• Horticultural Science & Technology
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• v.28 no.6
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• pp.942-947
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• 2010

In the present study, pollen tube growth and fruit set in Asian pear ($Pyrus$ $pyrifolia$) were examined upon the mechanical damage on the stigma and style following the artificial pollination. When the upper middle part of style was cut off at 48 h after the artificial pollination, pollen tube grew to the middle of the style and the subsequent pollen tube elongation and fruit set normally occurred. When the style was cut off before the pollen tube reached the middle of the style, however, no pollen tube elongation and fruit set occurred. With the pollen tube elongation through the style, callose plugs at the basal part of the pollen tube were formed to the direction of the elongation at regular intervals. When the upper part of pollen tube attached pollen grain was cut off, however, callose plugs were formed defectively in the pollen tube, and the pollen tube opened and lost their turgor pressure. These facts might be the reason for the ceased or delayed pollen tube elongation and ultimately the failure of the fertilization.

• Fisheries and Aquatic Sciences
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• v.16 no.1
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• pp.15-23
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• 2013

Normal embryonic development at a constant temperature ($18^{\circ}C$) has been described for the Siberian sturgeon Acipenser baerii (Acipenseriformes). Hormone-induced spawning and artificial insemination were performed to prepare embryonic batches for embryologic examination. After insemination, early cleavages of the Siberian sturgeon embryos continued for 7 h post-fertilization (HPF), showing the typical pattern of uneven holoblastic cleavage. Blastulation and gastrulation began at 9 HPF and 19 HPF, respectively. Epiboly formation (2/3 covered) was observed at 25 HPF during gastrulation. Neurulation was initiated with the formation of a slit-like neural groove from the blastopore at 33 HPF. During neurulation, the primary embryonic kidney (pronephros) and s-shaped heart developed. The embryos underwent progressive differentiation, which is typical of Acipenseriform species. A mass hatching was observed at 130 HPF, and the average total length of the hatched prolarvae was 10.5 mm. The hatched prolarvae possessed a typical pigment plug (yolk plug). The results of this study are valuable not only as a reference guide for the artificial propagation of Siberian sturgeon in hatcheries but also as the basis for the derivation of developmental gene expression assays for this species.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.31-38
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• 2010

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.297-300
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• 1996

In male reproducible health and fertility and IVF(in-vitro fertilization), semen analysis has been most important. But the traditional tools for semen analysis are subjective, imprecise, inaccurate, difficult to standardize, and difficult to reproduce mainly due to their manually oriented operations. The purpose of a morphometric analysis of sperm is to microscopically type-classify spermatozoa cytologically according to their morphology of heads. Until now, the strict criteria method has long been used in clinic to discriminate normal spermatozoa from abnormal ones. This method cannot classify the diverse groups of abnormal spermatozoa in detail and shows variations in inter-operators and intra-operator In this paper, we developed a new method of a sperm morphometric analysis using artificial neural networks which are widely used in pattern recognition and image processing.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.205-213
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• 2022

The experimental fish transplanted from China in 2015 was used after seedling production and cultivated. Breeding management for experiment was carried out from October 2020 to February 2021. Also, it succeeded in inducing artificial maturation three to four months earlier than wild broodstock and secured good quality fertilized eggs. The average size of fertilized eggs was 1.22 mm, at 20℃ Blastodisc (15 minutes post-fertilization), 2 cell (50 minutes), 4 cell (1 hours), 8 cell (2 hours), 16 cell (2 hours and 30 minutes), 32 cell (2 hours and 50 minutes), morula (3 hours), blastula (8 hours), gastrula (15 hours), skull formation (20 hours), organ formation (30 hours) and hatching yolk larvae stage (35 hours). The total length of the just hatched larvae were 2.50 ± 2 mm, and then gain growth of 42.5 mm by 60 days, reaching 45 ± 5 mm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.43-55
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• 1976

Fertilization and early development of turbo cornutus was studied based on the samples which were collected in Yeosu area. Particular emphasis was paid on induction of artificial spawing, fertilization rate, preembryonic development, the growth of the early larva and larval survival to various salinity. Among the various methods for induction of artificial spawning which have been tested for the present study, drying by exposure to air is the. most efficient, and percentage fertilization rate was $83.8-96.4\%$. The diameter of fertilized eggs was $0.182{\pm}0.0028mm$; and the diameter of egg membrane was $0.245{\pm}0.093mm$. Under the temperature range of $20.6-25.4^{\circ}C$ the larvae hatched out after 11:05-11:15 hours of fertilization. After 3.0-3.5 days of fertilization the planktonic larvae begand to settle, and the settlement terminated within 5 days. During the period of 150 days of early culturing the diameter growth of shell(M) and the diameter of shell aperture(A) was formulated as follows: $$1972\;M=0.33e^{0.02070D}$$ $$A=0.19e^{0.02282D}$$ $$1973\;M=0.32e^{0.02282D}$$ $$A=0.16e^{0.02596D}$$ During the same period of early culturing the relative growth of shell diameter and the diameter of shell aperture was formulated as follows : 1972 A=0.6478 S-0.1575 1973 A=0.5897 S-0.0515 After 11 days of larval hatching $0.02-0.18\%$ of planktonic larvae settled. After 150 days of settlement the survival rate of the early shells was $7.4-21.6\%$. Under the temperature range of $21.0-22.7^{\circ}C$ the optimum salinity range for the development of egg and the planktonic larvae was $30-35\%_{\circ}$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.420-424
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• 2006

