• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.56-61
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• 1999

Oxygen consumption rate of Far eastern catfish, Silurus asotus, weighing 280g, was measured using continuous flow respirometry chamber linked computer monitoring system. Mean oxygen consumption rates at $15^{\circ}C,\;20^{\circ}C,\;25^{\circ}C$, and $30^{\circ}C$ were ranged in 35.2$\~96.4mg\;O_2/kg$ fish/hr, 78.6$\~127.9mg\;O_2/kg$ fish/hr, 120.1$\~231.7mg\;O_2/kg$ fish/hr, and 197.5$\~352.3mg\;O_2/kg$ fish/hr, respectively. The oxygen consumption rates increased with increasing water temperature (p<0.05). A photoperiod-mediated oxygen consumption rates was higher during the light period than during the darkness (P<0.05). When acclimated with different photoperiods, 24L:0D, 12L:12D, and 0L:24D, the lowest oxygen consumption rate was observed in the continuous darkness (0L:24D). The differences between maximum and minimum oxygen consumption rates oyer 24 hour increased with increasing water temperature and the difference was the highest in 12L:12D. Oxygen consumption rate changed suddenly at dawn and at dusk.

• Journal of Life Science
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• v.16 no.4
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• pp.618-625
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• 2006

Patterns of induced daily torpor were measured in the striped field mouse, Apodemus agrarius, in response to low temperature, food deprivation and various photoperiods using implanted data loggers. A total of 8 of 21 females entered daily torpor in response to low outside ambient temperature (Ta) during winter and spring, constant low Ta $(4^{\circ}C)$ or food deprivation $(23^{\circ}C)$ during summer, but 2 of 23 males did only in response to low outside Ta during winter. This fact indicates that torpor is an adaptive hypothermia to unpredictable environment in both some males and females, as well as that torpor was inhibited in males in the reproductive season as in other mammals, which is regarded as a strategy not to reduce the chance of copulation. As for females, however, torpor was employed in response to unpredictable environment even in the reproductive season, suggesting that alternative strategies other than keeping the chance of copulation maybe hired by females to keep the population. Torpor bout generally began at $6{\sim}12$ AM, but the decrease of body temperature $(T_b)$ began mainly at $4{\sim}6$ AM at any conditions, the time when Ta is lowest. This strategy might be also adopted for reducing heat loss to unpredictable environment. Minimum $T_b$ of both males and females during torpor did not fall below $16.5^{\circ}C$. Photoperiod had no influence on the incidence and timing of daily torpor in either males and females. The similar timing of torpor bout in response to the 3 different photoperiods (24D, 16L:8D or 8L:16D) under the constant temperatures $(4^{\circ}C\;or\;23{\pm}2^{\circ}C)$ suggests that entering time of torpor might be controlled by the circadian rhythm of the mice rather than by the photoperiod.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.352-357
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• 2004

This study was carried out to investigate the effects of temperature and photoperiod on the growth of Fagopyrum tataricum. It showed a tendency to promote the germination rate and plant height of tartary buckwheat under high temperature. Plant height and number of leaves were promoted in the order of 25 ＆gt; 20 ＆gt; 15 ＆gt; 3$0^{\circ}C$ under the different temperature after 30 days of the planting. In the 10, 12, 14hr photoperiods at 2$0^{\circ}C$, plant height, number of leaves and dry weight were increased as much as photoperiod became long except by 16hr. Rutin contents was not regular both common and tartary buckwheat under the photoperiods. The rutin content in leaves was higher than stem. Compared to yield of tartary and common buckwheat, plant height, number of leaves, number of branch and stem diameter of tartary buckwheat increased more than common buckwheat. Especially, number of leaves was increased about 2.5 times more than common buckwheat. And there was a difference in about 2.1 times in grain weight and about 5.4 times in number of grains. Rutin content was 1469.8mg/l00g in grain of tartary buckwheat. It was about 60 times higher than 22mg/100g in grain of common buckwheat.

