Reinvigoration of mature chestnut (Castanea sativa) by repeated graftings and micropropagation

Gradual reinvigoration of adult chestnut (Castanea sativa M. cv. Montemarano) shoots was obtained by serial grafting onto juvenile rootstocks. The phenomenon was evaluated on the basis of percentage of primary nodes regenerating axillary shoots and length and number of shoots (> 10 mm) per primary node. In vitro growth of explants from serially grafted shoots was significantly lower than that of explants from seedlings at the end of the establishment phase. Only microshoots from seedlings and plants that had been serially grafted four times could be subcultured on proliferation medium. Repeated subculture on medium containing a low cytokinin concentration induced progressive reinvigoration of microshoots derived from plants that had been serially grafted four times. The number of axillary shoots per explant increased significantly after six subcultures. After 12 subcultures, microshoots from serially grafted plants showed an increase in stem elongation, rooting and plantlet survival. After in vitro stabilization, there was no difference in in vitro performance between microshoots derived from seedlings and serially grafted plants. Microshoots multiplied from serially grafted plants displayed only a transitory appearance of juvenile traits.     

Deformation induced by ethanol substitution in normal and tension wood of chestnut (Castanea sativa Mill.) and simarouba (Simarouba amara Aubl.)

Wood deformation in the longitudinal and tangential directions induced by ethanol substitution and oven-drying was measured in normal wood (NW) and tension wood (TW) of chestnut (Castanea sativa Mill.) (TW with G-fibres) and simarouba (Simarouba amara Aubl.) (TW without G-fibres). The results show that with increased concentration of ethanol solution TW tends to contract, regardless of the presence or absence of G-fibres. In contrast, both NW and opposite wood expand at different rates in the longitudinal direction. These results are discussed and explained by the role of stress state at cell wall level.     

Stem taper function for sweet chestnut (Castanea sativa Mill.) coppice stands in northwest Spain

? Context

Despite the economic importance of Castanea sativa Mill. in northwest Spain, studies of its growth and yield are practically non-existent.

? Aims

A compatible system formed by a taper function, a total volume equation, and a merchantable volume equation was developed for chestnut (C. sativa Mill.) coppice stands in northwest Spain.

? Methods

Data from 203 destructively sampled trees were used for the adjustment. Outliers were removed with a non-parametric local adjustment, providing a final data set of measurements taken from 3,188 sections which was used to test five taper models (compatible and non-compatible). A second-order continuous autoregressive error structure was used to model the error term and account for autocorrelation. Presence of multicollinearity was evaluated with the condition number. Comparison of the models was carried out using overall goodness-of-fit statistics and graphical analysis.

? Results

Results show that the models developed by Fang et al. in For Sci 46: 1–12, 2000 and Kozak in For Chron 80, N 4: 507–515, 2004 were superior to other equations in predicting diameter for chestnut coppice stands.

? Conclusion

The compatible volume system developed by Fang et al. in For Sci 46: 1–12, 2000 was finally selected as it provided the best compromise between describing stem profile and also estimating merchantable height, merchantable volume, and total volume and therefore provides the first specific tool for more effective management of chestnut coppice stands.     

板栗主要栽培品种的遗传分析

应用RAPD分子标记手段 ,研究了品种间的遗传多样性。对 46个板栗品种样品的DNA ,用 16个引物进行扩增反应 ,产生 69个多态位点。结果表明 ,各个位点上遗传多样性程度存在较大差别 ,有效等位基因数目 (Ne)最大值为 1 9990 ,最小值为 1 0 44 4;基因多样度 (H)的最大值为 0 4998,最小值为 0 0 42 5 ;Shannon信息指数的最大值为 0 692 9,最小值为 0 10 47。所检测位点的平均有效等位基因数目为 1 5 2 6 0 ,平均基因多样度为 0 3618,平均信息指数为 0 4832。有效等位基因数目、平均基因多样度和平均Shannon信息指数的标准误都较小 ,分别为 0 30 96,0 1418,0 1748,估计精度较高。这 3个遗传多样性度量表明板栗品种间具有较高的遗传多样度。品种间遗传距离最大值为 0 80 0 1,相应的遗传共享度为 0 44 93;品种间遗传距离最小值为 0 0 910 ,对应的遗传共享度为 0 9130。遗传距离是评价品种间近缘关系的重要指标。对板栗品种间的遗传分析 ,是板栗良种选育和研究品种间亲缘关系的理论基础     

The effects of propagation environment on the rooting of leafy cuttings of ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.), and sweet chestnut (Castanea sativa Mill.)

