Influence of the Age of Bamboo Culm and Its Vertical Position on the Technological Properties of Bamboo Fibers: A Case of Bambusa vulgaris Species from Cameroonian Culture

Due to their interesting properties, bamboo fibers are more and more used as reinforcements in polymer matrices as a substitute for synthetic fibers. For their future service life, it is important to understand their physical and mechanical behavior over time in order to control the aging phenomenon within this fiber. The paper analyzed the influence of the age of the bamboo thatch and the vertical position of the Bambusa vulgaris species cultivated in Cameroon on the physicomechanical properties of the fibers extracted from the thatch. Fibers were mechanically extracted from three bamboo culms aged respectively 3 years (BV3), 4 years (BV4) and 5 years (BV5). The culms were thus identified according to their number of ramifications, and were felled no abated for a total of three culms. A section of about one meter on each of the parts (lower part, middle part, upper part) of these three culms was made for the opposite technological studies. Each age was therefore represented by three portions of thatch, one from the upper part, one from the middle part and the last from the lower part of the thatch, all giving a total number of nine samples taken and marked BV3inf, BV3moy, BV3sup, BV4inf, BV4moy, BV4sup, BV5inf, BV5moy, BV5sup before handling in the laboratory. Physical (density, moisture absorption rate) and mechanical (tensile tests according to DIN EN ISO 13934-1, natural durability) characterizations were used to better understand the mechanisms of this influence. In view of all the results obtained, the fiber from the upper part of the 3-year-old thatch (BV3sup) is the one with the best characteristics and is recommended for a better elaboration of bamboo fiber composites: (Density: 0.83;Absorption rate 11.7%;Young’s modulus: 7.4 GPa;Maximal stress: 64.3 MPa;Elongation at rupture: 1.1;Loss of mass natural durability: 7.63%).

Changes in culm surface temperature with maturity of the bamboo species Guadua angustifolia

We used thermal images of bamboo culms of Guadua angustifolia Kunth to analyze the relationship between culm surface temperature and maturity, driven by the hypothesis that young culms may exhibit lower surface temperatures than old ones. The culm surface temperature shows small but constant differences between three age classes of 1, 2, and 3 years. Our findings indicate that surface temperature may be applied as an additional indi- cator to support the determination of maturity of guadua culms besides the visual assessment of the culms.

Seasonal effect on rooting behaviour of important bamboo species byculm cuttings

We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2-3 node culm cuttings in three growing seasons viz. spring （March）, summer （June） and rainy （August） from superior candidate plus clumps （CPCs） centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting （78.89%）, followed by B. vulgaris （74.44%）. In general, the potential of different bamboo species for rooting was found to be in the order： B. bambos 〉 B. vulgaris 〉 B. balcooa 〉 D. hamiltonii 〉 B. tulda 〉 D. strictus 〉 D. giganteus 〉B. nutans. The maximum rooting was recorded in spring （56.67%）, which was closely followed by summer （54.58%）. In winter season, minimum rooting （36.67%） was observed. The interaction effect of species x season was also significant on sprouting and rooting pa- rameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda （43.8） during spring season.

Solar-powered Bamboo Culm Prefabricated Housing

The solar-powered hybrid energy system has been put into practice in Hunan bamboo culm prefabricated housing and was enrolled in this study.In this paper,the experimental data which was taken from a demonstration house highlighted that this system has a high potential for integrated solar energy utilization.The average thermal efficiency of the collector was 58.68%,and the thermal conductivity coefficient of bamboo culm prefabricated composite wall was 1.075 W/(m2 K).Based on these results,bamboo culms could be used as the main structural material and heat storage slow-release flooring in the prefabricated housing.The housing was lower in energy consuming.

Assessing Growth Parameters from Culm Cuttings of Bambusa vulgaris at the University of Dschang Botanic Garden, West Region of Cameroon: Implications for the Bamboo Resource Base and Rural Livelihoods

