• Development and Reproduction
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• v.25 no.4
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• pp.299-303
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• 2021

The ascidian Halocynthia aurantium (sea peach), a marine invertebrate, belongs to the same genus of the phylum Chordata along with the ascidian Halocynthia roretzi (sea pineapple), which is one of the model animals in the field of developmental biology. The characteristics of development and reproduction of H. aurantium are not yet known in detail. In order to find out the spawning period of H. aurantium, we investigated development of the gonads during the annual reproductive cycle. Testis and ovary were both in the bisexual gonads (ovotestes) of H. aurantium, which is a hermaphrodite like H. roretzi. In H. aurantium, the right gonad was longer and slightly larger than the left gonad throughout the year. In each gonad, the number of the testis gonoducts was slightly higher than that of the ovary gonoducts. These features were similarly observed in H. roretzi. However, the number of the testis gonoducts and the ovary gonoducts in each gonad of H. aurantium was about half that of H. roretzi. The gonads of H. aurantium contracted during the winter and summer seasons. The gonads decreased to the smallest size around February, and then started to increase again in March. The gonads were most developed in September of the year. Therefore, it is estimated that the spawning of H. aurantium begins around this period.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.142-147
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• 2009

The effects of short-term waterlogging on physiological responses, fatty acid compositions and yield components of rapeseed at both the vegetative growth and the reproductive growth stages were assessed in this study. Waterlogged plants were treated for a period of 10 days at the vegetative growth stage and 4 days at the reproductive growth stage. The results show that photosynthesis and stomatal conductance at both the vegetative growth and the reproductive growth stage were significantly reduced during the waterlogging period and after the recovery period. When the plants were removed from water, photosynthesis and stomatal conductance progressively restored similar values to those of control plants within $2{\sim}3$ days. Fatty acid compositions were unaffected by waterlogging treatment. However, yield components (pod number and pod length) of the waterlogged treated plants at the reproductive growth stage were significantly reduced. These results suggest that short-term waterlogging may thus influence oilseed yield component.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8673-8678
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• 2015

This study is on the development of the growth diagnosis system for tomato. We defined the key index which affect to the growth of the tomato. Using the key index, we can make a diagnosis the status of the growth and take action to tomato. The index consists of Measure Index(MI) which is used to confirm the status of the tomato using the continuous growth check and Period Index(PI) which decide to the step whether vegetation period or reproductive growth period of the tomato. The system supports MI and PI recording module using the observation diary. In case of MI, the diagnosis is the result of the comparing work with the observed data and the standard value of MI. A a result of diagnosis, the system provides the action information. The system implemented to extend to the other plants. Using the system, Farms may be expected to enhance the productivity.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.1-10
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• 2008

Spermatogenesis and the reproductive cycle in male Spisula sachalinensis were investigated by cytological and histological observations. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves in that it contains a short midpiece with four mitochondria surrounding the centrioles. But spermatozoon of this species has not axial rod and satellite body in the midpiece. The morphologies of the sperm nucleus type and the acrosome shape of this species have a globe-shape type and modified cap-like shape, respectively. The spermatozoon is approximately $40-45{\mu}m$ in length including the sperm nucleus length (about $1.35{\mu}m$), acrosome length (about $1.50{\mu}m$) and tail flagellum. The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9+2 structure. The spawning period of these species lasts from June to July, and the main spawning occurs in July when seawater temperatures are greater than $20^{\circ}C$. The male reproductive cycle of this species can be categorized into five successive stages: early active stage (October to January), late active stage (February to April), ripe stage (April to June), partially spawned stage (June and July), and spent/inactive stage (August to September).

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.142-148
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• 1999

Monthly changes in the gonad index (GI), egg-diameter composition, gonadal development, reproductive cycle of the ark shell, Scapharca subcrenata, were investigated by histological method and morphometric data. This species is dioecious and oviparous. The gonad is located among the subregion of mid-intestinal gland, digestive diverticula and the outer fibromuscular layers compacted by the fibrous connective tissues and muscle fibers. The gonad index sharply increased in May, reached the maximum value in June, and then gradually decreased from July to December. The reproductive cycle of this species can be divided into six successive stages: early active stage (January to May), late active stage (June to July), ripe stage (June to August), partially spawned stage (July to September), degenerative stage (August to December), and resting stage (January to April). S. subcrenata spawns once a year between July and early September, and the main spawning occurred between July and August when the water temperatures were above $20^{\circ}C$. This evidence suggest that timings of maturation and spawning are closely related to water temperatures. Even though the spawning period was once a year, it is assumed that the number of spawning frequencies (broods) may occur more than twice during the spawning season.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.147-151
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• 1998

The reproductive phenology of Gracilaria verrucosa was studied in Cheongsapo near Pusan, Korea. Among the life history phases, tetrasporic plants occurred dominantly in varying degrees of abundance throughout the year except from July to September. Cystocarpic plants increased rapidly during summer, and then recorded maximum abundance in July. Whereas, seasonal peaks of spermatangial plants were observed in April and September. However, they were less than cystocarpic plants in abundance. Vegetative plants dominated from December to May for long period, with a occurrence peak in February. Even though fertile plants in both gametophytes and tetrasporophytes occurred throughout the year, their seasonal abundance suggests that the positive correlation between reproduction and water temperature is basically found in the reproductive pattern of Gracilaria verrucosa. The distributional aspect of life history phases appears to be related with differences of their longevity, fecundity or survivorship.

