Rates of chemical weathering of porous rhyolites: 5-year measurements using the weight-loss method

To examine the rate of chemical weathering, field experiments using microweight-loss techniques were carried out. Two kinds of porous rhyolite forming lava domes in Kozu-shima Island were selected: (1) a younger rock (weathering period is 2.6 ka) and (2) an older rock (20 ka). Both rocks seem to have been very similar in their initial composition and structure. They have, however, different properties in the present depending on the difference in weathering period. Rock tablets of these rhyolites with a diameter of 3.5 cm and a thickness of about 1 cm were enclosed in a nylon mesh bag and placed in a soil–bedrock interface on a hillslope of central Japan for over 5 years. The younger rock has a lower weight loss by about 0.5%, and the older rock has a higher weight loss of 3% to 5%. These results show that older rock has a higher rate of chemical weathering than in younger rock. This supports Oguchi et al.'s (Oguchi, T.C., Hatta, T., Matsukura, Y., 1994. Changes in rock properties of porous rhyolite through 40,000 years in Kozu-shima Island, Japan. Geogr. Rev. Jpn. 67A, 775–793 (in Japanese, with English Abstr.); Oguchi, T.C., Hatta, T., Matsukura, Y., 1999. Weathering rates over 40,000 years based on changes in rock properties of porous rhyolite. Phys. Chem. Earth (A) 24, 861–870.) finding that the rate of change in chemical properties appears to accelerate with weathering time.     

Characteristics of fertilizer uptake and biodistribution in strawberry plants in two Japanese cultivars in hydroponic culture

ABSTRACT

The fertilizer absorption characteristics of strawberries are not clear, although appropriate fertilization is definitely necessary to ensure produce quality and quantity. This study aimed to determine the amounts of macro- and micronutrients absorbed during cultivation of strawberries and their biodistribution and utilization in the plant body. We cultivated Japanese strawberries ‘Benihoppe’ and ‘Kirapika’ in small hydroponic equipment containing a nutrient solution and determined the amounts of N, P, K, Ca, Mg, Fe, Mn, B, Zn, Cu, and Mo absorbed during and at the end of cultivation. The results revealed the adsorption levels of these elements during the cultivation period. The nutrient concentrations varied greatly among plant organs. In particular, P and B accumulated at high levels in the leaves and stem, K, Ca, Mg, Mn, Zn, and Cu accumulated in the crown, and N, Fe, and Mo accumulated in the roots. In addition, the uptake levels of N, P, K, Mg, Mn, Zn, and Cu differed between Benihoppe and Kirapika. Our results provide useful information for determining fertilizer application rates in strawberry cultivation.     

Extended glucuronidation is another major path of cyanidin 3-O-beta-D-glucopyranoside metabolism in rats

We previously determined that five rather hydrophobic metabolites appeared in blood plasma after oral administration of cyanidin 3-O-beta-D-glucopyranoside, but a group of hydrophilic metabolites still remained unidentified. In the present study, 12 hydrophilic metabolites found were collected from urine and plasma samples by high-performance liquid chromatography (HPLC) and then analyzed by tandem MS spectrometry. From the MS spectra, four metabolites out of 12 were assigned as glucuronides of cyanidin 3-O-beta-D-glucopyranoside and six out of 12 were glucuronides of the primary metabolites of cyanidin 3-O-beta-D-glucopyranoside (O-methyl cyanidin 3-O-beta-D-glucopyranoside). Extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and O-methyl cyanidin 3-O-beta-D-glucopyranoside showed their maximum plasma concentrations at 15 and 60 min (or 30 min) after oral administration, respectively. Their maximum plasma concentrations ranged from 15 to 70 nM. From the profile of urinary-excreted anthocyanins after intravenous administration, it was deduced that extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and O-methyl cyanidin 3-O-beta-D-glucopyranoside were mainly produced in the liver rather than by intestinal flora. The area under the plasma concentration curve was 0.25 micromol min/L for extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and 0.14 micromol min/L for O-methyl cyanidin 3-O-beta-D-glucopyranoside, respectively, when evaluated as cyanidin 3-O-beta-D-glucopyranoside equivalent, indicating that extended glucuronidation is a critical pathway in cyanidin 3-O-beta-D-glucopyranoside metabolism in rats.     

