Reaction of manganese peroxidase ofBjerkandera adusta with synthetic lignin in acetone solution

The reaction of manganese peroxidase (MnP) of the white-rot fungusBjerkandera adusta with synthetic lignin dehydrogenation polymer, DHP) in acetone medium was investigated. Gel-permeation chromatography of the DHP treated by MnP demonstrated depolymerization of syringyl DHP in the reaction mixture containing 70% acetone; moreover, concomitant repolymerization occurred to give highly polymerized products. Guaiacyl DHP was only repolymerized by MnP in the same acetone solution without giving degradation products. Addition of ascorbic acid to reaction mixtures containing acetone resulted in preferential depolymerization of syringyl DHP.Part of this report was presented at the meeting of Kansai Branch, Japan Society for Bioscience, Biotechnology, and Agrochemistry in Kagawa, October 1996     

Development of Eucalyptus clones for a summer rainfall environment with periodic severe frosts

Eucalyptus grandis, E. grandis hybrid, and E. saligna hybrid trees, developed through as many as four generations of selection in southern Florida, were naturally exposed to exceptionally low winter temperatures. In a genetic base population and related field studies, 100 phenotypically superior cloning candidates were selected after an 8-h freeze with a low of –11 °C. Following propagation as rooted cuttings, 55 clones (typically 11–42 ramets per clone) were outplanted in a single-tree plot design and evaluated for 3.8 years which included two additional severe freezes. Significant clonal variation was observed in frost resilience, vigor, and quality. After composite evaluation for frost resilience, size, and form, only three clones were considered suitable for operational planting. Selection of further clones for outplanting requires major commitments to locate candidates and to test them. Field testing for frost resilience requires considerable investment, much beyond the requirements for developing fast-growing clones alone. Clones identified by testing will not be resistant to freezing conditions but will be resilient and greatly reduce the risks now associated with plantation culture in southern Florida.(requests for offprints)     

A contribution to the pollen morphology for arboreal type of caesalpinioideae in Korea

The pollen morphology of 7 taxa of three genera of the subfamily Caesalpinioideae in Korea was investigated by light microscope (LM) and scanning electron microscope (SEM). The pollen grains of this subfamily are monads, prolate spheroidal or subprolate, and trizonocolporate. Sculpture pattern is reticulate or perforate. Based on sculpture pattern, colpus width and grain shape at equatorial view, 4 major pollen types of the subfamily are discernible;Caesalpinia, Cercis, Gleditsia I, andGleditsia II. This study was supported by Korean Academic Promotion Foundation. During this study, Botanic Garden of Kyoto University, Japan, Anmyondo Arboretum and Dr. Byongsoo Kang at Dongkuk Univ., Korea provided materials and informations which are greatly appreciated.     

Malaysianol A, a new trimer resveratrol oligomer from the stem bark of Dryobalanops aromatica

A new resveratrol trimer, malaysianol A (1), five known resveratrol oligomers: laevifonol (2), ampelopsin E (3), α-viniferin (4), ε-viniferin (5), diptoindonesin A (6), and bergenin (7) have been isolated from the acetone extract of the stem bark of Dryobalanops aromatica by combination of vacuum and radial chromatography techniques. Their structures were established on the basis of their spectroscopic evidence and comparison with the published data. The cytotoxic activity of the compounds was tested against several cell lines in which compound 4 was found to inhibit strongly the growth of HL-60 cell line.     

A study of the potential of hedgerow intercropping in semi-arid India using a two-way systematic design

The potential of hedgerow intecrropping with Leucaena leucocephala was explored on vertic Inceptisols over 4 years at ICRISAT Center, Patancheru, India. The study was conducted using a systematic layout involving different alley widths ranging from 1.35 to 4.95 m and with varying distances between hedge and crops. The alleys were cropped with alternate rows of sorghum and pigeonpea. Hedges composed double Leucaena hedgerows 60 cm apart were periodically harvested for fodder. Sole crops of all components and a sorghum/pigeonpea intercrop were included in all four replications of the study.Starting in the second year, Leucaena was progressively more competitive to annual crops, causing substantial yield reduction. Competition (primarily for moisture) was most severe in narrow alleys and was greatest on pigeonpea.The growth of Leucaena was not sufficient to compensate for reduced crop yields. Land equivalent ratios (LERs) calculated on the basis of grain yield of crops and Leucaena fodder yields showed that hedgerow intercropping (HI) was advantageous over sole crops only during the first two years using wide alleys, but disadvantegeous in the last two years. LERs calculated on the basis of total dry matter indicated only a small advantage for HI (13–17 percent) over sole crops in wider (>4 m) alleys. Average returns per year from HI exceeded those of the most productive annual crop system (sorghum/pigeonpea intercropping) by 8 percent in 4.05 m alleys, and by 16 percent in 4.95 m alleys. Fodder production during the dry season was 40 percent of the annual total in these alley widths. Thus hedgerow intercropping at 4–5 m alley width is not very attractive for farmers in semi-arid India, which has 600–700 mm of annual rainfall. There is a need to examine the potential of HI in wider alleys. The merits and limitations of the systematic design are discussed.     

