Cytological and genetical studies on male sterility inCryptomeria japonica D. Don

Genetic male sterility is a useful trait in plant breeding, especially in angiosperm crops such as corn, onion and carrot. We found a male sterile sugi (Cryptomeria japonica D. Don) tree in Toyama, Japan. Pollen of sugi is one of the major causes of pollinosis in Japan. We carried out this research in an attempt to make clear the characteristics and inheritance of this male sterility. Microsporogenesis of the male sterile tree proceeded meiosis, however, the microspores collapsed after they were separated from pollen tetrads in locules, resulting in complete male sterility. Most likely, ethylene evolution was responsible for male sterility expression. Full seed setting in the male sterile tree indicated normal macrosporogenesis. Seeds obtained from crossing between male sterile and normal lines showed relatively high level of germination and their seedlings grew vigorously. The somatic chromosome numbers of 241 germinated seeds, derived from the male sterile tree, were mostly 22, euploid. These results indicated that male sterile tree was different from other similar previously reported trees with low pollen fertility, resulting from triploid or trisomics. Probably, male sterility in sugi is either nuclear genetic male sterility or cytoplasmic male sterility. The study was partially supported by Program for Promotion of Basic Research Actives for Innovative Biosciences.     

Development of an air-injection press for preventing blowout of particleboard II: improvement of board properties using small-diameter holes for air injection

An air-injection press, which has holes punched in the heating plates, injects high-pressure air through the holes of one plate into boards during press heating. The air-injection press can manufacture boards from high-moisture-content particles by controlling blowouts of the boards. In this study, boards were manufactured from particles that had a moisture content of 25% by using the air-injection press, which reduced the required pressing time. Boards manufactured by injecting air through holes of 5 mm in diameter were of poor quality with a low internal bond strength of only 0.31 MPa. When the hole diameter was reduced to 1 mm, the internal bond strength increased to 0.44 MPa. A high air-injection pressure of 0.55 MPa also resulted in improved board properties over those for boards manufactured at lower pressures. This was probably because a large amount of binder was released from boards through the 5-mm holes, together with water vapor, during air injection; the small-diameter holes reduced the release of binder, resulting in better board properties.     

Development of an air-injection press for preventing blowout of particleboard V: effects of board density and thickness on property of board manufactured from high-moisture particles

Particleboards with thickness of 10 mm and densities of 0.6, 0.7 and 0.8 g/cm³ were manufactured from high-moisture particles using urea–formaldehyde resin and the effectiveness of air injection was examined. The temperature in the 0.6 and 0.7 g/cm³ boards was lower with air injection than without during the initial to middle stages of pressing, while the temperature in the 0.8 g/cm³ board remained lower with air injection than without throughout the entire pressing process. Air injection reduced the pressing time required to manufacture the 0.6 and 0.7 g/cm³ boards and also increased the internal bond strength of boards of all densities. In the 0.6 and 0.7 g/cm³ boards, air injection reduced the modulus of rupture (MOR), while in the 0.8 g/cm³ boards, the MOR was similar between those manufactured by injecting and not injecting air. Air injection was also found to be effective for boards of high densities. The effectiveness of the air injection on thick boards was investigated by manufacturing 20-mm-thick boards of 0.7 g/cm³. Without air injection, it was not possible to manufacture the 20-mm-thick boards, even by extended hot pressing, but air injection allowed the boards to be manufactured by pressing for 16 min. Air injection was also shown to be effective for manufacturing thick boards.     

Performance of particleboard manufactured using air-injection press II: effects of board density and thickness on the performance of board manufactured from low-moisture particles

Particleboards of different densities (0.6, 0.7 and 0.8 g/cm³) and thicknesses (10 and 20 mm) were manufactured from low-moisture particles using an air-injection press. The effects of the air injection on preventing blowout of the boards of different densities and thicknesses were investigated by artificially creating blowout-prone conditions using metal frames. The effects of the air-injection pressure on the board performance were also investigated. 10-mm-thick boards of 0.8 g/cm³ pressed at 170 °C blew out when air was not injected, but were successfully manufactured by injecting air. 10-mm-thick boards at 150 °C showed constant internal bond (IB), regardless of density, but at 170 °C, IB was higher in boards of higher densities. This was likely due to accelerated hardening of the urea–formaldehyde resin at 170 than 150 °C. At both pressing temperatures, low air-injection pressure did not cause blowout and a reduction in board performance. Air injection also prevented the blowout of thick boards of 20 mm and enabled successful manufacture, showing its effectiveness. The IB of the 20-mm-thick board manufactured using the air-injection press exceeded that of 20-mm-thick board manufactured using an ordinary hot press.     

