• 한국수산과학회지
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• 제38권2호
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• pp.112-117
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• 2005

Sargassum fulvellum (Turner) C. Agardh, an edible brown alga is farmed commercially by sexual reproduction and vegetative regeneration. Investigations were made on the phenology, abundance and maturity of reproductive structures in mature fronds, egg release and young germling development under different light conditions (20, 50, 80 and $100{\mu}mol/m^2/s$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$). Monthly sampling was carried out by SCUBA diving at Chungsando on the southwestern coast of Korea from September 2002 to August 2003. The Maximum length of thalli was $104.6{\pm}20.7{\cal}cm$ in March 2003 when the water temperature was $9.0^{\circ}C$ and minimum was $0.8{\pm}0.5{\cal}cm$ in June when the water temperature was $19.5^{\circ}C$. Receptacle formation was observed from February to April. The peak period of egg release for this alga was in April when the water temperature was about $10^{\circ}C$ in nature. In the culture regimes of temperature and irradiance, the egg release of the excised female receptacle was highly affected by temperature. The maximum rate of egg release was $96.7{\pm}5.8{\%}$ under $20^{\circ}C$ and $80{\mu}mol/m^2/s$. The maximum length of young germlings was $3.9{\pm}0.2{\cal}mm$ after 35 days culture under $15^{\circ}C$ and $80{\mu}mol/m^2/s$.

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.34.1-34.13
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• 2018

Sexual maturity ($L_{50}$), the length at which 50% of fish in a size class are mature, is a key aspect of domestication of new fish species because it guides the procedure for identification of appropriate broodstock size for artificial spawning. In this study, the $L_{50}$ was determined for 1083 Barbus altianalis samples obtained from Lake Edward and the Upper Victoria Nile. Gonads of freshly killed samples were examined macroscopically and verified with standard histological procedures for the maturation stages that were used to determine $L_{50}$. Oocytes and spermatogenic cell sizes were compared for fish obtained from both water bodies. Results indicated that there were no variations in macro gonad features observed for fish from Lake Edward and Upper Victoria Nile. Similarly, there were no significant differences in oocyte sizes (P > 0.05) between the two populations but significant differences in spermatogenic cell sizes were noted (P < 0.05) except for spermatozoa (P > 0.05). This however did not suggest peculiar differences between the two populations for staging the gonads. Consequently, no staging variations were suggested for both populations in determination of $L_{50}$. Sexual maturity was found in the same class size of fork length (FL) 20-24.9 cm and 35-39.9 cm for males and females from both water bodies, respectively. At this FL, however, males were too small, and for good selection of vigor broodstocks for spawning and conservation purposes, they are better picked from class size of 30-34.9 cm FL and above. These findings were crucial for integration of appropriate breeding size in spawning protocol by farmers and fisheries scientists conserving wild B. altianalis populations.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.21-21
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• 2014

A edible mushroom, Hypsizygus marmoreus is commercially cultivated in Northeast Asia. Japan's annual production is 110,000ton or more. Since 2002, cultivation is expanded in Korea. To investigate the morphological, cultural and microscopic characteristics of Hypsizygus marmoreus, 109 isolates were collected from Korea and other countries. Clamp connection, chlamydospore and arthrospore were present in all tested isolates of H. marmoreus except HYM-002 and HYM-004. Also pilealtrama, gilltrama, basidia, basidiospore and cystidia of fruiting body were no difference among the isolates in the present investigation. Morphological characteristics of fruiting body was that color of pileus was brown and white, irregular as marble, the average size 12~22mm and stipes was $46{\sim}91{\times}6{\sim}10mm$. Isolates HYM-031, HYM-047 and HYM-109 formed grayish-brown pileus with a faint pattern. Molecular analysis with RAPD and ITS rDNA sequence analysis were also performed to check the genetic relationships among H. marmoreus isolates. Based on the RAPD analysis using the URP-PCR, all isolates of H. marmoreus were clustered into large 3 groups but more than 90% showed high similarity. In addition, morphological and geographical differences have been classified as an independent cluster. The brown and white strains enclosed in same cluster. So genetically no significance difference was observed between these two strains. ITS gene sequences of 16 selected isolates which were 640 bp long, were aligned and compared. The similarity in ITS sequence was 94.8 to 99.1% among tested isolates and the H. marmoreus isolates in GeneBank. In conclusion the tested isolates were H. marmoreus. Morphological and molecular observations proved that all tested isolates were belonging to H. marmoreus. For the stable artificial cultivation, composition of optimum media, mature period and light condition were established. Optimal formula of artificial cultivation medium was Douglas sawdust: corn cob: soybean meal: wheat bran = 40:30:15:15. In addition, 7% rice bran and 3% yellow sucrose was the most effective composition for spawn's liquid medium. For the maturation of the isolates was favorable for growing for 20 to 30 days at $25^{\circ}C$ and the LED lights in mixture of white and blue was good for growth period. For effective growth, the temperature, humidity and aeration control in every step was important.

