• The Korean Journal of Malacology
• /
• v.20 no.1
• /
• pp.35-43
• /
• 2004

To know the effects on temperature and body size on the clearance rate (CR) of a small tidal flat bivalve, Coecella chinensis, laboratory experiments were performed with 20 individuals of different sizes (ranging from 7 to 25 mm) at 3 different temperatures (10, 15, $20^{\circ}C$). The relationship between body size and CR was determined by an allometric equation. The CR of C. chinensis varied greatly ranging from 0.003 to 0.103 L/individual/hr. Both temperature and body size affected significantly on the CR of C. chinensis. The CR at $20^{\circ}C$was 1.5 times higher than that at $15^{\circ}C$ and 2.8 times than $10^{\circ}C$. The temperature coefficient ($Q_10$) between 10 and $15^{\circ}C$ was higher than that between 15 and $20^{\circ}C$, which indicates that C. chinensis changes its CR more rapidly in lower temperature range. As body size increased, the CR increased more than 10-fold at all temperatures. The CR relative to flesh dry weight (FDW) were fitted well to the power function: CR = a ${\times}$ $(FDW)^b$. The exponent value (b) of the fitted equation ranged from 0.64 to 0.70, which are similar to those of other bivalves. The weight-specific CR ($CR_w$) was still affected by body size (p < 0.05). This implies that smaller individuals require more energy per unit biomass for growth, and the energy requirement for growth decreases as body size increases.

• Korean Journal of Environmental Biology
• /
• v.22 no.3
• /
• pp.438-445
• /
• 2004

A radiotracer study was conducted to evaluate the influence of body size and temperature on the uptake rates of Cd, Se and Zn in the California mussel, Mytilus californianus. Uptake rates of Cd, Se and Zn were determined simultaneously with clearance of the mussels with 3 different size classes (0.07, 0.24 and 0.73 g flesh dry weight $individual^{-1})$ and at 4 different temperatures (3, 8, 13 and $21^\circ{C})$. The weight-specific uptake rates of 3 elements significantly decreased with body size, but increased with temperature. Simultaneously measured clearance rates of mussels were closely associated with metal uptake rates. The significant association of clearance rates and metal uptake rates of mussels emphasizes the importance of functional role of water pumping activity in the metal uptake process in filter-feeding organisms.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.5
• /
• pp.560-571
• /
• 1994

A single station representative of the razor clam, Solen (Solen) strictus, on a macrotidal flat, Inchon, Korea was sampled at bimonthly intervals between May 1989 and July 1990 by using a can corer. Estimates of growth rate and annual production of this razor clam have been made using the techniques of cohort growth analysis. Growth rate and production were highest during the first year after spawning and recruitment. The annual production was $2.83g\;DWt/m^2/yr$, mean annual biomass $256.3\;g/w^20$, and a turnover time of 5.00 yea, giving an annual turnover rate (P/B) of $0.20\;yr^{-1}$. The total annual production in wet weight ($33.22g\;WWt/m^2/yr$) appeared to consist of water in live flesh($72.6\%$) and shell($18.9\%$), whereas the dry weight of the soft parts was $8.52\%$, the ash-free dry weight $5.4\%$, and the ash content $3.1\%$ of the total wet weight.

• Food Science and Preservation
• /
• v.11 no.3
• /
• pp.304-312
• /
• 2004

Early harvested Satsuma mandarin (Citrus unshiu) was treated with hot air at 45$^{\circ}C$ for 2, 4, and 6 hours and stored at 5$^{\circ}C$ for 3 weeks and additional one week at 18$^{\circ}C$ (simulated shelf-life) in order to examine the effect of mild heat treatment on the storage quality of the citrus fruits. Quality attributes of the sample fruits evaluated during storage included the respiration rate, internal gas composition, pH, titratable acidity, soluble solids content, flesh weight loss, firmness, peel color, decay ratio, and sensory properties. The initial respiration rates, just after hot air treatment, were significantly higher in the heat-treated fruits compared to the untreated. However, during storage at 5$^{\circ}C$, the respiration rates showed a similar level in all treatments. Internal gas composition exhibited no significant difference between the heat-treated and untreated samples. Hot air treatment also exerted no significant effects on the pH, titratable acidity, soluble solid contents, flesh weight loss, firmness, and peel color of the fruits during the whole storage period. The decay ratio was manifestly lower in the heat-treated fruits than the untreated. For sensory attributes including visual and organoleptic quality, no significant difference was observed among sample fruits. Results suggested that mild heat treatment with hot air at 45$^{\circ}C$ for 4-6 hours could be used as an effective preconditioning method to keep the postharvest quality of Satsuma mandarin by reducing the decay incidence remarkably during storage.

