Root growth enhancement by rhizospheric aluminum treatment in Quercus serrata Thunb. seedlings

This article discusses the effect of aluminum on root growth of Querucus serrata Thunb. In a 9-week hydroponics experiment, the effects of various concentrations (0 to 5.0 mM) of Al on root growth were examined. Results revealed that root biomass increases with the increase in Al concentration up to 2.5 mM, and then it tended to decrease. In the next experiment, the effects of H⁺ and Al³⁺ on roots were compared in a 4-week hydroponics experiment using three treatment solutions: control (pH 6.0), −Al (without Al, pH 3.5), and +Al (with 2.5 mM Al, pH 3.5). No clear difference in the biomass and root length between the control and −Al treated roots was observed, and root and shoot biomass were increased by Al treatment. These results confirmed that the H⁺ concentration level, at a pH of 3.5, is not toxic for Q. serrata and the Al-induced increase in root biomass is not caused by the amelioration of H⁺ toxicity by Al. In the third experiment, roots were exposed to an Al solution (pH 3.6) intermittently. This treatment clarified that Al stimulated rooting and root elongation. In the fourth experiment, the effect of 1 mM Al on root growth during a 15-month period in a sand culture were examined. This experiment confirmed that Al stimulated good growth and development of root systems at appropriate concentrations. Therefore, it is considered that Al-induced root growth enhancement occurs as a long-term and short-term phenomenon.     

Chemical modification of wood by non-formaldehyde cross-linking reagents

Summary Using sulfur dioxide (SO₂) as catalyst, wood specimens were treated with nonformaldehyde cross-linking reagents such as glyoxal, glutaraldehyde and dimethylol dihydroxy ethyleneurea (DMDHEU). The results of dimensional stability, acoustic properties, and mechanical strength tests were compared with those obtained from formaldehyde treatment. With glyoxal and glutaraldehyde treatments, antiswelling efficiency (ASE) reached around 70%, which is comparable to the values attained by formaldehyde treatment, although the accompanying weight gain was much larger than for the latter, whereas DMDHEU did not give sufficiently high ASE. None of the treatments, significantly increased specific dynamic Young's modulus (E/) with the exception of the DMDHEU treatment, loss tangent (tan ) decreased substantially, about 50 and 60% in longitudinal and radial directions respectively, which were somewhat exceeding the formaldehyde treatment. The results suggested that the improvement of the dimensional stability and acoustic properties is partly attributed to the formation of cross-links.     

Termite repellent sesquiterpenoids from Callitris glaucophylla heartwood

Fractions of methanol and ethanol extracts from the heartwood of white cypress pine (Callitris glaucophylla Thompson et Johnson) were investigated for their repellent activity against subterranean termite Coptotermes formosanus Shiraki worker using a two-choice semicircular filter paper test at 0.5% (w/w) concentration. Fraction CY-E2 composed of (−)-citronellic acid, guaiol, α-, β-, and γ-eudesmol isomers as well as an unknown compound, showed the highest statistically significant repellency (97.8% ± 2.2 SEM) of all fractions tested. Bioactivity-guided fractionations using high-performance liquid chromatography led to the isolation of two, oxygenated eudesmane-type sesquiterpenes with α-methylene moieties, both termite-repellent compounds. These compounds were subsequently identified as ilicic acid methyl ester (IAME) and costic acid by means of spectroscopic analyses, electron impact mass spectrometry, and nuclear magnetic resonance spectroscopy. We report the isolation of both IAME and costic acid from C. glaucophylla heartwood for the first time. Part of this paper was presented at the 47th Symposium on the Chemistry of Terpenes, Essential Oils, and Aromatics, Tokyo, November 2003     

Pore structure and the properties of electric double layer capacitor electrode of bamboo-derived activated carbon prepared by superheated steam