• Fisheries and Aquatic Sciences
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• 제24권12호
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• pp.437-445
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• 2021

Roughscale sole (Clidoderma asperrimum) is only wild caught because basic reproductive research on this species is lacking and gamete production in an artificial setting has not been successful. Exogenous hormone treatment has been used to induce gonadal maturation and final spermiation in wild-caught individuals. In this study, the effects of an exogenous hormone on spermiation in roughscale sole was investigated by implanting different concentrations of a salmon gonadotrophin-releasing hormone analog (sGnRH; 0, 25, 50, and 100 ㎍/kg body weight) into male fishes. The control group did not produce sperm after 21 days post-implantation, and the duration of spermiation was shorter compared to the other groups. The spermiation period and milt amount differed among the hormone-treated groups according to the hormone concentration used. Milt volumes in the groups treated with 25 and 100 ㎍/kg sGnRH increased compared to the control group, whereas exogenous hormone treatment had no effect on the movable sperm ratio. The spermatocrit was high at the beginning of spermiation in all groups and then tended to decrease gradually over time except in the experimental group treated with 100 ㎍/kg sGnRH. Plasma levels of testosterone, 11-ketotestosterone, 17α, 20β-dihydroxy-4-pregnen-3-one were not significantly affected by the sGnRH treatments. Our results demonstrate that it is possible to prolong the spermiation period and increase milt volume by treating male roughscale soles with an exogenous hormone. In addition, the artificial hormone treatment did not affect sperm motility.

• Plant Biotechnology Reports
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• 제3권3호
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• pp.251-257
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• 2009

Embryogenic callus was obtained from bulb segments of Iris pseudacorus on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid (2,4-D) alone or in combination with kinetin. When early globular somatic embryos were subcultured onto MS medium with $4.52{\mu}M$ 2,4-D, high frequency of somatic embryogenesis was obtained. Deprivation of 2,4-D was required for maturation. Mature somatic embryos had an elongated scutellum with a notch on the base of scutellum. Separation of embryos from embryo clusters was necessary to enhance the frequency of germination. Germination was stimulated by separation of embryos from embryo clusters and transfer onto fresh half-strength MS medium with 3% sucrose. After acclimation in artificial soil in greenhouse for 2 months, 96.4% of plantlets survived.

• 농업과학연구
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• 제49권4호
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• pp.785-793
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• 2022

In this study, tomato maturity was estimated based on deep learning for a harvesting robot. Tomato images were obtained using a RGB camera installed on a monitoring robot, which was developed previously, and the samples were cropped to 128 × 128 size images to generate a dataset for training the classification model. The classification model was constructed based on convolutional neural networks, and the mean-variance loss was used to learn implicitly the distribution of the data features by class. In the test stage, the tomato maturity was estimated as a continuous index, which has a range of 0 to 1, by calculating the expected class value. The results show that the F1-score of the classification was approximately 0.94, and the performance was similar to that of a deep learning-based classification task in the agriculture field. In addition, it was possible to estimate the distribution in each maturity stage. From the results, it was found that our approach can not only classify the discrete maturation stages of the tomatoes but also can estimate the continuous maturity.