• Journal of Bio-Environment Control
• /
• v.21 no.3
• /
• pp.252-260
• /
• 2012

This study was carried out to compare the storability in MA storage and quality of paprika fruits among 9 cultivars grown in 2011 and 12 cultivars in 2012. 'Mosanto 7044' was the most proper cultivar in red-type paprika has grown in 2011 for MA storage, because it showed relatively higher fruit weight, firmness, soluble solid content, and the lowest ethylene production rate, as well as the second longest shelf life. 'Stayer' was suitable cultivar in yellow-type paprika cultivated in 2011, because it showed higher firmness, soluble solid content and lower ethylene production rate than other cultivars. 'Nagano' was the most proper cultivar in red-type paprika has grown in 2012 for MA storage. Because it showed relatively higher fruit weight, firmness, flesh thickness and the lowest ethylene production rate and decay ratio, although the shelf life of 'Nagano' was the third longest (28 days). 'Freestar' was the excellent cultivar in yellow-type paprika cultivated in 2012, because it showed higher firmness, vitamin C content and lower respiration rate than other cultivars and the longest shelf life of 26 days. The shelf life had a high correlationship with ethylene production rate (r = -0.5504), and soluble solid (r = 0.6112), as comparing with the shelf life and the fruit characteristics of 21 cultivars paprika has grown in 2011 and 2012.

• Food Science and Preservation
• /
• v.14 no.4
• /
• pp.345-350
• /
• 2007

Shelf-life and quality changes of four leaf lettuce cultivars packaged and stored at four different temperatures (0, 8, 16 and $24^{\circ}C$) were evaluated. Leaf lettuces were packaged in non-perforated polypropylene film (thickness 0.05 mm) bags. Weight loss, respiration rate, freshness degree, pigment content, and surface color were determined. At the storage temperature of $0^{\circ}C$, the weight loss, degree of freshness, pigment content, and change of surface color on packaged leaf lettuces showed no significant difference when compared with all other leaf lettuces. Meanwhile, an increase in storage temperature was observed with the quality changes of each flesh leaf lettuce. The leaf lettuces under storage conditions at $24^{\circ}C$ showed a difference in weight loss of the different types of leaf lettuces during a short storage period. However, there was no clear tendency in weight loss in different types of leaf lettuces as compared with each storage temperature. The rate of respiration and the contents of pigments in the four types of leaf lettuces also showed significant difference as the storage temperature increased.

• Korean Journal of Agricultural Science
• /
• v.29 no.1
• /
• pp.1-7
• /
• 2002

Postharvest characteristics of 'Pingguoli' fruit produced between China and Korea were compared to find an ecological difference. There was a difference in fresh weight per fruit, thus, fruit weight produced in Korea was much higher than those in China. However, no significant differences were confirmed in the level of soluble solid content and flesh firmness. The acidity of Korean 'Pingguoli' was higher than Chinese ones. The external appearance of Korean 'Pingguoli' was not attractive due to the rough and rugged surface. Thus, the prospect of 'Pingguoli' cultivation in Korea seems not to be promised. The general trend of respiration and ethylene evolution during storage did not significantly differed but the amount of $CO_2$ and ethylene production was higher in fruits produced in China. There was a strong similarity in respiration and ethylene evolution pattern to typical climacteric fruits. Thus, 'Pingguoli' is considered as a climacteric fruit. Even though the rate of ethylene production of 'Pingguoli' was relatively high, the storability of 'Pingguoli' showed a strong potential. The further studies in postharvest physiology of pear using 'Pingguoli' and in its breeding potentials as a source of long storage life are needed.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.109-116
• /
• 2018

We investigated the effects of honey bee (Apis mellifera L.) colony size on the pollination of greenhouse-cultivated watermelon grown under the forcing cultivation system. The highest pollination activity of bees was observed ($14.3{\pm}5.0$ honey bees/day) when the bee colony size was 10,000 followed by 7,500 and 5,000 honey bees. There was a positive correlation between the bee colony size and pollination activity (R = 0.262) but insignificant difference in fruit set with different honey bee colony sizes (88%-91%). Evaluation of physical properties revealed that the weight and shape of watermelon were also not significantly different among different colony sizes. However, larger the bee colony size, higher the number of seeds were fertilized and rate of seed fertilization (p > 0.05). Number of seeds and content of sugar were negatively correlated (R = -0.714). Fertilized seeds showed a significant increase in mealy flesh, which has a negative effect on fruit quality, compared with that of the unfertilized seeds. Overall, we found that a colony size of 5,000 honey bees was the most effective for the pollination of watermelon grown under forcing cultivation. A comparison of the effects of bee pollination with those of artificial pollination suggested that artificial pollination can be effectively replaced by bee pollination in the forcing cultivation of watermelon, because fruit set, weight, and shape by bee pollination were similar to those achieved by artificial pollination.

