한 결과 참취, 개미취, 섬쑥부쟁이, 질경이, 갯기름나물, 두메부추, 돌단풍, 참당귀의 경우 초장, 엽장 등은 노지보다 하우스에서 높은 편이었고 생존율은 비슷하거나 하우스에서 더 높은 경향을 보였다. 우산나물, 단풍취의 생존율은 하우스에서 더 높았으나 생육 초기 엽소현상으로 인해 1년차 생육은 노지, 하우스에서 둘 다 저조하였고 곤달비, 어수리, 곰취, 눈개승마의 경우 노지에서는 7월 중순이후 지상부가 전부 고사하였으나 하우스에서는 생존율이 상대적으로 양호하여 11월 상순까지 후기 생육을 하였다. 2년차 산채류 출현기 조사한 결과 하우스 재배에서 산마늘이 2월 중순으로 가장 빨랐고 갯기름나물, 곤달비 등 10종이 2월 하순에 출현하였으며 참당귀 3월 상순, 단풍취 및 우산나물 3월 중순, 돌단풍이 가장 늦은 3월 하순에 출연하였다. 생체수확 시기는 갯기름나물, 눈개승마, 산마늘, 두메부추, 섬쑥부쟁이는 3월 중순부터 가능했고 곤달비 등 12개종은 3월 하순, 우산나물은 4월 상순, 돌단풍은 4월 중순으로 가장 늦게 생체수확이 가능했다. 노지 재배의 경우 산마늘과 눈개승마가 3월 중순으로 가장 빨랐고 갯기름나물 등 10종이 3월 하순에 출현하였으며 돌단풍, 참당귀, 단풍취가 4월 상순으로 가장 늦은 출연을 보였다. 생체수확 시기는 눈개승마와 산마늘이 4월 상순으로 가장 빨랐으며 갯기름나물 등 10종이 4월 중순부터 가능했고 돌단풍, 참당귀, 단풍취가 4월 하순으로 가장 늦었다. 수확한계기 조사 결과 눈개승마, 산마늘, 우산나물은 하우스 및 노지재배에서 20일정도로 가장 짧았으며 그 외 작물들은 계속적으로 수확이 가능하였으나 6월 상순 이후에는 품질이 나빠져 생체상품으로서 가치가 없었다.

• Journal of Bio-Environment Control
• /
• v.4 no.2
• /
• pp.211-222
• /
• 1995

This experiments were carried out to investigate the growth responses of spinach to temperature controlling by shading treatments at different times during the summer, and the effects of environmental parameters on the growth and yield were evaluated. The fourth cultivation was showed maximum temperature at air temperature of 33.1$^{\circ}C$ and soil temperature of 28.6$^{\circ}C$, followed by third, second, fifth and first cultivation. Among the tested temperature decreasing by shading, shading with silver - coated PE film strips was the most effective in lowering greenhouse air temperatures by showing 1.1$^{\circ}C$ decrease as compared to the outside air temperature and 3.1$^{\circ}C$ decrease as compared to the air temperatures inside the non-shaded PE house and 2.3$^{\circ}C$ decrease as compared to the air temperaturese shading with black- coated PE film strips, the soil temperature was showing 2$^{\circ}C$ decrease in both shading treatments than non-shaded PE and outdoor. In first cultivation, difficult cultivated as compared to others period owing to bolting of spinach. This first period was cultivated used two domestic cultivars and six imported cultivars, significantly better growth and higher yield of spinach were recorded in glory, manchuparuk and sunlighr cultivars. The effectiveness of shading on spinach, as expressed by the crop yield increase, was the highest in the planting from July 1 to August 24.

