Development of winter wheat with excellent resistance to pre-harvest sprouting and rain damage

Pre-harvest sprouting and high alpha-amylase activity are the most serious problems for the wheat production in Hokkaido, the northern most part of Japan. It has become more frequent for wheats to be exposed to continuous rain for several days in harvest time. In addition, low temperature below 15 ^°C, combined with rainfall, accelerates the damage of pre-harvest sprouting. Therefore, we started a breeding program in 1998 to develop wheat varieties with excellent resistant to sprouting damage in Hokkaido.Selection and evaluation of pre-harvest sprouting of resistant lines were conducted by two tests. One test was artificial rain treatment of intact spikes and the other was a germination test of hand-threshed grains at 10, 15 and 20 ^°C. The spikes of each line and variety were collected at physiological maturity and at one week after the first sampling date. Falling number was also measured.We have succeeded in breeding a deeply dormant breeding line, Kitakei 1802, from 1,923 doubled haploid lines raised by anther culture from the cross between Kitakei 1616 and Nishikazekomugi. Kitakei 1802 hardly sprouted through 10 days” continuous rainfall treatment at low temperature (15 ^°C) and maintained high falling number (> 300 s) in 2002 and 2003.     

Decomposition patterns of leaf litter of seven common canopy species in a subtropical forest： dynamics of mineral nutrients

Dynamical patterns of mineral elements during decomposition processes were investigated for seven common canopy species in a subtropical evergreen broad-leaved forest by means of litterbag technique over 2 years. The species studied are representative for the vegetation in the study area and differed significantly in chemical qualities of their litter. No significant relationships were found between decomposition rate （percentage dry mass remaining and decomposition constant k） and initial element cuncentrations.However, there were significant correlations betweeu the percentage of dry mass remaining and the mineral element concentrations in the remaining litter for most cases. The rank of the element mobility in decomposition process was as follows： Na = K 〉 Mg ≥ Ca 〉 N ≥ Mn ≥ Zn ≥ P 〉 Cu 〉〉 Al 〉〉 Fe. Concentrations of K and Na decreased in all species as decomposition proceeded. Calcium and Mg also decreased in concentrntion but with a temporal increase in the initial phase of decomposition, while the concentrations of other elements （Zn, Cu, AL and Fei increased for all species with exception of Mn which revealed a different pattern in different species. In most species, microelements （Cu, Al, and Fe） significantly increased in absolute amounts at the end of the litterbag incubation, which could be ascribed to a lange extent to the mechanism of abiotic fixation to humic substances rather than biological immobilization.     

Paraoxon-induced release of β-glucuronidase from rat hepatocytes in vitro

A suspension culture of isolated rat hepatocytes was used to reproduce in vitro the paraoxon-induced release of hepatic β-glucuronidase observed in vivo. After a short latent period, exposure of hepatocytes to paraoxon at 10^?7 to 10^?4M resulted in a typical dose-dependent response, with highest release occurring at 10^?4M paraoxon. With 10^?3M paraoxon, however, response was anomalous with a much-decreased enzyme release. As expected from earlier results in vivo, SV₁-oxon exhibited less effect than paraoxon.     

Identification of metabolites in plasma and urine of Uruguayan propolis-treated rats

Propolis is a resinous substance collected by honeybees from various plant sources. It is extensively used in food and beverages to improve health and prevent diseases such as heart disease, diabetes, and cancer. To investigate the absorption and metabolism of the components in propolis, in the present study, we administered ethanol extracts of Uruguayan propolis (poplar type propolis) orally to rats and analyzed their plasma and urine by high-performance liquid chromatography with photodiode array and mass spectrometric detection. After deconjugation of the components by beta-glucuronidase/sulfatase treatment of the specimen, pinobanksin 5-methyl ether, pinobanksin, kaempferol, chrysin, pinocembrin, and galangin were detected in plasma of rats orally administered propolis. These compounds were detected also in urine after beta-glucuronidase/sulfatase treatment. Furthermore, pinobanksin 5-methyl ether, pinobanksin, chrysin, pinocembrin, and galangin were present in the urine also in free form. These results suggest that flavonoids in propolis are metabolized and circulate in the body after oral administration of propolis.     

Aboveground productivity of an unsuccessful 140-year-old <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> plantation in northern Kyushu,Japan

We measured the aboveground biomass, biomass increment and litterfall production of a 140-year-old, abandoned Cryptomeria japonica plantation in order to infer the effects of topography on biomass production. The plantation was unsuccessful and the naturally regenerated broad-leaved trees contributed 93.4% (374.2 Mg ha⁻¹) of the total aboveground biomass (400.2 Mg ha⁻¹). Comparing between different slope positions, aboveground biomass decreased downslope corresponding to the decrease in broad-leaved tree biomass. The biomass of C. japonica did not vary with slope position. Biomass increment and litterfall production of the broad-leaved trees also decreased downslope. However, litterfall production per unit biomass and aboveground net primary production per unit biomass increased downslope. Results of a path analysis showed that biomass increment of C. japonica decreased with increasing topographical convexity, whereas biomass and litterfall production of broad-leaved tree increased. Litterfall production of broad-leaved tree decreased with increasing biomass of C. japonica, suggesting that, despite their small biomass, the presence of residual C. japonica may have negative effects on the distribution and productivity of the broad-leaved trees. Our results indicated that total aboveground biomass of the study site was comparable to that of old-growth C. japonica plantations. We inferred that the variation in aboveground biomass of the broad-leaved trees was largely determined by the topography, while their productivity was affected by interactions with planted C. japonica.     

Transgenic rice plants that over-express the mannose-binding rice lectin have enhanced resistance to rice blast

Mannose-binding rice lectin (MRL), which is almost identical to the salt-induced protein SalT, binds to mannose and glucose residues. Expression of the MRL gene in response to infection with Magnaporthe oryzae, the rice blast fungus, was stronger in the incompatible interaction than in the compatible. Transgenic rice plants that constitutively over-expressed MRL strongly suppressed the growth of invasive hyphae of the fungus on leaf sheaths and the development of typical susceptible-type lesions on leaf blades, but did not affect penetration by the fungus in comparison with the wild-type. On a polycarbonate plate, purified recombinant MRL inhibited conidial attachment and appressorium formation but not conidial germination. These results suggest that MRL may play an essential role in disease resistance by suppressing development of M. oryzae in situ.     

Somatic growth and otolith microstructure of larval and juvenile pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis>

ABSTRACT:   Microstructures of sagittae and lapilli were examined in relation to somatic growth for reared larvae and juveniles of Pacific cod. The Laird–Gompertz model was fitted to the daily age and somatic growth relationship. Growth increments were deposited on a daily basis in both kinds of otoliths, with a check formed at hatching. Two subsequent checks and an accessory primordia (AP) occurred in the sagittae. The lapillus was adequate for increment width measurement through the early life stages. Sagittal and frontal plane of sagitta was adequate for measurement in the pre-AP and post-AP formation stages, respectively. The shift of desirable plane was caused by changes in otolith and increment shapes with AP formation. Back-calculated total lengths using the biological intercept method did not significantly differ with certain body lengths ( P  > 0.05), suggesting validity of back-calculation in this species. Using the back-calculated total length, morphological and ecologic changes that seemed to affect checks and AP formations are discussed.