• Animal cells and systems
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• v.8 no.1
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• pp.33-40
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• 2004

Reproductive cycle and spawning rhythm with lunar cycle of the ascidian, Halocynthia hilgendorfi ritteri were investigated by histological examination. The specimens were sampled in the coastal waters of Yongdam, northwest of Jeju Island, Korea, from November 2001 to January 2003. H. hilgendorfi ritteri is a synchronous hermaphrodite; the gonads are located in the mantle. The reproductive cycle can be grouped into the following successive stages in the ovary: growth (February to June), vitellogenesis (April to September), mature (July to December), spent (November to February), and recovery (December to April). Likewise, in the testis, the stages observed were: growth (October), mature (October to December), spent (November to February), and resting (January to September). Major spawning probably occurs between November and January, when water temperatures decrease. The histological observations of the gonads suggested that this species is a multiple spawner during the spawning period. Spawning occurred between the new moon and full moon, and again between the full moon and new moon, suggesting that the spawning rhythm is influenced by the lunar cycle.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.331-334
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• 2003

The assessment of reproductive potentials of female gayal under semi-intensive management was conducted with 18 animals in Bandarban hilly area of Bangladesh. Age at first estrous (days), age at first conception (days), length of estrous cycle (days), number of service per conception (natural), gestation period (days), age at first calving (days), and calving interval (natural service) (days) of gayal were $598.2{\pm}168.44$, $723{\pm}169.94$, $21.86{\pm}2.93$, 1.41, $296.05{\pm}3.87$, $1014.42{\pm}260.32$ and $465{\pm}80.48$ respectively. Daily milk yield and lactation length of gayal were $304.98{\pm}30.46ml/day$ and $116.67{\pm}8.08days$. Gayal male calves had higher birth weight (19.67 kg) than female calves (15.58 kg) in first lactation. Birth weight increases in second and third lactation than first lactation in both male and female calves. Highest conception rate observed in winter season and 70.60% successful conception occur when service was given within 21-30 h of estrous. Maximum number of female gayal use to come in estrous in winter and calved in monsoon and autumn. Cervicitis and irregular heat were the most reproductive problems followed by metritis, case of abortion, anestrous and repeat breeding. From this study it was observed that the reproductive performance of gayal is very close with the domestic cattle. It may use as beef cattle for the hilly regions of Bangladesh.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.66-70
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• 1986

The findings of a study on reproductive disorders and their causes with 685 dairty cows raised on dairy farms located in Cheju city, Jochun, Hallim and Sung-up are summarized as follows; 1. Among a total 685 dairy cows, 149 heads were identified as having reproductive disorders. They were subdivided into 26 genital organ diseases (3.8%), 53 delivery abnormalities (7.7%), 17 stagnation of after-birth (2.5%), 23 long period nonestrus (3.4%) and 30 repeat breeders (4.4%). Also, the regional incidence of those disorders was recorded as high as 30.8-31.5% in Jochun and Cheju city, and as low as 12.6-16.6% in Sung-up and Hallim districts. 2. The regional incidence of delivery abnormalities was estimated as high as 10.7% in the Cheju city area, and gradually reduced to 8.8% in Jochun, 6.8% in Sung-up and 6.2% in the Hallim district. Abortion (3.1%), stillbirth (2.0%) and 욘새챰 (2.6%) were included in the delivery abnormalities.

• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.207-213
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• 2012

The trunk conformations of the Gyeongju Donggyeongi (GD), Korean native dog was measured in the present study. Also, the information of reproductive activity was investigated in GD dogs. A total of 73 dogs were randomly selected out of 121 dogs in the Gyeongju County in July 2010, which were registered by inserting electronic chips in the withers. The hair colors of the GD were white, yellow, black and tiger brindle, the mean withers heights were $45.46{\pm}4.17cm$ and $49.28{\pm}3.56cm$ for female and male dogs, respectively The mean body length to withers height ratios were 117.63% and 116.4% for the female and male dogs. Concerning the reproductive capability of the GD, the mean litter number was $4.6{\pm}1.7$, the optimal mating time was $12.5{\pm}2.3$ days after the rutting season and the mean gestation period was $60.2{\pm}2.8$ days. The results of this study would be useful for compiling the official standard for the adult GD.