Proton Budget for a Japanese Cedar Forest Ecosystem

The proton budget for a Japanese cedar (Cryptomeria japonica) forest in Gunma Prefecture, Japan, was studied by estimating biogeochemical fluxes. The proton budgets were estimated for three individual compartments of the ecosystem: vegetation canopy, and the upper (O horizon + 0–10 cm) and lower (10–100 cm) soil layers. The dominant proton sources in the compartments were atmospheric deposition (1.2 kmol ha^?1 yr^?1), nitrification (5.1 kmol, ha^?1 yr^?1) and base-cation uptake by vegetation (8.0 kmol, ha^?1 yr^?1) respectively. These proton sources were neutralized almost completely within the individual compartments mainly by base-cation release from the canopy or the soil. The sum of internal proton sources was five times as large as that of external ones. Nitrogen input from the atmosphere was 2.2 kmol ha^?1 yr^?1, whereas its output from the lower soil layer was 3.9 kmol ha^?1 yr^?1, indicating that a net loss of nitrogen occurred in the ecosystem. However, this did not cause the acidification of soil leachates because of a sufficient release rate of base cations from the soil.     

Improved fertilization rates by using a large volume tank in red spotted grouper (Epinephelus akaara)

Two types of spawning experiments were carried out using a small or a large tank in order to determine the reason for the low fertilization rate in artificially reared red spotted grouper. The mean fertilization rate in the large tank (45%) was significantly higher than the one in the small tank (22%). The fertilization rates were high when a pair spawned underwater (84%) compared with the `jump-type' spawning behavior (31%). Spawning in the large deep tank was effective for improving the fertilization rate in this species.     

Pine heartwood formation as a maturation phenomenon

The inverse of the relative increment rate of size is proposed as a measure of the maturity of a forest tree. The heartwood content within bole cross sections is modeled semiempirically using asymptotic fitting. It is shown that the present proposal for a definition of maturity statistically explains heartwood content far better than age or size. The heartwood content appears to be independent on growth rate and tree size.     

Genetic engineering of maize (Zea mays) for high-level tolerance to treatment with the herbicide dicamba

Herbicide-tolerant crops have been widely and rapidly adopted by farmers in several countries due to enhanced weed control, lower labor and production costs, increased environmental benefits, and gains in profitability. Soon to be introduced transgenic soybean and cotton varieties tolerant to treatments with the herbicide dicamba offer prospects for excellent broadleaf weed control in these broadleaf crops. Because monocots such as maize (Zea mays) can be treated with dicamba only during a limited window of crop development and because crop injury is sometimes observed when conditions are unfavorable, transgenic maize plants have been produced and tested for higher levels of tolerance to treatment with dicamba. Maize plants expressing the gene encoding dicamba monooxygenase (DMO) linked with an upstream chloroplast transit peptide (CTP) display greatly enhanced tolerance to dicamba applied either pre-emergence or postemergence. Comparisons of DMO coupled to CTPs derived from the Rubisco small subunit from either Arabidopsis thaliana or Z. mays showed that both allowed production of transgenic maize plants tolerant to treatment with levels of dicamba (i.e., 27 kg/ha) greatly exceeding the highest recommended rate of 0.56 kg/ha.     

Environmental DNA analysis reveals the spatial distribution,abundance, and biomass of Japanese eels at the river‐basin scale

相似文献   

A simple and rapid method for the analysis of fish histamine by paper electrophoresis

ABSTRACT:   The described analytical method for histamine determination in fish and seafood consists of sample extraction, adsorption onto a paper disc, application of the paper disc onto electrophoresis paper, electrophoresis for only 10 min, drying, and color developing by Pauly's reagent. Histamine can be satisfactorily detected and completely separated from histidine, carnosine and other Pauly reagent-positive compounds. This method does not require expensive instrumentation and any tedious pretreatment to eliminate potential interference by other imidazole compounds, such as histidine or carnosine. This method can be used to detect histamine in multiple fish and seafood samples simultaneously that contain as little as 15 p.p.m. histamine (1.5 mg/100 g).     

Effects of temperature on vitellogenesis in Japanese eel Anguilla japonica

ABSTRACT:   Cultured immature female Japanese eels acclimated to sea water at either 10 or 20°C were treated weekly with salmon gonadotropin fraction (sGTH) in order to investigate the effects of water temperature on artificial induction of ovarian maturation. In eels maintained at 20°C, ovulation was induced in 11 of 18 fish during the experimental period of 13 weeks, whereas at 10°C all fish showed a low gonadosomatic index (GSI) at the end of the experiment. Plasma vitellogenin levels were higher in eels kept at 20°C than in eels at 10°C throughout the experiment. However, no significant differences were observed in the plasma testosterone and estradiol-17β levels between groups. Eels pretreated with sGTHs at 10°C for 13 weeks were separated to two different temperature (10 and 20°C) groups, and received the same weekly sGTH injections. In eels transferred to 20°C, plasma vitellogenin levels, GSI and oocyte diameter were increased, but these values were maintained at low levels in eels that remained at 10°C. These results clearly indicate that water temperature is an important factor regulating vitellogenesis in the Japanese eel.     

Relationships between quality parameters and content of glycerol galactoside and porphyra-334 in dried laver nori <Emphasis Type="Italic">Porphyra yezoensis</Emphasis>

ABSTRACT:   Glycerol galactoside (GG; floridoside + isofloridoside) and porphyra-334 (P-334) are contained in nori (Susabinori Porphyra yezoensis and Asakusanori Porphyra tenera ). Glycerol galactoside has been found to have bifidogenic growth stimulator activity and P-334 is known to have ultraviolet-absorbing activity in the UVA region of sunlight. These substances have, respectively, potential for application to pre-biotic foods and in cosmetics as a sunscreen. In the present study, to investigate the relationships between GG and P-334 contents and the quality of nori, we measured the GG and P-334 contents with other components (total protein, chlorophyll-a, β-carotene and phycobillins) that are related to the quality of nori samples produced from different production areas and with different qualities. We found that the GG content was closely negatively correlated with the contents of other components, whereas P-334 was positively correlated with the other components. From these results, it is suggested that low-quality nori is a potential source of GG, and as a source for P-334, scraps of nori produced during nori processing should be suitable.     

Population structure and stock identification of chum salmon Oncorhynchus keta from Japan determined by microsatellite DNA variation

Variation at 14 microsatellite loci was surveyed in 26 chum salmon Oncorhynchus keta populations from Japan, one population from West Kamchatka and three populations from North America to determine population structure. Microsatellites were then applied to estimate stock composition of chum salmon in mixed-stock fisheries. The genetic differentiation index (F _st) over all populations and loci was 0.031, with individual locus values ranging from 0.010 to 0.081. Seven regional populations were observed in Japanese chum salmon, with late-run populations from the Pacific Coast of Honshu the most distinct. Japanese populations displayed greater genetic diversity than did those in North America. Transplantation history in some Japanese river populations influenced their present genetic characteristics. Analysis of simulated mixtures from fishery sampling suggested that accurate and precise regional estimates of stock composition should be produced when the microsatellites were used to estimate stock compositions. Stock compositions for a 2005 sample of maturing, migrating chum salmon off the north-west coast of Hokkaido near the border of the Sea of Japan and the Sea of Okhotsk indicated that this region may be a migration corridor for Hokkaido populations from the Sea of Japan coast. Microsatellites have the ability to provide fine-scale resolution of stock composition in Japanese coastal fisheries.