• Journal of agricultural medicine and community health
• /
• v.12 no.1
• /
• pp.80-93
• /
• 1987

Mass chemotherapy of Clonorchis sinensis infection in Korea was started in 1982 with 40mg/kg body weight single dose administration scheme of praziquantel. The purpose of this study was to investigate the efficiency of current mass chemotherapy project and compare the epidemiological changes in endemic area of Ckmorchis sinensis. This study was performed at Kimhae-city and Samrangjin-eup of Miryang-gun, Kyongnam province, highly endemic area of C. sinensis located southeastern part of Korea from July to October of 1986. The therapy project of Kimhae area was performed in 1984, whereas that of Samrangjin was done in 1985 by stool examination of the Korea Association for Parasite Eradication(KAPE) and drug administration of local health centre. The results obtained were as follows; 1) As a results of stool examination from 234 specimens obtained in Kimhae area, the infection rate has decreased to 34.2%from 45.6p in 1983, but the infection rate of C. sinensis from 341 specimens obtained in Samrangjin area did not decrease (58.1%in 1986 490%in 1983). 2) The study in Kimhae area showed that the average EPG decreased remarkably from 4,858 to 1,340 and those classified above the category of heavy infection decreased also from 14.0pp to 1.7%. The study in Samrangjin area showed that the average EPG did decrease drastically from 9,597 to 6,498 and those classified above the category of heavy infection did not go down drastically from 25.2% to 14.2%. 3) The study in Kimhae area showed decrease of Cs.$D._{50}$ in comparison to that in 1983, wheareas Cs.$D._{50}$ in Samrangjin area showed no much difference compared to that in 1983. The intensities of endemicity were represented with the regression equation calculated with the cumulative percentages of EPG count. Regression equation was Y=4.49+1.19 log x in Kimhae area and Y=3.66+127 log x in Samrangjin area. 4) The two stage catalytic model was applied and the calculation lead to the equation $Y=5.33(e^{-0.018t}-e^{-0.016t})$ in Kimhae area and $Y=1.25(e^{-0.010t}-e^{-0.018t})$ in Kimhae area and $Y=125(e^{-0.010t}-e^{-0.050t})$ in Samrangjin area 5) The infection rate of cercaria in P.manchouric-us studied in Kimhae area showed 1.25% which is not much different from that in previous years, wheareas the infection rate of metacercaria in P. parva studied in the same area this year showed 2.5-20.2/gm of flesh in comparison to 64/gm of flesh in 1983. 6) Data of C. sinensis infection on the reservoir host in Kimhae area showed 4 out of 18 dogs, 1 out of 18 rats and that in Samrangjin area showed 2 out of 18 dogs respectively. 7) Among the inhabitants who were under mass chemotherapy in Kimhae area, 71out of them, upon stool examination, showed infection rate of 66.2% and those classified above the category of heavy infection, 2.4%. In comparison to infection rate of 33.7% and those classified above the category of heavy infection, which is 1.0%, obtained from those not under mass chemotherapy showed higher infection rate and somewhat equal distribution of intensity of infection. The above statements reflect the fact that individual therapy besides mass chemotherapy was prevalent in that area. 8) On the other side, the studies in Samrangjin area showed infection rate of 68.7% and those above the category of heavy infection, which is 6.1%, in comparison to infection rate of 58.3% and those above the category of heavy infection, which is 16.5%, in those not under mass chemotherapy. the above reflects that although a good deal of inhabit-ants were classified under light or moderate infection category, those above the category of heavy infection, yet, numbered a lot, and individual chemotherapy has not been going on. In conclusion, it was suggested that the number of reinfected inhabitants among those under mass chemotherapy were numerous. Accordingly, the reinforcement of health education should be followed with mass chemotherapy. The facts of high infection rate exemplified by 65% and high number of those above the category of heavy infection in Samrangjin area say that reevaluation of dosage, number of medication and intervals should be necessarily made.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.265-274
• /
• 2014

Physiological characteristics of two Korean golden kiwifruit cultivars, 'Halla Gold' and 'Haehyang', were compared to determine the storage potential of fruit. The soluble solid levels of the fruit were 8.9 and 6.9 oBrix in 'Halla Gold' and 'Haehyang' at harvest, respectively but increased up to 15.4 in 'Halla Gold' and 17.5 oBrix in 'Haehyang' after 2 months of storage. Major sugars were fructose and glucose, and sucrose content was relatively low regardless of cultivar. The edible quality of 'Haehyang' was better than 'Halla Gold' because of higher amount of sugars. Firmness of the fruits gradually decreased as the increase of storage period in 'Halla Gold' in both flesh and core tissue. Th firmness loss of 'Haehyang' fruit was faster in the first 2 months and then became slow. After 75 days of storage, the firmness of 'Haehyang' fruit was only 5.2% at harvest. Core tissue was soften enough to eat at ripe stage. Wall modifying enzyme activities including xylanase, ${\alpha}$-L-arabinofuranosi-dase and ${\beta}$-galactosidase were consistently higher in 'Haehyang' and the activity of pectate lyase was more increased than 'Halla Gold' after 2 months of storage. Respiration rate of 'Haehyang' was higher than 'Halla Gold' and further increased after 2 months of storage. Weight loss was much higher in 'Haehyang' which showed higher rate of the firmness loss. The storage potential of golden kiwifruit was estimated to be about 2 months for 'Haehyang' and 3 months for 'Halla Gold' when determined on the basis of the fruit firmness.