Effects of sealed pressing and ozonization on properties of styrene-butadiene rubber and polyethylene glycol adhesive bonded board produced by two-stage pressing

Boards were produced by using SP adhesive, which contains styrene-butadiene rubber and polyethylene glycol as major constituents. The use of polyethylene in place of clay, which is also a generally used constituent of SP adhesive, was confirmed to improve board properties. In general, the properties of boards are poorer when produced by two-stage pressing, in which mats are first processed by temporary adhesion and then processed into boards by permanent adhesion; however, the properties of boards produced by two-stage pressing were improved when polyethylene was added to the SP adhesive. In addition, internal bond strength and thickness swelling was greatly improved when boards were produced from ozonized wood and by sealed pressing. Thus, the properties impaired by two-stage pressing were improved by ozonization and sealed pressing.     

日本北海道北部寒温带森林流域林冠层凋落物及其养分归还量的景观格局(英文)

Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.     

Distribution of boron in wood treated with aqueous and methanolic boric acid solutions

The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)₃] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)₃ was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)₃ was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281     

Dimensional stability and strength properties of particleboard produced by a closed-press system

The purpose of this study was to reveal the effects of various levels of mat-moisture content (m.m.c.) and the closed-press system for making single- or three-layer particleboard on the density profile, thickness swelling, specific moduli of elasticity (MOE) and rupture (MOR) and internal bond strength. Internal gas pressure was measured in an enclosed frame; and the larger the m.m.c., the higher the internal gas pressure became. When rising water vapor (steam) struck particles, it plasticized them and cured the adhesive, resulting in improved interparticle contact. The vertical density gradient in the three-layer board was larger than that in the single-layer board. As for thickness swelling by cold-water soaking, the single-layer boards were less affected than the three-layer boards and showed good dimensional stability with increased m.m.c. The open-system boards swelled more than the closed-system boards. The closed-system single-layer board made at high m.m.c. returned nearly to the prime thickness by air-drying after cold-water soaking. Specific MOE and MOR were larger at 15% or 10% m.m.c. than those at other m.m.c. Considerable reductions of specific MOR and MOE of the closed-system three-layer board were observed at 20% or 25% m.m.c.Part of this report was presented at the 45th annual meeting of the Japan Wood Research Society, Tokyo, April 1995 and at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

Antioxidant, anti-hyaluronidase and antifungal activities of Melaleuca leucadendron Linn. leaf oils

The present study examined the chemical composition, in vitro antioxidant, anti-hyaluronidase and antifungal activities of essential oils of Melaleuca leucadendron Linn. from Gundih-Central Java, Indonesia in different plant ages of 5, 10 and 15 years old. The Chemical composition of essential oils were analyzed by GC/MS. Twenty-six components were identified, of which 1,8-cineole (49.22–55.04 %), α-terpineol (8.79–10.70 %), d-limonene (5.58–6.39 %), and β-caryophyllene (5.03–7.64 %) were the main compounds in these oils. The antioxidant assay and anti-hyaluronidase assay showed that M. leucadendron leaf oils possess mild antioxidant activity with IC₅₀ between 7.21 and 9.23 mg/ml and anti-hyaluronidase activity with IC₅₀ between 1.94 and 3.03 mg/ml. The antifungal assay showed the effectiveness of these essential oils against Fomitopsis palustris (IC₅₀ 0.12–3.16 mg/ml), Trametes versicolor (IC₅₀ 0.01–0.06 mg/ml), Cladosporium cladosporioides (IC₅₀ 0.03–0.49 mg/ml), and Chaetomium globosum (IC₅₀ 0.06–0.15 mg/ml).     

Preparation and properties of oligoesterified wood blocks based on anhydride and epoxide

Summary Preparation and properties of oligoesterified woods in the form of block are reviewed. The oligoesterified wood blocks are prepared by stepwise addition reactions of dicarboxylic acid anhydride and epichlorohydrin (EpCl), or one-step chemical treatment with reactant solution of the anhydride and EpCl. Among the preparation methods investigated, the heating-suction method is industrially advantageous. In this method, wood blocks impregnated with the reactant solution are heated and then subjected to suction under reduced pressure and heating, to remove unreacted reactant solution. The oligoesterified wood blocks thus obtained contain oligoester chains formed by the alternate additions of the anhydride and EpCl to OH groups of wood. They also contain small amounts of free oligomers not linked with the wood matrix. Their dimensional stabilities against moisture and water become greater with increase in the apparent total weight increase due to the oligoester chains and the free oligomers. The oligoesterified wood blocks based on phthalic anhydride-EpCl are industrially promising, and exhibit higher compressive and flexural strenghts, greater chemical resistance, electric insulation, and much lower water absorption than untreated wood block. Furthermore, excellent resistances are observed against weathering and biodeterioration.