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1.
Stephen Adu-Bredu Taketo Yokota Kazuharu Ogawa Akio Hagihara 《Journal of Forest Research》1997,2(1):31-37
The study was carried out in a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.), stand over a span of three years from July 1992 to June 1995, primarily to predict litter production
from exteral tree dimensions by combining open-top clothtrap and clipping methods. Litter production was virtually concentrated
in October and November. Stem cross-sectional area at the crown base was proved to be the reliable predictor of litter production,
and that single regression model was evolved irrespective of year. The regression model had proportional constants of 2.696
× 10−2 and 3.540 × 10−2 kg cm−2 year−1 for leaf litter and total litter production, respectively. Utilizing the model, leaf litter production of the stand was assessed
to be 5.04, 5.12, and 4.99, and total litter production to be 6.48, 6.58, and 6.40 Mg ha−1 year−1 for the first, second and third year, respectively. Biomass increment was 6.67, 7.80, and 7.70, tree mortality was 0.15,
0.13, and 0.41, and insect grazing was 0.09, 0.05, and 0.002 Mg ha−1 year−1 for the first, second and third year, respectively. Above-groud net production was therefore 13.39, 14.55, and 14.51, Mg
ha−1 year−1, and biomass accumulation ratio (biomass/net production) was 1.86, 2.21, and 2.76 year for the first, second and third year,
respectively. Considering data from earlier studies and the results of this study, biomass accumulation ratio,BAR (year), of hinoki stands was best related to above-ground biomass,y (Mg ha−1), using the power function:BAR=0.112y
0.936. Excluding seedling stands, leaf efficiency (above-ground net production per unit leaf mass) of hinoki stands was 0.91±0.02
(SE) Mg Mg−1 year−1, irrespective of stand biomass or age. 相似文献
2.
Koji Murashita Hirofumi Furuita Hiroyuki Matsunari Takeshi Yamamoto Masahiko Awaji Kazuharu Nomura Jiro Nagao Hideki Tanaka 《Fish physiology and biochemistry》2013,39(4):895-905
The pancreatic digestive enzymes, trypsin, chymotrypsin, lipase and amylase were partially characterized, and changes in their activities were examined during the initial ontogeny of Japanese eel Anguilla japonica larvae from 5 to 34 days post-hatching (dph). The pH optima of the eel larval enzymes were narrower than those other fish species; trypsin activity was highest at pH 9, chymotrypsin and amylase activities were highest at pH 7 and 8, and lipase activity was highest at pH 8 and 9. In an analysis of thermal profiles, the larval pancreatic enzymes had a high optimal temperature and high thermal stability, which are typical of fish from the tropics. At 12 and 13 dph, lipase activity and gene expression levels of trypsin (-a and -b), lipase and amylase decreased markedly, suggesting a marked change in larval metabolism at that time. These data could be useful in the development of artificial larval diets in Japanese eel. 相似文献
3.
Hirofumi Furuita Tatsuya Unuma Kazuharu Nomura Hideki Tanaka Tsuyoshi Sugita & Takeshi Yamamoto 《Aquaculture Research》2009,40(11):1270-1278
This paper describes the relationship between the egg vitamin concentrations and the egg quality in the Japanese eel Anguilla japonica . No notable relation was found between any vitamin and the fertilization rate. Hatching and survival rates of larvae, however, significantly increased with an elevated level of egg vitamin C (VC). In contrast to VC, the relation between vitamins E (VE) and A (VA) concentrations and survival rate showed a clear peak, with a reduced survival rate at both higher and lower vitamin concentrations. The ratio of VE to lipid or highly unsaturated fatty acid (HUFA) in eggs positively correlated with hatching and survival rates of larvae. High-quality (HQ) eggs were determined as eggs that produced larvae having a survival rate higher than 80% at 8 days post hatch, and low-quality (LQ) eggs were determined as eggs that did not hatch. The level of VC of HQ was significantly higher than LQ. The results of this study suggest that HQ eggs, which produce larvae having a high survival rate, must have high levels of VC and VE/HUFA ratio and contain optimum levels of VA and VE in Japanese eel. 相似文献
4.
5.
The effects of elevated atmospheric CO2 concentrations on the nighttime respiration were examined for two sample branches of a hinoki cypress tree (Chamaecyparis obtusa) growing in the field with an open gas exchange system for a one-year period from July 1994 to June 1995. The branches were
of a similar size and located at a similar position within the crown. One branch was subjected to an elevated CO2 concentration of 800 μmol mol−1 and the other was subjected to ambient air which had a CO2 concentration of about 370 μmol mol−1. Nighttime respiration rate was higher in elevated CO2 level than in ambient CO2 level. The relationship between nighttime respiration and the corresponding nighttime air temperature was fitted by the exponential
function in every month of the year. The segregation of regression lines between the two CO2 treatments increased gradually as the seasons progressed during the treatment period. TheQ
10 values for nighttime respiration were lower in elevated CO2 (1.9 ≤Q
10 ≤ 3.7) than in ambient CO2 (2.4 ≤Q
10 ≤ 4.5) in every month of the year. TheQ
10 was inversely related to the monthly mean nighttime air temperature in both elevated and ambient CO2. The estimated daily nighttime respiration rate under both CO2 treatments had a similar seasonal pattern, which almost synchronized with the temperature change. The respiration ratio of
elevated CO2 to ambient CO2 increased gradually from 1.1 to 1.6 until the end of the experiment. Our results indicate that the CO2 level and the temperature have a strong interactive effect on respiration and suggest that a potential increase in respiration
of branches will occur when ambient CO2 increases. 相似文献
6.