The use of ethylene diffusers is comparable to treatments with sprayed ethylene to reduce the damage caused by the olive moth (<Emphasis Type="Italic">Prays oleae</Emphasis> Bern.)

In 2002 and 2003, six field experiments were conducted at three olive groves of southern Spain in order to compare the effects of two types of ethylene treatments (sprayed and diffusers) on the olive losses caused by the olive moth (Prays oleae Bern.) as well as on the activity and effectiveness of oofagous predators. Both treatments showed to be effective to control the pest; in the two years studied the mean reduction in final infestation due to ethylene was of 35% with respect to the controls trees, and none affected negatively the action of natural predators of P. oleae. In addition, the use of diffusers set on the trees at the end of flowering period will help the farmers to overcome the problems of determination of optimum time for sprayed treatments of ethylene.     

A tree/crop interface design and its use for evaluating the potential of hedgerow intercropping

The paper describes a tree/crop interface (TCI) experiment designed to investigate the effects of row orientation using Leucaena leucocephala Lam. Each TCI plot consisted of a regularly pruned Leucaena hedge in the middle and 12 crop rows on either side. Eight such plots were arranged at 45° around a sole Leucaena plot with rows oriented in four compass directions viz., North-South, East-West, Northeast-Southwest and Northwest-Southeast.Results of four years from 1984 to 1987 did not show any effect of row orientation, and similarly, no effect was seen on crop rows due to their location on the windward or leeward side of the hedge. The TCI effect was positive on the first crop row in the first year because Leucaena grew slowly, but depressed the yield of the first 4 to 6 crop rows(1.8 to 2.7 m from hedge) in subsequent years. The negative effect of Leucaena was noted more on sunflower in a relatively dry year than on sorghum in other years.Results from the TCI plots were used to estimate the yield of five hedgerow intercropping (HI) systems with varying alley widths (2.7 to 9.9 m). Comparison with sole stands of Leucaena and crops indicated that HI was more productive particularly at close alley widths. For example, hedges spaced at 2.7 m and 3.6 m averaged 37% and 25% higher productivity than the respective sole stands; but this advantage may be an overestimation of the real potential.The relevance of TCI experiments for studying agroforestry systems, their merits and limitations, especially of the design employed in this study are discussed.     

Responses ofQuercus sapwood to infection with the pathogenic fungus of a new wilt disease vectored by the ambrosia beetlePlatypus quercivorus

Quercus serrata andQ. crispula wilt during the summer in wide areas along the Sea of Japan. Mass attacks of trees by an ambrosia beetle (Platypus quercivorus) are characteristic before appearance of the wilting symptoms. This study investigated the pathogenic effects of a fungus detected specifically in the wilting trees. This hyphomycete fungus,Raffaelea sp., has a distribution that correlates with the discolored xylem area called wound heartwood in which vessels are dysfunctional. Tylosis formation around the hyphae indicates vessel dysfunction. In areas with discoloration, the fungal hyphae were invading living ray parenchyma cells from the vessel lumen. As a protective reaction the ray cells exuded yellow substances into the vessels, but these substances seemed ineffective against the fungal activity, probably because the fungus disperses along the beetle's gallery before enough substance can accumulate. It should allow wide discoloration in sapwood. Cambium was not necrotic around the fungus. The cytological process in the host was as follows: (1) synthesis of secondary metabolites by the stimuli of oak fungus; (2) exudation of yellow substances into vessels; and (3) dysfunction of vessels and wound heartwood formation. In regard to wilting of trees, the pathogenicity of the fungus should be assessed by its ability to stop sap flow.     

A provisional growth model with a size–density relationship for a plantation of <Emphasis Type="Italic">Paraserianthes falcataria</Emphasis> derived from measurements taken over 2 years in Pare,Indonesia

A growth model for a plantation of Paraserianthes falcataria was provisionally derived from measurements of 32 permanent plots taken over a period of 2 years in Pare, Indonesia. This model first predicts height growth with the polymorphic site index equation. Then density-related growth and mortality, that is, diameter and stand density, are calculated to satisfy the mathematical relationship for the reciprocal and self-thinning equations, both of which were based on the maximum size–density line with the slope of −1.759 identified in this study. Cumulative predictions on diameter and stand density, starting with each of three age classes, 3, 4, and 5 years after planting, and continuing for the next 2 years, agreed well with the observations of age-class mean. An exception was for stands that were 7 years old, which were marginal, but closest to the rotation age of 8 years. Contrasting height/diameter relationships among the three age classes were described reasonably well with this model, and the predicted basal growth area was found to agree fairly well with observations. These results suggest that the growth model presented here has good potential for applying size–density control for plantations of P. falcataria. However, measurements for an additional few years might be necessary to derive a model that will more accurately predict diameter size at the rotation age.     

