• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.469-475
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• 2013

In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in androgen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.

• 한국양식학회지
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• 제20권3호
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• 약학회지
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• 제45권2호
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• pp.190-204
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• 2001

This study was conducted to investigate for its effects on reproductive and developmental toxicity of recombinant human epidermal growth factor (rhEGF) in Sprague-Dawley rats. Male rats were administered rhEGF at doses of 1, 10, 100, and 1000$\mu$g/kg/day, respective1y, by subcutaneous injection from 63 days before and throughout to mating period until the day before sacrifice. Female rats were administered rhEGF at the same doses from 14 days before mating to day 20 of gestation or to day 21 of lactation. We examined the male and female fertility indices and maternal toxicity of F0 parental animals. Also, we examined the external, visceral, or skeletal malformation of fetuses, growth and development, behavior, and/or reproductive performance of F1 animals. At the highest dose (1,000 $\mu$g/kg), the mean body weights of F0 animals were significantly increased in males and females at 3 or 2 weeks after treatment, respective1y. No clinical signs and food intakes were observed at any time during the experimental period by rhEGF treatment. In autopsy examination, the relative and absolute liver weights significantly increased in both sexes of 1,000 $\mu$g/kg. At the highest dose (1,000 $\mu$g/kg), there was a statistically significant increase of pregnancy period and the number of dead fetuses. Moreover, significant increase of mean fetal body weight and decrease of number of live fetuses, which related to the difficult dilivery were observed in highest dose group. In Fl examination, no adverse effects on external, visceral, and skeletal malformation, physical and functional development, behavior or reproductive ability of Fl animals were observed in any group. Also, there was no significant difference between control and treated groups in copulation or fertility indices of Fl animals. These results indicate that rhEGF had no adverse effect on fertility and reproductive ability of Sprague-Dawley rats.

• 한국수산과학회지
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• 제36권6호
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• pp.646-653
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• 2003

Investigations were made on the population structure, sex ratio, growth, and recruitment patterns of Leptochela sydniensis in the southwestern coastal areas of Korea, between May 2000 and December 2001. Spawning period, fecundity, brood loss, reproductive output, and size at sexual maturity also were examined. The results of the sex ratio showed that females were more numerous than males during the overall study period. Parameters of growth were estimated using the modified von Bertalanffy growth function (VBGF) model incorporating seasonal variation into growth. Females grew somewhat faster and reached a larger size than males $(L\infty=12.80\;mm\;CL\;and\;K=0.70\;yr^{-1}\;or\;females,\and\;L\infty=12.08\;mm\;CL\;and\;K=0.69\;yr^{-1}$ for males). The structure of recruitment patterns obtained by the FiSAT program indicated one normally distributed group. Based on the occurrence of ovigerous females and the gonadosomatic index (GSI), the main spawning season was from June to August. Analysis of covariance indicated that brood loss was not observed during the incubation period. The size at which $50\%$ of females are mature is estimated as 5.48 mm CL.

• 한국작물학회지
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• 제45권2호
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• pp.97-102
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• 2000

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea.

• 한국발생생물학회지:발생과생식
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• 제27권3호
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• pp.101-115
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• 2023

Environmental factors impact oyster growth, condition, and gonadal development, which is linked to gamete characteristics observed through histology. The reproductive cycle of bivalves is related to energy storage and utilization. Therefore, in this study, the year-round growth change and gonadal development of oysters were observed using histological analysis, and the biochemical composition changes were confirmed. The oysters used in this study are being nurtured in Gadeok-do, and 40 oysters were randomly sampled monthly from March 2021 to February 2022. Result of histological analysis of gonads, oysters were showed early development from December to February, late development from March and April, mature and ripe from May to July, spawned from August to October, and spent from November to December. Condition index values of oysters decreased in summer and autumn and increased again when entered the spent after spawning. The protein content of oysters was high in May, the maturity period, and the lipid content decreased during the spawning period. In addition, EPA and DHA, the major fatty acids of oysters, were low during the spawning period and high during the maturation period. As a result, this study suggested a close relationship between changes in oyster growth, biochemical composition, and the reproductive cycle.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.195-195
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• 2017