The effect of propagation environment on the rooting of field collected leafy cuttings of ash (Fraxinus excelsior, sycamore (Acer pseudoplatanus) and sweet chestnut (Castanea sativa) was investigated in two experiments. In the first experiment, rooting of all three species in mist enclosed inside a polythene tent was greater than 50%, while rooting of ash cuttings was reduced from 63% in enclosed mist to only 16% in open mist. Rooting in open mist, enclosed mist, and contact polythene was studied in a second experiment. Sycamore cuttings rooted equally well in the two mist systems with an average rooting of 78%. In contrast cuttings of both ash and sweet chestnut rooted most under the enclosed mist system, at 64 and 46% respectively. Rooting of ash cuttings was again depressed in the open mist system where less than 30% of cuttings rooted. This reduction was related to an increase in the percentage of cuttings which remained alive without rooting, while showing proliferation of callus at the cutting base. The percentage of sweet chestnut cuttings which callused without rooting was also much greater in the open mist system than in enclosed mist or contact polythene.     

A multi-species comparison of delta13C from whole wood, extractive-free wood and holocellulose

The stable carbon (C) isotope composition (delta13C) of tree rings is a powerful metric for reconstructing past physiological responses to climate variation. However, accurate measurement and interpretation are complicated by diagenesis and the translocation of compounds with distinct isotopic signatures. Isolation and analysis of cellulose minimizes these complications by eliminating variation due to biosynthetic pathways; however, isolation of cellulose is time-consuming and has no clear endpoint. A faster and better-defined analytical method is desirable. Our objectives were to determine if there is a direct relationship between the isotopic compositions of whole wood (WW), whole wood treated with solvents to remove mobile extractives (extractive-free wood; EF) and holocellulose (HC) isolated by extractive removal and subsequent bleaching. We also determined if total C concentration could explain the isotopic composition and variation among these three wood components of each sample. A set of wood samples of diverse phylogeny, anatomy and chemical composition, was examined. The mean offset or difference between HC and EF delta13C was 1.07 +/- 0.09 per thousand and the offset between HC and WW was 1.32 +/- 0.10 per thousand. Equivalence tests (with alpha = 0.05) indicated that the relationship between EF delta13C and HC delta13C had a slope significantly similar to 1 +/- 5.5%, whereas for the WW delta13C: HC delta13C relationship, the slope was significantly similar to 1 +/- 10.08%. A regression model using EF delta13C to predict HC delta13C had a slope of 0.97, which was not significantly different from unity (P = 0.264), whereas the regression for WW had a slope of 0.92 which was significantly different from unity (P = 0.0098). Carbon concentration was correlated with HC:WW offset and cellulose:EF offset (P = 0.0501 and 0.007, respectively), but neither relationship explained much of the variation (r2 = 0.12 and 0.14, respectively). We suggest that HC extraction is unnecessary for most analyses of tree-ring delta13C; a simple solvent extraction is a suitable alternative for many applications.     

板栗BFD(百腐敌)保鲜剂的研制及应用

通过多种药剂影响板栗耐贮性试验 ,筛选出了一种多功能复合保鲜剂BFD (百腐敌 ) ,对不同分散剂提高保鲜剂保鲜效果进行了试验 ,确定了其最佳配方及生产工艺流程和最佳使用浓度 ,并进行了多年、多点、多品种保鲜效果试验和毒性测定及营养成份分析。结果表明 :BFD保鲜剂处理栗果可延缓采后衰老 ,兼具杀虫、杀菌多种功能。采用保鲜剂适宜浓度处理栗苞 ,室温条件下贮藏 10 0～ 12 0d ,鲜果率 95%以上 ;坚果经保鲜剂处理后低温库贮藏 12 0～ 180d ,鲜果率 96%以上。贮后紧果色香味匀佳 ,营养成分同刚采下的坚果相近 ,含糖量增加。BFD性能稳定、使用方便 ,投资少 ,价格便宜 ,不污染环境 ,对人畜低毒 (LD50大于 50 0 0mg/kg)且可自行分解 ,适合大面积推广应用。     

