Radial and between-family variations of the microfibril angle and the relationships with bending properties in Picea jezoensis families

With emphasis on tree breeding for wood quality in Picea jezoensis, we aimed to evaluate radial and between-family variations in the microfibril angle (MFA) of the S₂ layer in the latewood tracheids in 10 open-pollinated families of 43-year-old P. jezoensis trees. In addition, the relationships between MFA/wood density with the modulus of elasticity (MOE) or modulus of rupture (MOR) were investigated. Significant differences in MFA between families were found from the pith toward the bark. MFA showed higher values around the pith area, although some families showed relatively lower values than others around this area. In addition, due to a larger coefficient of variations of MFA near the pith, the potential for juvenile wood MFA improvement may be greater compared with mature wood. MOE was correlated with MFA in juvenile wood and with wood density in mature wood, whereas MOR was mainly correlated with wood density at radial positions in both woods. Therefore, to improve the MOE and MOR of P. jezoensis wood, both MFA and wood density would be factors to consider in both juvenile and mature woods. On the other hand, there are indications that, only wood density would be an important criterion for improving mature wood properties.     

Effect of high molecular weight carbohydrates on bud cell formation by <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> in potato dextrose broth

Potato dextrose broth (PDB), one of the most popular culture media for fungi, can be made in the laboratory from potato extract and glucose (handmade PDB) and also bought as powder (commercial PDB). We compared growth of Fusarium oxysporum in handmade and commercial PDBs. For seven strains tested, bud cell formation and fungal biomass were higher in handmade PDB than in commercial PDB. Gel filtration analyses revealed that handmade PDB contained carbohydrates with molecular weights >20 MDa, while most carbohydrates in commercial PDB were <45 kDa. Freshly prepared, raw potato starch had a molecular weight >20 MDa and enhanced bud cell formation by five of seven strains when added to commercial PDB. The addition of glucose to commercial PDB promoted biomass production but not bud cell formation. Furthermore, in a semisynthetic medium containing raw potato starch, bud cell formation was enhanced for all strains tested. These results indicate that the high molecular carbohydrates present in raw potatoes enhanced bud cell formation by Fusarium oxysporum.     

Effects of polyphenols from seed shells of Japanese horse chestnut (Aesculus turbinata BLUME) on methotrexate-induced intestinal injury in rats

The purpose of this study was to evaluate the effects of polyphenols from seed shells of Japanese horse chestnut (JHP) on methotrexate (MTX)-induced intestinal injury in rats. MTX application caused intestinal morphological injury and increase in malondialdehyde (MDA) levels, decrease in levels of glutathione (GSH) and glutathione peroxidase (GSH-Px) activities in small intestine. However, oral administration of JHP ameliorated MTX-induced intestinal injury and inhibited the increase in MDA and the decrease in GSH and GSH-Px activity in small intestine. In conclusion, our results indicated that oral administration of JHP alleviated MTX-induced intestinal injury through its antioxidant properties.     

Stimulatory effect of aluminum on the growth of tea pollen tubes

It is well known that when inorganic elements such as boron (B), calcium, cobalt, and manganese are added to media in combination or alone, they stimulate the germination and/or tube growth of various kinds of pollen (Schmücker 1933; Loo and Hwang 1944; Yamada 1958; Brewbaker and Kwack 1963). Among these elements, the stimulatory effect ofB is the most effective and generally recognized. Aluminum (Al) belongs along with B to Group IIIa in the periodic table, and Fähnrich and Ultlich (1964) reported that Al inhibited the germination and growth of the pollen tube of Petunia hybrida and Antirrhinum majus. However, stimulatory effects of Al on pollen germination or pollen tube growth had not been previously reported.     

Effect of aluminum on callose synthesis in root tips of tea (Camellia sinensis L.) plants

Aluminum (Al) toxicity is a major factor limiting yield production on acid soils (Foy 1983). The initial symptom of Al toxicity in many plants is manifested by the inhibition of root elongation (Ownby and Popham 1990; Llugany et al. 1994; Sasaki et al. 1994; Horst et al. 1997), which occurs during a very short period of time after exposure to Al (Llugany et al. 1994; Staß and Horst 1995). In a large number of recent reports, it was shown that the root apex plays a major role in the Al-sensitivity and response mechanisms (Zhang et al. 1994; Sasaki et al. 1997; Sivaguru and Horst 1998). However, it is interesting to note that stimulatory effects of Al on the growth of plants have also been reported in some studies (Chenery 1955; Konishi et al. 1985; Huang and Bachelard 1993; Osaki et al. 1997). In tea plant (Camellia sinensis L.) a stimulatory effect of Al on the growth was also demonstrated in some experiments, using intact plant (Chenery 1955; Konishi et al. 1985), cultured roots (Tsuji et al. 1994), and pollen tubes (Yokota et al. 1997). The growth of tea roots was typically more stimulated than that of shoots by Al (Konishi et al. 1985). It was assumed that Al effects might be due to the amelioration of phosphorus absorption (Konishi et al. 1985), secretion of malic acid from roots to dissolve aluminum phosphate in the rhizosphere (Jayman and Sivasubramaniam 1975), stimulation of growth of microorganisms on the root surface (Konishi 1990) or replacement of some functions of boron (Konishi 1992; Yokota et al. 1997). However, the stimulatory effects of Al on tea plant growth have not yet been el ucidated.