• Korean journal of applied entomology
• /
• v.50 no.4
• /
• pp.283-288
• /
• 2011

Occurrence of Scrobipalpa salinella (Zeller) was investigated on glasswort in Shinan, Jeonnam and Kimjae, Jeonbuk from 2010 to 2011. The occurrence of S. salinella observed four times in a year. Adult stages of S. salinella in two areas occurred from mid-April to late September. The peak times of 1st, 2nd and 3rd generation adults of S. salinella was observed on early May, mid-June, late July (in Kimjae) to early August (in Shinan) and early September, respectively. And larval stages of S. salinella occurred from late May to late August. The peak times of development of 1st, 2nd and 3rd generation larvae of S. salinella was observed on mid-June, mid-July and mid-August, respectively. However, the 4th generation larvae began to occur in mid-September but didn't damage in glasswort. Among the distances from the bank of glasswort field (3, 6, 9 m) and periods of damage (Jun. 16, Jul. 7, Aug. 12), larval density in 3 m distance from the bank in 1st damage season (Jun. 16) was high which resulted to severe damage. Damage of 2nd and 3rd generation larvae was progressed both density of larvae and levels of damage.

• The Korean Journal of Malacology
• /
• v.31 no.3
• /
• pp.171-178
• /
• 2015

The reproductive ecology of freshwater bivalve, Unio douglasiae in Lake Uiam were examined from March 2014 to February 2015. The gonads distributed in reticular connective tissue, the dioecious clams take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The gonad index (GI) began to increase in April, reached the maximum value in July and to decrease in August. The reproductive cycle of U. douglasiae can be divided into five successive stages: multiplicative stage (November to January), growing stage (February to March), mature stage (February to May), spawning stage (April to September), recovery stage (August to December). The spawning periods were from April to September, and the main spawning occurred between April and July. The shell length at 50% group maturity was estimated to be 29.4 mm.

• Journal of Aquaculture
• /
• v.11 no.4
• /
• pp.475-485
• /
• 1998

To clarify annual reproductive cycle of Koran dark sleeper, odontobutis platycephala, we examined the seasonal changes of gonadosomatic index(GSI), testicular development stages and sex steroid hormones in blood from December 1995 to November 1997. Testis was podlike shape from July to October, and tadpole-like shape from November because of its expanded posterior part. GSI was 0.14~0.18 from July to September and increased to $0.43{\pm}0.04$ in October and then was not changed significantly until February. GSI was reincreased to $0.52{\pm}0.09$ from March and then was kept at similer levels until May, but fell down to $0.28{\pm}0.05$ in June. As results of histological observation, testis was divided into 3 parts(anterior, boundary, posterior) in the development progress of germ cells. In July, the testis was composed of only spermatogonia without seminiferous tubules in most fishes. In the anterior part of testis, the ferquency of spermatogenesis stage seminiferous tubules appearing in August was more than 80% from September to December. decreased gradually from January to March and drastically in April, and then disappeared in June. The frequency of spermiogenesis stage seminiferous tubules appearing in December, increased gradually from January to March and drastically to 80% in April, and reached to 90% the highest levels of the year in June. Post-spawning stage seminiferous tubules did not appear throughout the year. The frequency of spermatogonia was 100% and 65% in July and August, and less than 20% in the rest period of the year. In the boundary part, the frequency of spermatogenesis stage seminiferous tubules appearing in August increased from September and reached to 82% in November, decreased from December, adn disappeared in March. The frequency of spermiogenesis stage seminiferous tubules appearing in November was less than 18% until February, and increased to 29%~57% from March to June. The frequency of post-spawning stage seminiferous tubules appeared 12%~25% only from March to June. The frequency of spermatogonia was 100% in July, decreased to 85% in August and 10% in November, and increased gradually from December to 50% in April, and decreased again from May to June. In the posterior part, seminiferous tubules with some seminiferous tubules increased drastically 80%~85% in August and September, decreased drastically from October to November and remained below 10% until February, and disappeared after March. The frequency of spermiogenesis stage seminiferous tubules appearing in August increased sharply from October and reached to 75% in November. decreased to 15% in December and no significant changes until March, and disappeared after April. The frequency of post-spawning stage seminiferous tubules appearing very early in November increased to 82% in December and 85%~95% until June. The frequency of spermatogonia was 100% in July, decreased drastically to 15% in August, disappeared from October to Mrch, but reappeared from April and kept at less than 10% until June. The blood level of testosterone (T) increrased gradually from August was $0.61{\pm}0.09 ng/m\ell$ in November, increrased drastically to $3.99{\pm}1.22 ng/m\ell$ in December and maintained at in similar level until March, and decreased to $0.25{\pm}0.14 ng/m{\ell} ~ 0.17{\pm}0.13ng/m{\ell}$ in April and May and no significant changes until July (P<0.05). The blood level of 17, 20 -dihydroxy-4-pregnen-3-one $ng/m{\ell}$in the rest of year without significant changes(P<0.05). Taken together these results, the germ cell development of testis progressed in the order of posterior, boundary, anterior part during annual reproductive cycle in Korean dark sleeper. The testicular cycle of Korean dark sleeper was as follows. The anterior part of testis : i.e. spermatogonial proliferation period (July), early maturation period (from August to November), mid maturation period (from December to March), late maturation period (from April to May) and functional maturation period (June) were elucidated. The boundary of testis, i.e. spermatogonial proliferation period (July), early maturation period (from August to October), mid maturation period (from November to February) and the coexistence period of late maturation, functional maturation and post-spawn (from March to June) were elucidated. The posterior of testis, i.e. spermatogonial proliferation period (July), mid maturation period (from August ot September), late maturation period (October), functional maturation period (November) and post-spawn period (from December to June) were elucidated. It was showed that the changes of sex steroid hormone in blood played a important roles in the annual reproductive cycle of Korean dark sleeper.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.4 no.2
• /
• pp.136-143
• /
• 1999