• Journal of Practical Agriculture & Fisheries Research
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• v.6 no.1
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• pp.41-49
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• 2004

This study was carried out to investigate the effects of temperature and photoperiod on the growth of Fagopyrum tataricum. It showed a tendency to promote the germination rate and plant height of tatary buckwheat under high temperature. Plant height and number of leaves were promoted in the order of 25>20>15>30℃ under the different temperature after 30 days of the planting. In the 10, 12, 14hr photoperiods at 20℃, plant height, number of leaves and dry weight were increased as much as photoperiod became long except by 16hr. Rutin contents was not regular both common and tatary buckwheat under the photoperiods. The rutin content in leaves was higher than stem. Compared to yield of tatary and common buckwheat, plant height, number of leaves, number of branch and stem diameter of tatary buckwheat increased more than common buckwheat. Especially, number of leaves was increased about 2.5 times more than common buckwheat. And there was a difference in about 2.1 times in grain weight and about 5.4 times in number of grains. Rutin content of plant parts was higher in the order of leaf>stem>grain in common buckwheat at the harvest. But it was higher with order of leaf>grain>stem in tatary buckwheat. Rutin content was 1469.8mg/100g in grain of tatary buckwheat. It was about 60 times higher than 22mg/100g in grain of common buckwheat.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.1
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• pp.31-37
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• 2012

Many mammals in temperate zones are affected by the distinctive changes of the four seasons in these zones. Their reproductive status is active in the summer climate and inactive during severe winter weather. The golden hamster (Mesocricetus auratus) is seasonal breeding animal whose sexual activities are regulated by photoperoidism. The reproduction and metabolism are activated by long summer days (LD) and inhibited by short winter days (SD). After several months of SD, animals become refractory to this inhibitory photoperiod and spontaneously revert to LD-like physiology. The suprachiasmatic nuclei (SCN) house the primary circadian oscillator in mammals. Seasonal changes in the photic input to this structure control many annual physiological rhythms via SCN-regulated pineal melatonin secretion, which provides an internal endocrine signal representing photoperiod. The aim of this study was to assess the variation in the morphology of the testis in relation to the natural photoperiod in male golden hamsters. The hamsters were castrated at different weeks (2, 5, 8, and 15). The cell numbers of tubules with spermatogonia (SG), spermatocyte (SC), spermatids (ST), and spermatozoa (SZ) were recorded in each sample. The results showed that testicular regression of golden hamsters occurred in the SD-treated animals. The present investigation determines that the effects of the photoperiod on the reproduction of male golden hamsters. It was also found that the circadian period increases the rate of reproductive inhibition in animals exposed to inhibitory photoperiods.

• Development and Reproduction
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• v.18 no.3
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• pp.133-137
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• 2014

Rearing experiments were conducted using several regimes combined with different photoperiods and water temperatures to investigate the role of temperature and photoperiod as environmental cues regulating reproduction in red marbled rockfish, Sebastiscus tertius. The initial gonadosomatic index (GSI) was $1.62{\pm}0.32%$ and that in the $15^{\circ}C$ control was $7.01{\pm}0.46%$ at the end of the experiment. The highest GSI was $9.10{\pm}0.35%$ in the 12L:12D photoperiod-treated fish. The highest GSI at $19^{\circ}C$ was $15.03{\pm}0.86%$ in the 12L:12D photoperiod treatment. The initial hepatosomatic index (HSI) was $3.09{\pm}0.72%$ and that in the $15^{\circ}C$ control was $3.88{\pm}0.45%$. The highest HSI was $4.00{\pm}0.56%$ in the 15L:9D treated fish. The highest HSI at $19^{\circ}C$ was $4.05{\pm}0.63%$ in the 12L:12D treated fish.