Preparation and characterization of the phenolated wood using hydrochloric acid (HCl) as a catalyst

Summary Birch (Betula maximowicziana Regel) wood meal was liquefied in the presence of phenol using hydrochloric acid (HCl) as a catalyst at a temperature of 150 °C for 2 h in an autoclave. It was found out that HCl acid could be used as an effective catalyst for the hydroxy phenylation of wood under the experimental conditions. In this study the effect of the concentration of the acid catalyst and the phenol-to-wood ratio on the liquefaction were investigated. The results showed that the phenol-to-wood ratio and the concentration should be increased to a certain degree in order to achieve a less residual rate and sufficient amount of combined phenol. The phenolated woods had apparent flow temperatures in the range of 134.4 to 199.8 °C, being higher than that of a commercial novolak resin. Furthermore, increases in the HCl concentration during liquefaction reaction led to increase in the apparent flow temperature of the resulting phenolated woods. However, the changes in the liquid ratio did not bring about evident changes. The relationship between shear stress (τ) and shear rate showed that the phenolated wood resin melts were shear thinning fluids. The dependences of the apparent melt-viscosities (η) of the phenolated woods and a commercial novolak resin on the shear rates ( ) have the similar tendencies, however, it was found the viscosities of the phenolated woods are about one order higher than that of commercial novolak resin.     

Application of cure-accelerated phenol-formaldehyde (PF) adhesives for three-layer medium density fiberboard (MDF) manufacture

 This study was conducted to optimize hot pressing time and adhesive content for the manufacture of three-layer medium density fiberboard (MDF) through the cure acceleration of phenol-formaldehyde (PF) adhesives by adding three carbonates (propylene carbonate, sodium carbonate, and potassium carbonate) in the core layer. Carbonate type, carbonate level, PF resin content, and hot pressing time were evaluated on the basis of the performance of MDF panels prepared. The application of cure-accelerated PF adhesives by the addition of propylene carbonate reduced both PF resin content and total hot pressing time by 38% and 29%, respectively, for the manufacture of quality three-layer MDF panels (19.1 mm thickness) under the hot-pressing temperature of 205 °C. The optimum concentration of propylene carbonate for cure acceleration of PF resin was found to be 3 wt% by weight based on the resin solids. Bending properties, on one hand, were independent of carbonate type and level, and complied with the minimum requirements by ANSI. Internal bond (IB) strength, on the other hand, was closely related with carbonate types and level used. Received 13 March 1999     

短枝型板栗品种(优系)性状分析与评价

为了解短枝型板栗品种和优系特性,对7个短枝型板栗品种(优系)在幼树生长结果、栗实品质等方面进行了调查分析,采用平均隶属度方法进行短枝型板栗品种(优系)的分析评价。结果表明,参试品种(优系)在生长结果、栗实外观以及营养品质等方面,有一定或较大差异。根据平均隶属度排序结果,‘下港短枝’、‘燕山短枝’、‘泰山短枝-10’综合性状较好,建议生产中推广应用。     

Structural, histochemical and chemical characterization of normal, tension and opposite wood of Subabul (Leucaena leucocephala (lam.) De wit.)

Structure, histochemistry and chemical composition of tension (TW), opposite (OW) and normal wood (NW) of Leucaena leucocephala have been studied using histological, histochemical and biochemical methods. TW vessels are longer and have a larger diameter than NW vessels, and the rays are shorter and thinner. The G-layer replaced S3 and parts of S2 wall layers in TW fibres. TW further contained less lignin that also had a lower syringyl-to-guaiacyl ratio. The lignin was also more condensed. The content of α-cellulose was high in TW. TW contains hemicelluloses and pectins composed of more galactose, and less xylose, mannose, 4-O-methylglucuronic acid and galacturonic acid compared to that of OW. This study suggests that in the TW of Leucaena, the amount and composition of lignin, hemicelluloses and pectins differ considerably from that in OW and NW.     