The formation of callose (1,3-β-glucan) has been reported as a common plant response to a variety of stresses, as well as mechanical, biophysical, chemical, and biological injury (Jaffe and Leopold 1984; Zhang et al. 1994). Increased synthesis of callose has been observed upon exposure to excess amounts of some elements, such as boron (McNairn and Currier 1965), cobalt, nickel, zinc (Peterson and Rauser 1979), and manganese (Wissemeier and Horst} 1987, 1992). Callose synthesis was also induced by Al in the roots of Triticum aestivum (Zhang et al. 1994) and Zea mays (Horst et al. 1997; Sivaguru and Horst 1998), suspension-cultured cells of Glycine max (Staß and Horst 1995), and protoplasts of Avena sativa (Schaeffer and Walton 1990) and Zea mays (Wagatsuma et al. 1995). Induction of callose synthesis in roots seems to be a very rapid physiological indicator of Al-induced injury or genotypical differences in Al sensitivity (Wissemeier and Horst 1992; Zhang et al. 1994; Horst et al. 1997). Nevertheless, Al-induced callose synthesis in tea plant, whose growth is stimulated by suitable Al concentrations, has not been described yet. Therefore, to elucidate the physiological basic effects of Al on tea plant, callose synthesis affected by Al in the root tips of intact plants was analyzed in the present study.     

Induction of liver microsomal UDP-glucuronyltransferase in the rat administered with a plant phenol, eugenol

UDP-glucuronyltransferase activity toward xenobiotics in rat liver microsomes was increased about 2.6-fold by administration of a eugenol (4-allyl-2-methoxyphenol). Km value of the induced enzyme toward UDP-glucuronic acid, however, did not change. Immunoblotting analysis revealed that the amount of UDP-glucuronyltransferase protein was increased in the microsomes of eugenol-treated rat liver. In vitro translation assay showed that the level of translatable mRNA encoding this enzyme increased in the liver. These results indicate that mRNA specific for production of UDP-glucuronyltransferase has accumulated, presumably by de novo synthesis in response to a plant phenol, eugenol.     

Effect of the gut microflora on chick growth and utilisation of protein and energy at different concentrations of dietary protein

The effect of the gut flora on chick growth and protein and energy utilisation at a marginal dietary energy level (calculated metabolisable energy value 11.7 MJ/kg) was determined with diets containing 227 or 293 g protein/kg. Germ-free (GF) and conventional (CV) chicks were reared for 10 d on the diets, and excreta were collected during the last 4 d. The chicks were killed and carcases and droppings were analysed for N and fat. The GF chicks grew significantly faster than the CV controls on both diets. The growth of CV chicks given the high protein diet was similar to that of GF chicks given the adequate protein diet. Protein and energy utilisation were significantly less for CV than for GF chicks on both diets. It was concluded that the energy requirement of CV chicks was greater than that of their GF counterparts, and that their poorer growth was due to utilisation of some dietary protein as an energy source.     

转型中的亚洲林业(续二)

在过去的20年里,亚洲林业经历了引人注目的转型,包括从计划经济到市场经济的转变,从天然林供给木材到人工林供给木材的转变,木材替代品与非木质林产品的增加,地方分权与当地群众的参与,生态时代的发展与生态系统管理。在促进亚洲可持续森林资源管理中,市场工具、社区参与和环境服务都得到了应用。亚洲林业的转型表现出多样化,其森林、社会与环境之间的联系是丰富多彩的。     

Changes in the relationship between tree size and aboveground respiration in field-grown hinoki cypress (Chamaecyparis obtusa) trees over three years

Respiration measurements of aerial parts of 18-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) trees were made under field conditions over three years to study changing relationships with tree age between respiration and phytomass, phytomass increment, and leaf mass. The relationship between annual respiration (r(a)) and phytomass (w(T)) was approximated by a proportional function (r(a) = aw(T)), where the proportional constant (a) decreased year by year. The effect of time on the relationship between annual respiration and phytomass of each sample tree was fitted by a power function. Respiration of the tree suppressed by the canopy decreased year by year, but respiration of the other trees increased slightly with age. The relationship between annual respiration and leaf mass was also approximated by a generalized power function. Excluding the suppressed tree, the relationship between annual respiration (r(a)) and the annual increment of aboveground phytomass (Deltaw(T)) was described by a proportional function (r(a) = 2.27Deltaw(T)), where the proportional constant, 2.27, was independent of sample tree and year, indicating that about 2.3 times of the annual aboveground phytomass increment equivalent was respired annually. For any tree, the time constant relationships between annual respiration and leaf mass and phytomass increment for different-sized trees were similar to the corresponding time continuum relationships. In contrast, the time continuum relationship between annual respiration and phytomass differed from the time constant relationship, indicating that respiration of less active woody tissue contributed significantly to aboveground respiration. Based on the relationship between tree size and annual respiration, annual aboveground stand respiration was estimated to be 25.0, 26.9, and 25.8 Mg(dm) ha(-1) year(-1) for the three consecutive years, respectively, and the corresponding aboveground stand biomass was 60.0, 69.0, and 76.8 Mg(dm) ha(-1).