• Development and Reproduction
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• v.21 no.2
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• pp.223-228
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• 2017

This study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analysis of gonad tissue showed that the gonad of 10L:14D and 12L: 12D treatment groups were resting phase with spermatogonia and perinucleolus stage oocytes but the gonad of 14L:10D treatment group was still ripe phase with spermatozoa and mature stage oocyte. The $FSH{\beta}$ and $LH{\beta}$ mRNA expression in pituitary drastically decreased shot photoperiod treatment from July (spawning period). These results suggest that photoperiod is considered to be the most effective environmental factor in controlling the reproductive cycle of damselfish.

• Development and Reproduction
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• v.21 no.2
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• pp.215-221
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• 2017

Bitter melon (Momordica charantia, MC) has been used in traditional Korean medicine in treating diabetes. In addition, some reports were emerged, showing the antifertility activities of MC in mammals. We investigated the effects of ethanolic MC extract on the reproductive activity of golden hamsters whose spermatogenetic capacity is controlled by their photoperiods. The animals were divided into 4 groups: long photoperiod (LP) control, short photoperiod (SP) control, and LP animals treated with MC. The animals were orally ingested with low (0.03 g/kg) or high (0.15 g/kg) concentrations of the ethanolic extracts for 8 weeks on the daily basis. The control animals received the vehicle. The animals were then mated with age-matched females, experienced pregnancy. As results, the LP control animals showed active large testes but SP control animals displayed remarkably reduced testes. The animals treated with both concentrations of MC extracts demonstrated large testes, indicating fertile activity as animals in LP. LP control animals had litters as expected, but SP controls had no litters at all. MC extract showed the same results as LP animals in generating offsprings. These results suggest that the MC extract does not change the photoperiodic influence on reproductive activity of male golden hamsters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.281-288
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• 2007

Photoperiod sensitive genetic male sterile (PGMS) rice is sterile mutant controlled by photoperiod. A PGMS mutant 920S was sterile grown under long-day (LD) photoperiod (14 h light/10 h dark) but fertile grown under short-day (SD) photoperiod (10 h light/14 h dark). Proteome analysis revealed that 12 protein spots were differentially expressed in the spikelets of 920S plants either treated with LD or SD photoperiod. Among these proteins, three proteins including chlorophyll a/b binding protein, vacuolar ATPase ${\beta}-subunit,\;{\alpha}-tubulin$ and an unknown protein were more than three-fold abundant in the spikelet of the SD-treated plants than those of the LD-treated plants. On the other hand, eight proteins including acetyl transferase, 2, 3- biphosphoglycerate, aminopeptidase N, pyruvate decarboxylase, 60S acidic ribosomal protein and three unknown protein spots were more abundant in the spikelets of the LD-treated plants than those of the SD-treated plants. The results suggest that the observed proteins may be involved in sterile or fertile pollen development under LD or SD photoperiod respectively in the PGMS mutant rice.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.231-238
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• 2010

The Induction of regeneration and maturation in the free-living gametophytes of Ecklonia stolonifera Okamura was studied at four temperatures (5, 10, 15, and $20^{\circ}C$), four levels of irradiance (5, 10, 20, and 40 ${\mu}mol\;m^{-2}s^{-1}$) and three photoperiods (14:10, 12:12, and 10:14 h L:D). Female gametophyte fragments were maintained in active regeneration without reaching sexual maturity under $5{\sim}10^{\circ}C$, 10 ${\mu}mol\;m^{-2}s^{-1}$, 10:14 h (L:D), whereas the conditions for male gametophytes were slightly different at $20^{\circ}C$, 40 ${\mu}mol\;m^{-2}s^{-1}$, 10:14 h (L:D). The sexual maturation of female and male gametophytes was facilitated at $15^{\circ}C$, 20 ${\mu}mol\;m^{-2}s^{-1}$, 14:10 h (L:D). These results provide basic information for controlling the regeneration and maturation of the free-living gametophytes for artificial seed production of E. stolonifera.