Bamboo-derived activated carbon prepared by superheated steam (BAC) exhibited performance for utilization as an electric double layer capacitor (EDLC) electrode. Pore structure and EDLC performances were investigated by comparison with phenol resin-derived activated carbon (MSP-20), which is commercially available and often used for the purpose. The nitrogen adsorption isotherm showed that BAC had a large BET-specific surface area of 1268 g/m² with a developed pore structure, especially of the mesopore, in comparison with MSP-20. It is considered that inherent ash in bamboo promoted activation, in addition to physical activation by superheated steam. Capacitance per electrode volume (C_V) was 52 F/cm³ with BAC. Because the density of BAC is high (0.78 g/cm³) compared with that of MSP-20 (0.58 g/cm³), sufficient C_V for usage was obtained, although the capacitance per electrode mass (C_M) at 5 mA/cm² itself of BAC (67 F/g) was lower than that of MSP-20 (126 F/g). With IR drop, the resistance value of BAC (9.7 Ω) was lower than that of MSP-20 (10.5 Ω). Especially, the diffusion resistance of BAC disclosed to be smaller than that of MSP-20. These results indicated that BAC produced by steam activation is a promising material with a pore structure suitable for ion transfer in EDLC.     

Effects of Yuzu (Citrus junos) Peel from Waste as an Aquaculture Feed Supplement on Growth,Environmental Load,and Dark Muscle Discoloration in Yellowtail Seriola quinqueradiata

Beneficial utilization of yuzu (Citrus junos) peel was investigated to improve the commercial value of cultured yellowtail fish. The antioxidant effects of grated yuzu peel from pomace (yuzu paste) on prevention of dark muscle discoloration during storage in sliced yellowtail fish were tested. Four diets were prepared, containing 0, 10, 50, and 100 g yuzu paste in a 1,450-g diet (wet basis). Fish were fed one of the four diets for 10 weeks. Growth performance was not significantly different among the dietary groups, but fish fed a diet containing 100-g yuzu paste showed the least average body weight and a significant increase in fecal amount and fat levels in the feces, which suggest low digestibility and low absorption. Dark muscle discoloration was significantly reduced in all yuzu dietary groups compared to the control group during storage at 4°C. The optimal supplementation of yuzu paste in the fish diet is very effective at maintaining fish flesh freshness as a finishing diet without causing additional phosphorus or nitrogen pollution of the sea and inhibiting fish growth. This study provides a new way to utilize waste yuzu peel, which also helps reduce waste from yuzu processing.     

Bacterial leaf blight of sweet pepper (Capsicum annuum) caused by Pseudomonas cichorii in Japan

Sweet peppers (cv. Tosajishi beauty) with leaf blight symptoms were observed in Kochi Prefecture, 2003. Initially, small spots formed on leaves, and later enlarged to brown to dark brown spots, and eventually blighted leaves fell. Several bacteria that caused the same symptoms were isolated and subsequently reisolated. These bacteria were identified as Pseudomonas cichorii on the basis of bacterial characteristics and the 16S rRNA gene sequence. This is the first report of bacterial leaf blight in the sweet pepper in the world.     

Heartwood extractives from the Amazonian trees <Emphasis Type="Italic">Dipteryx odorata,Hymenaea courbaril</Emphasis>, and <Emphasis Type="Italic">Astronium lecointei</Emphasis> and their antioxidant activities

Heartwood extracts from Amazonian trees cumaru-ferro (Dipteryx odorata), jatoba (Hymenaea courbaril), and guarita (Astronium lecointei) exhibit antioxidant activities comparable with that of α-tocopherol, a well-known antioxidant. This article reports the characterization of the antioxidant compounds in the extracts of the three heartwoods. Silica gel column chromatography of the cumaru-ferro EtOAc extract yielded (−)-(3R)-7,2′,3′-trihydroxy-4′-methoxyisoflavan and (+)-(3R)-8,2′,3′-trihydroxy-7,4′-dimethoxyisoflavan. Silica gel column chromatography followed by preparative high-performance liquid chromatography of the jatoba EtOAc extract yielded (−)-fisetinidol and (+)-trans-taxifolin. Chemical structures were assigned using electron-ionization mass spectrometry, ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy including nuclear Overhauser effect spectroscopy (NOESY), as well as optical rotation and circular dichroism. Gas chromatography-mass spectrometry demonstrated that the isolated compounds were predominant in the EtOAc extracts. In the guarita EtOAc extract, catechin and gallic acid were identified by comparing their retention times and mass fragmentation patterns with those of authentic samples. Antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl assay demonstrated that all these compounds had activities comparable with that of α-tocopherol. Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007