Development of new natural polymer-based wood adhesives I: dry bond strength and water resistance of konjac glucomannan,chitosan, and their composites

 Bonding properties of konjac glucomannan (KGM), chitosan, and their composites were investigated. After preparing three-ply plywood glued with these materials, the dry bond strength and the bond strength after water immersion treatment were measured. The bond strength of urea-formaldehyde resin adhesive, casein, and soybean glues was also studied for comparison. KGM developed relatively good dry bond strength in extremely small solid amounts, irrespective of alkaline treatment. However, the water resistance was extremely low for all of the conditions. Chitosan also developed good dry bond strength in small solid amounts and was better than conventional adhesives. Chitosan also exhibited excellent water resistance compared to casein and soybean glues. When KGM and chitosan were combined, the adhesiveness under the dry condition was enhanced, and the bonding properties were superior to those of casein and soybean glues. Therefore, it is expected that chitosan and chitosan–KGM composite can be used as environmentally friendly wood adhesives. Received: March 18, 2002 / Accepted: July 5, 2002 RID="*" ID="*" Part of this paper was presented at the 51th Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

Radial growth and characterization of juvenile and adult wood in plantation grown okoumé (Aucoumea klaineana Pierre) from Gabon

The fast-growing hardwood, okoumé (Aucoumea klaineana Pierre), is a major forest species in Gabon and is used principally for making plywood, but research into the growth and quality of this wood is scanty. Trees from natural forests are favoured for production, yet little information exists on wood characteristics from plantation trees. Therefore, we carried out a dendrochronological study along with measurements of wood longitudinal modulus of elasticity (E _L ), density (D _w ), dimensional stability parameters (longitudinal, radial and tangential shrinkage and fibre saturation point) and fibre cell morphology to determine if these properties were related to age in trees from two plantations. We then used segmented regression analysis to define the limit (breakpoint) between juvenile (JW) and adult wood (AW). Using monthly precipitation data, we were able to determine that one growth ring is formed per year, composed of a large light coloured ring formed during the long rainy season and a thick, dark band formed during the major dry season. However, thinner bands, analogous to false rings, may also form during the short dry and short rainy seasons. Ring width decreases from the pith to the bark, and the breakpoint between JW and AW was at 19 years old when trees from both plantations were pooled together. No differences in D _w or radial and tangential shrinkage occurred with cambial age. E _L increased significantly up to the cambial age of 12–14 years, after which the increase with age was only slight and no breakpoint between JW and AW was found. With regard to mean longitudinal shrinkage, AW was found to form after the age of 13 years but fibre cell length was significantly longer after the age of 14.5 and 20 years, depending on the plantation of origin. Therefore, the boundary between JW and AW in plantation grown okoumé occurs between the ages of 13 and 20 years, depending on the characteristic examined.     

A review on wood machining: characterization,optimization, and monitoring of the sawing process

ABSTRACT

Sawing is the most common machining process and is present in both primary and secondary wood transformation sectors. The objective of this paper is to review how it is affected by different factors. The current challenges associated with various machining factors, process monitoring, and sensor selection were identified and explained. Consequently, four research challenges and technological gaps were outlined. (1) Contradictory results have been reported due to different cutting processes, wood species, measurement methods, and cutting speed range studied in literature, so special consideration needs to be taken when comparing results with those available in the literature. (2) Laboratory test conditions cannot yet fully represent the extreme cutting conditions in sawmills. More emphasis should be placed on those harsh industrial cutting conditions. (3) Research on wood cutting lacks multi-objective optimization approach, which suggests that sawdust generation should be simultaneously analysed with surface quality and power consumption. (4) Compared with metal cutting, little research has been conducted on wood sawing monitoring using an artificial intelligence approach, which should be prioritized in designing adaptive control systems. Combining intelligent monitoring and multi-objective optimization approaches should pave the way for controlling the sawing process so higher surface quality and cost efficient machining is achieved.