The water in the crop cultivation shows difference according to the variety of crop, cultivations period and climatic condition. The growth and development, quantity and fruit enlargements are affected by soil water conditions. In previous study, leaf area and photosynthesis are decreased by lower soil moisture. Other research reported that excess moisture condition at vegetative and reproductive growth period in cultivation of soybean caused highest reduction in crop growth rate (CGR) and dry weights of plant parts. In particular, the damage was bigger during vegetative growth stage than reproductive growth period. Soybean (Glycine max (L.) Merill) is useful and popular crop throughout the world. It is very popular crop in Korea, China, Japan and other Asian countries. Soybeans used in various way including soybean sprouts, paste, soymilk, oil and tofu. Two soybean cultivars grown in four different irrigation conditions were determined for physiological responses. In this study, we examined leaf area (LA), leaf dry weight (LDW), specific leaf area (SLA), root dry weight (RDW) and shoot height (SH) in different water conditions. 50mL/9day irrigation periods showed the lowest contents in LA, LDW, RDW, SH. Water deficit caused increase of leaf Water saturation deficits (WSD), Cheongjakong 3 and Taekwangkong showed increase of leaf water saturation deficits (WSD) in drought conditions and leaf water potential and stomatal conductance were decreased. Photochemical efficiency was decreased in 50mL/1day irrigation condition while, there was decrease of growth and development in 50mL/9day with drought.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8673-8678
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• 2015

본 논문은 토마토 생육 진단 시스템 개발에 관한 것이다. 토마토 생육 진단을 위하여 우선 생육에 영향을 미치는 주요 지표를 정의하였고, 이 지표를 이용하여 토마토 생육 상태에 대한 진단과 이에 따른 조치 정보를 제공한다. 생육에 대한 지표는 지속적인 관찰을 통하여 생육 상태를 확인하는 측정 지표(Measure Index; MI)와 현재 토마토가 영영생장 단계인지 또는 생식생장 단계인지를 판단하는 단계 지표(Period Index; PI)로 구성되었다. 본 시스템의 관찰일지는 MI와 PI에 대한 기록 정보를 입력하는 기능을 제공하고 있다. MI인 경우, 진단은 관찰일지에 기록된 데이터와 미리 정의된 해당 지표에 대한 정상 기준(표준) 값을 비교한 결과이다. PI인 경우 미리 정의된 영양 생장 지표와 생식 생장 지표에 체크를 하여 어느 부분에 치우쳤는지 판단하도록 만들어졌다. 진단 결과 정의된 조치를 수행하는 기능을 서비스한다. 본 시스템은 타 작물로 서비스 확장을 고려하여 구현되었다. 본 시스템을 이용하면 농가에게 정확한 생육 진단과 그에 따른 조치 정보를 제공할 수 있기 때문에 농가의 생산성 향상에 기여할 것을 기대하고 있다.

• 한국작물학회지
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• 제35권4호
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• pp.295-303
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• 1990

우리나라 참깨 생산성의 저조원인의 하나는 파종기와 생육중의 한발을 들 수 있다. 그러므로 본 연구는 참깨 재배시 한발조건에 따른 생리적 반응이나 주요 형질들이 민감하게 반응하는 시기를 구명한 결과는 다음과 같다. 1. 한발에 의한 참깨의 고사주는 영양생장기는 한발처리 40일 이후부터 생식생장기는 20일 이후부터 나타났다. 2. 영양생장기보다 생식생장의 한발이 피해가 더 컸다. 3. 모든 유용형질들은 영양생장기는 40일 한발까지, 생식생장기는 30일 한발까지 회복이 가능하였으나 그 이후는 거의 불가능하였다. 4. 한발로 인한 참깨의 수량은 한발일수가 연장됨에 따라 감수폭이 컸으며 영양생장기에는 29-80%, 생식생장기에는 49-85%의 감수폭을 보였다. 5. 한발조건에서 등숙율을 제외한 모든 유용형질들은 수량과 고도의 정의 상관관계를 나타내었다. 6. 한발로 인한 유분함량은 한발일수가 경과함에 따라 52%에서 42%까지 감수하였으며, 영양생장기 보다 생식생장기에서 더욱 감소하는 경향을 보였지만 지방산조성과는 무관하였다. 7. 이상의 결과 참깨는 한발로 인해 stress를 받으면 생육전반에 걸쳐 계속적인 영향을 받아 유용형질들의 완전회복이 불가능하여 수량감소를 가져온다는 사실이 인정되었다.

• 생물환경조절학회지
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• 제18권2호
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• pp.142-147
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• 2009

단기간 침수처리에 의한 유채의 영양생장과 생식생장기의 생리적 반응, 지방산 조성과 수확량에 관하여 조사하였다. 영양생장 단계에서 10일과 생식생장 단계에서 4일 침수한 결과를 영양생장과 생식생 장기 모두 광합성, 기공전도도와 증산량은 침수처리 기간과 회복시기에 현저하게 감소하였다. 침수처리가 끝난 처리구에서 광합성과 기공전도도는 $2{\sim}3$일 내에 대조구와 비슷한 경향을 보였다. 침수처리된 작품의 지방산 조성은 대조구에 비해 통계적 유의성의 차이를 보이지 않았지만 수확량과 관련된 요인들에서 현저하게 감소함으로 생식생장 단계에서의 단기간 침수처리가 수확량 요인에 큰 영향을 줌으로서 종자 수확량에 영향을 미칠 것으로 사료된다.