Ishii N Nakahigashi K Baba T Robert M Soga T Kanai A Hirasawa T Naba M Hirai K Hoque A Ho PY Kakazu Y Sugawara K Igarashi S Harada S Masuda T Sugiyama N Togashi T Hasegawa M Takai Y Yugi K Arakawa K Iwata N Toya Y Nakayama Y Nishioka T Shimizu K Mori H Tomita M 《Science (New York, N.Y.)》2007,316(5824):593-597
Analysis of cellular components at multiple levels of biological information can provide valuable functional insights. We performed multiple high-throughput measurements to study the response of Escherichia coli cells to genetic and environmental perturbations. Analysis of metabolic enzyme gene disruptants revealed unexpectedly small changes in messenger RNA and proteins for most disruptants. Overall, metabolite levels were also stable, reflecting the rerouting of fluxes in the metabolic network. In contrast, E. coli actively regulated enzyme levels to maintain a stable metabolic state in response to changes in growth rate. E. coli thus seems to use complementary strategies that result in a metabolic network robust against perturbations. 相似文献
7.
Tadahide Kurokawa Hideyuki Shibahara Koichiro Gen Kazuharu Nomura Hideki Tanaka 《Fisheries Science》2013,79(4):673-680
The present study analyzed the rate of occurrence of deformities at completion of yolk resorption after Japanese eel larvae were exposed to low-salinity (29 psu) or low-water-temperature (20 °C) conditions (after they had been reared under suitable conditions: 34 psu, 25 °C) at various points between 0 and 8 days post-fertilization (dpf) in order to determine the period of sensitivity of the larvae to low-salinity or low-temperature conditions. No significant differences were observed between the rate of deformed larvae obtained in the groups reared under suitable conditions and the corresponding rates in groups that were exposed to low-salinity or low-temperature conditions at 4 dpf or later, but the frequency of normal larvae showed a downward trend in experimental groups that were subjected to low-salinity or low-temperature conditions at 3 dpf or earlier. Occurrence rates of pericardial edema were significantly higher in experimental groups that were exposed to low-salinity or low-temperature conditions at 2 dpf or earlier. Therefore, it was concluded that the rearing conditions for Japanese eel larvae should be maintained at 34 psu salinity and 25 °C until at least 4 dpf in order to reduce the occurrence of larval deformity at completion of yolk resorption. 相似文献
8.
Tadahide Kurokawa Takuma Okamoto Koichiro Gen Susumu Uji Koji Murashita Tatsuya Unuma Kazuharu Nomura Hajime Matsubara Shin‐Kwon Kim Hiromi Ohta Hideki Tanaka 《Journal of the World Aquaculture Society》2008,39(6):726-735
The occurrence of morphological deformities under different rearing water temperatures (18, 20, 22, 24, 26, 28, and 30 C) was examined in Japanese eel larvae. The rates of hatching and survival until yolk resorption at 22–26 C were higher than those at other water temperatures. Fertilized eggs never hatched at 18 and 30 C. The rates of occurrence of abnormal larvae reared at the water temperatures 24–28 C were lower than those at 20 or 22 C. Pericardial edema and lower jaw deformities occurred most frequently at lower temperatures (20 and 22 C). In contrast, the incubation temperature did not significantly affect the relative frequency of some neurocranial deformities and of spinal curvature. These results imply that the optimal temperatures for rearing Japanese eel eggs and embryos are 24–26 C from the viewpoints of survival and deformity. 相似文献
9.
Keisuke Yamano Kazuharu Nomura Hideki Tanaka 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):499-504
Development of the thyroid gland of the Japanese eel (Anguilla japonica) was studied with the use of tank-reared fish. A single thyroid follicle was first found in larvae at 29 days post hatching (dph), total length (TL) 12 mm. Until reaching 25 mm in TL (100 dph), leptocephali had one or two follicles per individual. The inner colloid of the follicles was weakly immuno-positive against the anti-thyroxine (T4) antibody. The number of thyroid follicles and the immunoreactivity later increased as the larvae grew. Thyroid hormones (TH) T4 and triiodothyronine (T3) were not detected in premetamorphic larvae by radioimmunoassays, but became detectable during metamorphosis. The maximum level of T4 was seen in fish at the end of metamorphosis and in just-metamorphosed juveniles, whereas T3 reached the highest level during metamorphosis and declined toward the end of metamorphosis. The results indicated that the thyroid gland first became active during metamorphosis in the development of eel. 相似文献
10.
Shin-Kwon Kim Hiroyuki Matsunari Kazuharu Nomura Hideki Tanaka Masahito Yokoyama Yuko Murata Kenji Ishihara Toshio Takeuchi 《Fisheries Science》2008,74(4):875-881
ABSTRACT: The effects of dietary taurine levels and lipid contents on the conjugated bile acid composition and growth performance of juvenile Japanese flounder Paralichthys olivaceus were investigated. Six types of diet (three different levels of taurine at two different levels of lipid) were fed to juveniles (average body weight, 0.04 g). Fishmeal that was washed with 70% ethanol to remove taurine was used as the sole protein source. Feeding experiments were carried out at 20°C for 6 weeks. At the end of the experiments, fish were weighed and analyzed for free amino acids in the body and the composition of the conjugated bile acids. The body weight and percent weight gain of the juveniles were improved by the dietary taurine supplementation. The taurine contents of the whole body and tissues increased with the increase of the dietary taurine contents. The conjugated bile acids in the gall bladder consisted of taurocholic acid and taurochenodeoxycholic acid, which increased with the increase of the dietary taurine level. Taurocholic acid accounted for more than 95% of the total conjugated bile acids. This indicates that taurine is the sole amino acid to conjugate bile acid in Japanese flounder. 相似文献