Dwindling supplies of bamboo resources and the increase in the demand for bamboo have led to the need for better propagation techniques. This is the only way to ensure the sustainability of the bamboo resource base and improve livelihoods. Thus, this study was carried out to examine the different growth parameters of culm cuttings of Bambusa vulgaris in propagation beds with a substrate consisting of dark soil, manure (compost) and sand in a ratio of 1:1:1. Data on different growth parameters was collected on a daily basis over a three week period and analyzed using appropriate descriptive and inferential statistics. It was found that the different growth parameters (diameter, height, leaves and sheaths) of culm cuttings of B. vulgaris evolved in like manner in three propagation beds. Descriptive statistics for growth parameters of culm cuttings of B. vulgaris showed little or no differences across three shelter/propagation beds (shelter bed 1, shelter bed 2 and shelter bed 3) with 1.4675 ± 1.6172 cm, 93 ± 112 cm, 22 ± 30 leaves, and 4 ± 6 sheaths being the mean diameter, height, number of leaves and number of sheaths for all three propagation beds, respectively. ANOVA test showed no statistically significant variation (p > 0.05) between growth parameters of culm cuttings of B. vulgaris across the three propagation beds, implying that the different growth parameters were relatively similar. Pearson correlation showed the existence of direct and inverse relationships between the different growth parameters of culm cuttings of bamboo. The existence of these direct and inverse relationships could be attributed to the rapid growth rate of bamboo, the substrate used, and the species of bamboo used (B. vulgaris). The study recommends more large-scale propagation projects of this bamboo species in order to ensure the sustainability of the bamboo resource base and improve livelihoods of bamboo dependent rural communities.

Elastic Buckling of Bionic Cylindrical Shells Based on Bamboo

High load-bearing efficiency is one of the advantages of biological structures after the evolution of billions of years. Biomimicking from nature may offer the potential for lightweight design. In the viewpoint ofrnechanics properties, the culm of bamboo comprises of two types of cells and the number of the vascular bundles takes a gradient of distribution. A three-point bending test was carried out to measure the elastic modulus. Results show that the elastic modulus of bamboo decreases gradually from the periphery towards the centre. Based on the structural characteristics of bamboo, a bionic cylindrical structure was designed to mimic the gradient distribution of vascular bundles and parenchyma cells. The buckling resistance of the bionic structure was compared with that of a traditional shell of equal mass under axial pressure by finite element simulations. Results show that the load-bearing capacity of bionic shell is increased by 124.8%. The buckling mode of bionic structure is global buckling while that of the conventional shell is local buckling.

Comparison of three processing methods for laminated bamboo timber production

Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time(32.1 min), followed by the SS-method(18.2 min), and the SE-method(17.9 min). However, the VG-method showed the highest recovery(82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method(49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.

Morphological phylogeny among 15 accessions of bamboos growing in Kokrajhar district of the Bodoland Territorial Area Districts,Assam

Bamboo is nature＇s wonderful gift historically associated with the rural population of the Bodoland Territorial Area Districts.However,indiscriminate use of the resource and the ambiguity in the identification of bamboos in the absence of flowering characters pose a potential risk to the bamboo germplasm.Therefore,we considered revising the taxonomic positions and phylogenetic relationships among 15 tropical bamboo species using 35 key morphological descriptors（MD） to assess the reliability of vegetative characters in identifying species.The phylogenetic tree constructed from the similarity matrix,derived from an unweighted pair group method of analysis（UPGMA） of the 35 MDs,marginally deviated from the conventional taxonomic positions of the bamboo species.While the two varieties,one forma of Bambusa vulgaris（var.Vittata,var.Vulgaris,fo.Waminii） and two species of the genus Dendrocalamus（D.giganteus and D.hamiltonii）clustered together in a single clade,and D.strictus was distantly placed from their congeners.This discrepancy with the conventional classification might have ensued since only vegetative characters such as culm anatomy,culm sheath,leaf,and leaf sheath were considered in the present study.While the phylogenetic relationship among the 15 tropical bamboos（computed from exhaustive MDs）grossly corroborate the conventional taxonomic grouping,a molecular-marker-based multidisciplinary approach should resolve the remaining conflicts in bamboo identification.

基于制片竹秆软化方法研究

【目的】为了探讨不同软化方式对竹材结构和主要组分的影响,筛选适合不同研究目的的最佳软化方法。【方法】以厚竹(Phyllostachys edulis‘Pachyloen’)竹秆为研究对象,采用常规石蜡制片结合显微技术和紫外光谱分析技术进行研究。【结果】除了三甘醇和氢氟酸软化的材料容易破裂外,水以及其他化学试剂软化均可获得较为完整、清晰的竹秆结构。且乙二胺为竹秆显微切片制备的最适软化介质。【结论】10%乙二胺100℃水浴软化最为方便快捷,适于以结构研究为目的,木质化程度高的竹类植物显微制片。对于竹秆组成成分研究,纯水100℃水浴软化为最佳选择。该文为竹材利用基础研究提供了参考依据。