To understand the growth of attached microalgae to the immersed artificial surfaces in seawater with exposure time, chlorophyll a (chl a) concentration and abundance of attached microalgae to glass slides, and primary productivity and chl a concentration on coverglasses were investigated in Incheon Harbour in May, June 1996 and January-February 1997. Chl a concentrations of microalgae and abundances of diatoms attached to glass slides reached 62.5 mg chl a $m^{-2}$ and $144{\times}10^3$ cells $cm^{-2}$, respectively, during the study period. Chl a concentrations increased with exposure time, and they were significantly correlated with the abundances of attached diatoms ($r^2=0.79$, p<0.001). The chl a concentrations of attached micro algae on coverglass reached the maximum values of 31.1 mg chl a $m^{-2}$ and 65.4 mg chl a $m^{-2}$, and then decreased in May, June 1996. But in January-February 1997, the chl a concentration increased continuously up to 98.9 mg chl a $m^{-2}$. The primary productivity reached the maximum values of 63.1 mgC $m^{-2}\;h^{-1}$, 347.0 mgC $m^{-2}\;h^{-1}$ and 78.3 mgC $m^{-2}\;h^{-1}$, respectively, in May, June and January-February. The primary productivity in May and June varied in accordance with chl a concentrations. But in January-February, the primary productivity decreased from 26 days of exposure while chl a concentration continued to increase. Two cases that primary productivity decreased abruptly seemed to be caused by decrement of chl a and light specific $P^B$ (chl a specific primary productivity) (May and June) and by decrement of light specific $P^B$ due to photoinhibition (January-February). The results of present study indicated that chl a concentrations and the primary productivity of microalgae attached to artifical surfaces immersed in seawater would expedite analysis of dynamics of biomass and physiological status of attached microalgae during biofilm formations.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.9 no.1
• /
• pp.7-14
• /
• 1989