• 원예과학기술지
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• 제35권2호
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• pp.170-177
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• 2017

본 연구는 '거봉' 포도 재배시 야간의 빛 공해에 따른 피해를 예측하기 위하여 실시하였다. 야간 조사는 만개기부터 수확기까지 인공 광원으로 적색, 청색, 백색 램프를 사용하여 매일 오후 10시부터 오전 2시까지 4시간동안 조사하였다. 야간 조사는 생산량을 비롯하여 가용성 고형물 함량, anthocyanin, chlorophyll a 함량에 영향을 미치는 것으로 조사되었다. 무처리구의 가용성 고형물 함량은 $17.5^{\circ}Brix$로 야간에 빛을 조사한 적색광, 청색광, 백색광 처리구의 16.4, 16.2, $16.3^{\circ}Brix$에 비해 $1^{\circ}Brix$ 이상 높았으며, 과피의 anthocyanin 함량 또한 무처리구가 $4.08{\mu}g{\cdot}cm^{-2}$로 적색광, 청색광, 백색광 처리구의 3.14, 2.47, $2.82{\mu}g{\cdot}cm^{-2}$ 보다 높은 것으로 조사되었다. 반면에 chlorophyll a 함량은 무처리구가 $0.268{\mu}g{\cdot}cm^{-2}$로 적색광, 청색광, 백색광 처리구의 0.339, 0.345, $0.372{\mu}g{\cdot}cm^{-2}$와 비교하여 가장 낮았다. 결과적으로, 당의 증가와 anthocyanin의 축적 및 chlorophyll의 감소는 과실 성숙에 수반된 현상이라는 점을 고려할 때, 야간 조사는 '거봉'의 암기를 중단시켜 과실의 성숙 과정을 지연시키며 적생광 처리는 생산량 감소를 수반하였다. 따라서 광파장에 관계없이 야간조사에 의한 빛공해가 나타나는 것으로 확인되었으며, 가로등을 비롯한 야간 조명이 설치된 지역에 인접한 포도원의 경우 과실의 성숙이 불량해 질 수 있는 것으로 판단된다.

• 한국어류학회지
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• 제7권1호
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• pp.43-55
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• 1995

자연에서 3월 초순부터 6월 초순까지 산란기를 가지는 각시붕어, Rhodeus uyekii를 대상으로 이들의 생식주기 성립기구를 밝히고저 여러가지 광주기 및 수온 조건이 생식소의 활성과 퇴화 그리고 재성숙에 미치는 영향을 실험 적으로 조사한 결과는 다음과 같다. 춘계 생식소 활성화를 유도하는 환경요인은 수온상승이고 광주기는 영향을 미치지 않는 것으로 나타났으며, 이 시기의 임계수온은 $8^{\circ}C$ 이상이었다. 생식소 퇴화요인으로는 하계 고수온이며, 광주기의 영향은 없었다. 그리고 임계수온은 $20^{\circ}C$에서 $24^{\circ}C$ 사이에 존재하는 것으로 나타났다. 산란기 수온과 동일한 수온 범위가 존재하는 추계에 생식소가 성숙에 이르지 못하는 요인은 이 시기의 단일 광조건 때문이며, 다른 시기에는 나타나지 않았던 광주성의 발달을 볼 수 있었다. 추계 생식소 재성숙에 영향을 미치는 임계광주기는 12L과 13L 사이에 존재하며, 동계에서 춘계로 이행함에 따라 광주성은 사라지는 것으로 조사되었다. 이상의 결과에서 각시붕어의 성숙을 연중 제어할 수 있는 광과 수온범위는 수온은 $8^{\circ}C$에서 $20^{\circ}C$, 광조건은 13L 이상으로 생각된다.