Contribution of insulin to the ascorbate recycling system in the chicken liver

The effect of insulin on the ascorbate recycling system in the chicken liver was examined. First, insulin was injected subcutaneously into the chicken, and liver glutathione‐dependent dehydroascorbate reductase (GSH‐DHAR) activity was determined. Insulin increased liver GSH‐DHAR activity, but did not affect plasma and liver ascorbate concentration. Dehydroascorbate increased plasma and liver ascorbate levels, and liver GSH‐DHAR activity. However, distinct changes in plasma insulin level were not observed by dehydroascorbate injection. In addition, reduction of external dehydroascorbate in cultured chicken hepatocytes could not be observed in an insulin‐deprived culture, although the cells reduced external dehydroascorbate in a serum‐free culture with insulin. We concluded that insulin affects the ascorbate recycling system as an essential factor in the chicken liver.     

Identification of putative defense-related genes in Japanese pear against <Emphasis Type="Italic">Alternaria alternata</Emphasis> infection using suppression subtractive hybridization and expression analysis

The Japanese pear pathotype of Alternaria alternata, a toxin-dependent necrotrophic pathogen, causes black spot of Japanese pear by producing the host-specific AK-toxin. Pre-inoculation with nonpathogenic A. alternata or pretreatment with an elicitor prepared from A. alternata reduced disease symptoms caused by the pathogen. Salicylic acid- and jasmonic acid-dependent signaling pathways are not involved in the induced resistance to infection by the pathogen. The expression of multiple defense-related genes in Japanese pear leaves inoculated with nonpathogenic A. alternata was examined using suppression subtractive hybridization. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank database as accessions DC993229–DC993535.     

Studies on availability and fixation of phosphorus in soil (part 4)

It Is known that inorganic phosphorus is contained in soil mainly in the form of calcium phosphates, aluminium phosphates and iron phosphates.     

Effect of the strain combination of the donor and recipient on the production efficiency of W‐bearing sperm in mixed‐sex germline chimeric chickens

Effect of the strain combination of the donor and recipient on production efficiency of W‐bearing sperm in mixed‐sex chimeric testes was analyzed. The combinations of the donors and recipients were White Leghorn (WL) and Rhode Island Red (RIR), and vice versa. Generated mixed‐sex chimeras that had the male phenotype at sexual maturity were classified into four groups: (1) a female WL donor and a male RIR recipient; (2) a male WL donor and a female RIR recipient; (3) a female RIR donor and a male WL recipient; (4) a male RIR donor and a female WL recipient. The mean number of W‐bearing sperm detected by in situ hybridization among 10 000 sperm observed were 147, 165, 30 and 45 in groups 1, 2, 3 and 4, respectively. The numbers in groups 1 and 2 were both significantly higher than those of groups 3 and 4 (P < 0.05). The combination of a WL donor and a RIR recipient produced W‐bearing sperm more efficiently than the reverse combination.     

Stimulation of axillary shoot formation of cuttings of Hylocereus trigonus (Cactaceae) by pre-soaking in benzyladenine solution

Either before or after curing their cut surfaces for 5 days, 7 cm- and 15-cm-long decapitated Hylocereus trigonus cuttings were treated by soaking their apical or basal ends in benzyladenine (BA) solution. They were then planted and grown in a greenhouse.For the 7 cm-long cuttings, BA (25–100 mg l^?1) applied to the apical ends for 24 h increased the ratio of cuttings with sprouted buds to 64–100%, the number of sprouted buds to 1.9–3.1 and of shoots to 1.6–2.8, and the shoot length to 35–60 mm, compared to the water control which showed 13%, 1.0, 1.0 and 12.5 mm, respectively. Soaking the basal part had only a small effect.Naphthylacetic acid (NAA) applied to the basal ends of cuttings immediately after cutting increased the number of sprouted buds and shoots by inducing early rooting. The number and length of BA-induced axillary shoots in the longer cuttings was greater than those in the shorter ones.In the 15-cm-long cuttings, increasing the soaking time from 5 min to 24 h resulted in a greater promotive effect of BA on shoot formation. BA applied before curing showed the same effect as that given after curing but caused necrosis of the tissue just under the cut surface. Enlarging the area soaked in BA solution from 5 cm to 10 cm decreased the number of sprouting buds and shoots.