This experiment was conducted to elucidate the basic physiological phenomena of pollination and fertilization for breeding in perilla (Perilla frutescens) through different 6 varieties derived from 2 genera under 4 temperature conditions at day and night. The pollen germination was observed after 30 minutes and pollen tube reached the lower part of pistil after 1 hour from artificial pollination. Seed formation was affected by temperature condition and a variety. The early maturing variety 'YCPL 25' showed a poor seed formation rate under the night temperature below $15^{\circ}C$, but the late maturing variety 'YCPL263' did not lowered even though the night time temperature was $10^{\circ}C$. The function of pistil was long maintained under the low temperature from the fact that if the live pollen pollinate artificially to the flower that does not form seed under low temperature, fruiting was made. Pollen was created and pollen tube was developed in the time of petal becomes bigger than calyx in five varieties, 'YCPLl77-1' etc. However, pollen was made and pollen tube was made only 71% in a green chajogi 'YCPL205-1'. These physiological phenomena of pollination and fertilization could be applicable to the emasculation and an effective breeding in perilla.

• Journal of Aquaculture
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• v.20 no.3
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• pp.160-167
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• 2007

Embryonic and pre-leptocephalic larvae development of the eel, Anguilla japonica, are described following natural fertilization in the indoor tank of $23^{\circ}C$ water temperature. Following a routine hormone treatment technique for the brood stock, female eels were artificially matured by weekly intramuscular injections of salmon pituitary extracts (SPE) at a dosage of 20 mg/kg body weight (BW) for a total of 10-14 doses to induce ovarian maturation, while male eels received weekly intramuscular injections of human chorionic gonadotropin (HCG) at a dosage of 1 IU/g BW for a total of 6-10 doses to induce testicular maturation in a separate aquarium and induced natural spawning. Fertilized eggs of about 1.0 mm in diameter were pelagic and showed a typical discoidal cleavage. Hatching occurs 38 hrs after fertilization at a water temperature of $23^{\circ}C$. The newly hatched larvae measured about 3.0 mm in total length and the number of myomeres averages 42. Their mouths and anuses were opened at 4.5 days and the yolk sacs of the pre-leptocephalic larvae were almost absorbed at 6.5 days after hatching. Pre-leptocephalic larvae survive for 14.5 days. At this time they are $5.87{\pm}0.25mm$ in total length and have about 98 myomeres. However, morphological characterization of embryonic and pre-leptocephalic larvae were not different between natural fertilization and artificial fertilization by the dry method.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.193-201
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• 1999

In this study we determined fertilization processes and developmental ability of porcine oocytes following injection of round spermatid in the presence of artificial activation. Electrical stimulation at 3 h before spermatid injection significantly increased the incidence of normal fertilization as compared to those following injection without stimulation or with stimulation immediately after injection. The incidences of two pronuclear formation and apposition were not different in oocytes between following intracytoplasmic spermatid and spermatid nucleus injection. Indirect immunocytochemistry and laser scanning confocal microscopy study revealed that micro tubules were organized from the oocyte cortex following round spermatid injection, and this seemed to move both male and female pronuclei into the oocyte center. Paternal mitochondria which are introduced with spermatid have been observed up to 4-cell. Our study indicated that either round spermatid or it's nucleus can be used to produce viable bovine embryos by injection into unfertilized oocytes.

• Journal of Aquaculture
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• v.10 no.1
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• pp.25-32
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• 1997

Develoment precess and characteristics of eggs of the geoduck clam, Panope japonica are reporting in this study. Eggs and sperm were excised from gonad, artificially fertilized in an aquarium, reared under various temperature regimes, and record and record the larval period and the time need to reach a certain larval stage from ferilization. Unfertilized eggs of P. japonica appeared to be oval with a mean diameter of $70\mu$m and they became spherical after fertilization. The eggs of P. japonica can be classified as demersal. At a constant water temperature of $ 11^{citc}C$, it took 4 hours form fertilization to become four-cell stage, two days to become trochophore larvae, three days to become D-shape larvae, twenty-three days to become umbo stage, and thirty-six days to become fully grown veliger ready form settlement. A negative correlation was observed between the water temperature and the larval period of P. japonica. From fertilization to D-shape larvae, it took five days at 8$^{\circ}C$, while it was only two days to become D-shape larvae at $ 17^{citc}C$. Time required to D-shape larvae from fertilization was proportional to temperature, and the relationships were expressed as follows : To 8-cell stage, 1/t=0.0209 w-0.1167 (r=0.9967) To blastula stage, 1/t=0, 0055 w-0.0192 (r=0.9825) To trochophore stage, 1/t=0.0034 w-0.0155 (r=0.9907) To D-shape larvae stage, 1/t=0.0014 w-0.0023 (r=0.9843) (t, time in hours ; w, water temperature) Bioligical minimum temperature for egg development was calculated as 3.82$^{\circ}C$ in average.