A trial to detect optimal pin-pricking timing in evaluating the ability to form traumatic resin canals of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> for selecting resistant trees to <Emphasis Type="Italic">Semanotus japonicus</Emphasis> (Coleoptera: Cerambycidae)

A trial to detect optimal pin-pricking timing in evaluating the ability to form traumatic resin canals (TRCs) of Cryptomeria japonica was examined to select resistant trees to Semanotus japonicus using 14 clones in 2001 and 2002. Resistance to S. japonicus and the ability to form TRCs in the phloem was evaluated by inoculating newly hatched larvae in the bark and by a pin prick, which was conducted every 10 days (four times) on the trunk around the larval phloem-feeding period, respectively. The larval survivorship varied greatly among clones for both years. The mean appearance of newly formed TRCs was generally higher in late treatment for both years, and the tangential width of them was also higher in 2001, whereas those of pre-formed TRCs were not higher for either year. The larval survivorship did not show significant correlations with the appearance and the width of pre-formed TRCs on all treatments. However, it showed significant negative correlations with the appearance of newly formed TRCs on the second and third treatments on the 2-year-old layer, although this was not significant with the width of them. This suggests that resistant clones might have the mechanism of rapidly forming TRCs when just at the stage of newly hatched larval entering the phloem. Thus, although the relationship between the appearance and the width of newly formed TRCs is not clear, pin-pricking treatment when the newly hatched larvae just enter the bark may be one of optimal times for the evaluation of the resistance of C. japonica to S. japonicus. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The supply of matrix containing glucomannans to the innermost surface of S2 layers is associated with changes in turgor pressure of differentiating tracheids in Cryptomeria japonica

We investigated the relationship between turgor pressure and diurnal differences in secondary wall formation of differentiating tracheids. Saplings of Cryptomeria japonica were grown in a growth chamber with 12-h light:12-h dark cycles, and the tangential strain on the inner bark surface was measured as an indicator of the volumetric changes of differentiating cells. The innermost surface of developing secondary walls was then observed using field emission scanning electron microscopy at 1-h intervals after both light and dark periods. Dramatic changes in the aspects of the innermost surface of developing secondary walls occurred 3h after the light was switched on and 4h after the light was switched off. The amorphous material containing glucomannans became evident when the differentiating cells became fully turgid during the dark period. Conversely, cellulose microfibrils became clearly visible when the cell volume was low during the light period. These results suggest that the diurnal periodicity in the supply of hemicellulose-containing matrix to developing secondary walls is associated with the changes in turgor pressure of differentiating tracheids that result from the change in light conditions during the photoperiodic cycle.     

Verification for generalizability and accuracy of a thinning-trees selection model with the ensemble learning algorithm and the cross-validation method

For the purpose of making a highly effective model in relation to the selection of trees for thinning for various forestry goals, the author examined the generalizability and accuracy of models using various ensemble learning algorithms and the m-fold cross-validation method. These techniques make it possible to improve discrimination accuracy by combining or integrating multiple learning results whose accuracies are not very high. WEKA, which is a machine learning tool for data mining programmed in Java machine language, was used to verify the results of the simulation models. The number of samples was 503. Pattern-recognition algorithms in this study used five classification-type models and one function-type model. It was found that: (1) without cross validation, two pattern-recognition algorithms can be classified as having comparatively high discrimination accuracy; (2) with cross validation, discrimination accuracy decreased as a whole, but was not very different from that without cross validation, and (3) from the viewpoint of generalizability, we constructed a model at around 70% discrimination accuracy. In order to construct more effective models, we need to design the model to utilize certain algorithms or to build in re-sampling methods such as ensemble learning and cross validation. Additionally, in the case of small sample datasets, ensemble learning is an effective method for constructing efficient models. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Formation and chemical structures of acid-soluble lignin II: reaction of aromatic nuclei model compounds with xylan in the presence of a counterpart for condensation,and behavior of lignin model compounds with guaiacyl and syringyl nuclei in 72% sulfuric acid

To elucidate the formation and chemical structures of water-soluble material in acid-soluble lignin (ASL), lignin aromatic nuclei model compounds of creosol (I) and 5-methoxycreosol (II) were reacted with xylose or xylan in the presence of apocynol as a counterpart for condensation in 72% sulfuric acid (SA). The reaction of I gave mainly condensation product. However, the condensation reaction of II with apocynol was suppressed because of steric hindrance from the methoxyl group, and II yielded a C-xyloside after refluxing in 3% SA together with condensation products. To obtain information on CHCl₃-soluble material in ASL, model compounds of arylglycerol--aryl ethers with guaiacyl (VIII) and syringyl (X) nuclei were treated by the Klason procedure. VIII gave only insoluble polymerized product, while X gave insoluble polymerized product and CHCl₃-soluble low molecular weight products, which were dissolved in 3% SA. These results prove earlier views that water-soluble material in ASL consists of condensation products formed from syringyl lignin and monosaccharide units in hemicellulose. In addition, the CHCl₃-soluble material in ASL appears to be composed of low molecular weight degradation products from SA treatment of Klason lignin with the syringyl nucleus.Part of this report was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001 and at the 47th Lignin Symposium, Fukuoka, October 2002, and was reviewed in Mokuzai Gakkaishi (2002) 48:55–62