This experiment was carried out to determine the seasonal herbage production and utilization during the growing season of pasture on the forest (shading 30%). Plant height, leaf area index(LAl), dry matter(DM) production and distribution, chemical composition, in vitro dry matter digestibility(IVDMD), herbage utilization percentage and chewing efficiency were investigated using the Corridale sheep. Experimental field was treated by one plot design(3 rep.) and performed from 1987 to 1988 at Chungnam National University, Daejon. The results obtained are summarized as follows: 1. The highest plant height and LA1 were observed in May(35.0 cm, 4.89), followed by April(28.0 cm, 4.23), while the plant height and LA1 in October (13.0 cm, 0.49) showed very low. 2. During the growing season, about 58.3 % of annual DM production (7240 kg/ha) was produced during the spring (April, May and June) and the highest DM production was obtained in May (2040 kg/ha), which was more than 28.2 % of total DM production. However, DM production in July and August was about 24.2 % and those in September and October (17.5 %) was very low, but the difference of DM production from June to September was small. 3. The maximum DM production per day (65.8 kg/ha) was observed in May, followed by June (28.7 kglha), while DM production per day in October (16.5 kg/ha) showed very low (p <0.01). 4. Crude protein content and IVDMD of herbage samples during the spring (April, May and June) were higher, while crude fiber, ADF, and NDF content were lower in an summer growth herbage samples (July and August), but autumn growth herbage samples was intermediate. Crude ash content and IVDMD of collected herbage samples were slightly more, while crude fiber, ADF and NDF content were slightly less than offered and residued herbage samples during the growing season. 5. The maximum DM intake per metabolic body size was observed in May(68.9 g), followed by October (66.7 g), while very low in August (52.5 g). Significant positive correlation (p <0.05) was found between DM intake and IVDMD. 6. Herbage utilization percentage was very high in April (83.4 %), while very low in August (64.0 %). The percentage of annual herbage utilization was about 75.5 %. 7. The maximum ruminating and chewing efficiency of herbage samples were observed in May, followed by October, while very low in August.

• Food Science and Preservation
• /
• v.12 no.6
• /
• pp.529-533
• /
• 2005

The respiratory characteristics of Korean fresh ginseng were investigated from the aspect of picking season, size, and storage temperature and period to get basic data for extension of shelf-life. The respiration rate of fresh ginseng picked in March was 4.09 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$. It was gradually increased to August, 7.88 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and then decreased continuously until November. Although the rate of fresh ginseng was different by picking season, the respiration quotient showed the same level, $1.03\~1.07$. Respiration rate by size was ranged from 3.47 to 5.69 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and smaller in the size was higher in the rate. $Q_{10}$ value of fresh ginseng was $2.68\~2.88$ when the temperature increased from $0^{\circ}C\;to\;10^{\circ}C$ and $1.77\~2.16$ from $10^{\circ}C\;to\;20^{\circ}C$, and it was slightly different by picking season. At the beginning of storage the respiration rate was 7.0 mL $CO_2/kg{\cdot}hr$ and it was .decreased to 3.38 mL $CO_2/kg{\cdot}hr$ after storage for 90 days at $0^{\circ}C$.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.20 no.1
• /
• pp.75-87
• /
• 2018

This study was carried out to investigate the effects of planting time on the survival rate and growth. Ilex cornuta Lindl., I. aquifolium 'Silver Queen', Ardisia pusilla 'Variegata', and Rhododendron indicum(Satsuki azalea) were planted in pottery pot six times such as April 1, June 1, July 1, August 1, October 1, and December 1 in 2017. The survival rate of I. cornuta Lindl. planted in April, October, and December was 100%, whereas the survival rates were 90% in June, 50% in July, and 60% in August, respectively. The survival rates of I. aquifolium 'Silver Queen' and R. schlippenbachii were also shown about 60% in July and 70% in August, which were lower than in the other planting times at 100%. However, the survival rate of A. pusilla 'Variegata' was shown 100% in the all planting times. The growth rates of plant length, plant height or leaf length or any others of I. cornuta Lindl. were shown 20.0%, 15.5% and 16.5% planted in June, July, and August, respectively, while those planted in April, October and December were 3.2%, 12.3% and 10.7% respectively. Similarly, the growth rates of leaf numbers and plant length of I. cornuta Lindl., A. pusilla 'Variegata', and R. indicum(Satsuki azalea) planted in summer season from June to August for all plat (not only leaf numbers and plant length in was facilitated, while the growth was restrained in planting for spring or autumn. Therefore, the plantation during summer is better for increasing the survival rate and promoting the growth.