• 한국양식학회지
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• 제20권3호
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• pp.160-167
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• 2007

극동산 뱀장어의 자연 수정란을 이용하여 $23{\pm}0.5^{\circ}C$의 여과 해수가 공급되는 실내수조에서 난발생과 pre-leptocephalus 자어발달을 관찰하였다. 친어 관리에 있어서 암컷은 연어 뇌하수체 추출물(20 mg/fish)과 수컷은 HCG (1 IU/g BW)를 매주 복강 주사하여 인위적인 성성숙 및 자연산란을 유도하였다. 수정란은 직경 1.0 mm 정도의 분리 부성란으로, 전형적인 반상분할(discoidal cleavage)을 통해 분할이 이루어졌다. 부화는 $23^{\circ}C$의 여과 해수에서 수정 후 38시간부터 개시되었다. 부화 직후의 자어는 전장 약 3.0 mm, 근절수는 평균 42개였다. 부화자어의 입과 항문은 부화 후 4.5일째에 열렸고, 난황은 부화 후 6.5 일째에 거의 흡수되었다. 자어는 14.5일 동안 생존하였고, 이때 전장 $5.87{\pm}0.25mm$, 근절은 98개였다. 그러나 수정란과 prelaptocephalus 자어발생의 형태학적 특징은 자연수정과 건식법에 의한 인공수정과 큰 차이점은 없었다.

• 한국패류학회지
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• 제18권2호
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• pp.83-91
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• 2002

자연산 바지락 (Ruditapes philippinarum) 개체군의 생식 주기와 수온-먹이섭이 및 절식조건에 따른 생식소 발달의 인위적 제어 결과를 조직학적 관찰에 의해 조사하였다. 곰소만 자연산 바지락 개체군의 생식소 발달에 따른 암수 개체의 생식주기는 초기활성기 (4-5월), 완숙기 (4-8월), 부분산란기 (5-10월), 퇴화 및 비활성기 (8-3월)의 연속적인 5단계로 구분할 수 있었다. 수온에 따른 생식소 발달의 인위적 제어 실험에서, 바지락은 저수온 (10$^{\circ}C$) 에 의해 억제되었다. 19$^{\circ}C$ 및 22$^{\circ}C$의 고수온에 노출시킨 실험구에서 생식소 발달은 고수온에 의해 촉진되었는데, 자연산 개체군의 것보다 약 1달 빠르게 나타났다. 고수온-먹이섭이 실험구에서, 작은개체 실험구의 생식소 발달 단계가 큰개체구 실험보다 더 빠르게 나타났으며, 저수온 (10$^{\circ}C$)의 것보다 더 빠르게 나타났다 (p=0.01). 암, 수 모든 개체들에서 고수온 (22-28$^{\circ}C$)-절식구 실험구의 생식소 발달관계가 고수온-섭이 실험구의 것들보다 더 빠른 것으로 나타났다. (paired sample t-test, p=0.004). 42일 경과 후 암컷과 수컷의 먹이섭이-고수온 실험구에서, 고수온-작은개체 실험구 조건이 큰개체의 생식소 발달보다 더 민감하게 나타났다. 그러나 저수온-수컷개체 실험구는 암컷 개체들의 실험구보다 반응이 좀 더 민감하게 나타났다. 전반적으로 고수온 실험구의 성적성숙이 저수온구보다 빠르게 나타났으며, 암수 개체 간에 유의한 차이를 보였다 (paired sample t-test, p=0.001). 42일 경과 후 절식 실험구에서, 고수온-수컷 큰개체 실험구의 생식소 발달이 고수온-암컷 큰개체 실험구의 것들보다 빠르게 나타났다. 그러나 작은 개체들의 생식소 발달 단계는 먹이섭이 실험구와 절식 실험구사이에 동일한 양상을 보였다. 산란 성기중 암수 개체들의 경우는 고수온-절식 실험구의 생식소 발달이 암컷과 수컷의 성 및 개체의 크기에 관계없이 고수온-먹이섭이 실험구의 것들보다 더 빠르게 나타났으며, 암수간 유의한 차를 보였다(paired sample t-test, p=0.004).