毛竹及其2种变异类型叶结构特征研究

【目的】为了揭示毛竹(Phyllostachys edulis)及其2种变异类型厚竹(Ph.edulis‘Pachyloen’)、八字竹(Ph.edulis‘Bicanna’)叶的功能差异,及其与竹秆形态特征之间的关系。【方法】采用石蜡制片法结合显微技术观察叶片的解剖结构特性,构建其三维形态结构图,利用蒽酮比色法测定相关生理指标。观测各竹种竹秆的秆形因子变化规律,并进一步分析了叶结构与秆形特征之间的关系。【结果】毛竹叶面积、泡状面积、维管束面积更大,且具有更厚的下表皮、叶片、叶肉,其叶的结构更有利于光合作用;毛竹和厚竹叶的结构和秆形特征密切相关。【结论】毛竹叶片结构特征更有利于光合作用,积累更多物质用于竹秆生长,且毛竹和厚竹可通过改变叶片和秆形特征来权衡资源,从而维持自身正常生长。该文为进一步揭示竹子生长发育机制奠定基础,并为竹子新种质创制提供科学依据。

月月竹竹秆变色后全长转录组分析

为探究月月竹竹秆受到光照由绿色变为紫色的分子机制,本研究采集月月竹同一竹节紫色部分(Z)、渐变部分(M)和绿色部分(L)的竹青,提取RNA,利用PacBio Sequel三代全长转录组测序技术,结合生物信息学方法对不同颜色的竹青进行全长转录组分析。结果表明,经过三代测序和数据质量控制,共获得非冗余转录本66961条,长度为500~3000 bp,平均长度1389.22 bp,序列总长度为93.02 Mbp,N50为1830 bp,G+C碱基含量为49.56%。利用NR、Swiss-Prot、COG、GO、KEGG和Pfam数据库对所有转录本进行功能注释,共有56938条转录本被成功注释,占全部转录本的85.03%;49115条转录本被GO注释,其中催化活性、细胞器、代谢过程分别是GO数据库分子功能、细胞组分和生物过程中含转录本最多的项目;28231个转录本被KEGG数据库注释,其中与碳水化合物代谢和基因翻译相关的转录本最多。结合GO注释和KEGG注释,66961条转录本中有381条转录本与光信号的感受、传递以及光调控相关,包括红光和远红光的受体蛋白PHYA、PHYB及信号通路蛋白PIF3、ELF3,蓝光的受体蛋白CRY、ZTL及信号通路蛋白COP1、SPA1、ELF3、GI、HY5等。类黄酮(包括花青素)代谢、叶绿素合成、类胡萝卜素合成等与植物色素合成相关通路分别含有转录本187条、44条和72条。全长转录本共获得2079个转录因子,其中包括18个由35个转录本编码的与花青素合成相关的R2R3MYB转录因子。CNCI、CPC、Pfam、PLEK等数据库同时注释到的长链非编码RNA(LncRNA)6359个,数量高于孝顺竹等其他竹种。本研究获得了高质量的月月竹竹青全长转录组数据,与竹秆变色相关的红光和蓝光受体及光信号传递蛋白,与花青素、叶绿素和类胡萝卜素合成相关的转录因子及长链非编码RNA(LncRNA),为进一步深入分析月月竹竹秆变色机制提供基础。

料慈竹秆形性状变化规律

料慈竹因竹材质量好、节间长而备受关注。秆形性状是影响竹材利用效率的关键因素。为探明料慈竹秆形性状与竹丛性状的关系,在四川省江安县、叙永县的料慈竹纯林中共设置12个样地,测量样竹的竹节数、节长、节中径、壁厚等性状。经曲线拟合和相关性分析,得出料慈竹秆形性状变化规律。结果表明:(1)料慈竹竹节数量大多为21~29节,最长节可达128 cm,平均为94.42 cm;(2)最长节相对位置在秆高0.36~0.58处,平均值是0.47,大部分样地间无显著性差异;(3)随着竹节相对高的升高,料慈竹节长表现为“短—长—短”对称抛物线的分布特征;竹节壁厚递减,呈显著负相关关系;(4)竹节体积占整株体积的比例由下往上呈“少—多—少—极少”的抛物线分布特征;(5)样地间最长节体积差异与竹丛性状差异趋势一致。基于料慈竹的节长和竹节体积在立竹中的占比均表现出抛物线的分布规律,具有一定对称性,料慈竹的最长节指标可作为优良品种选育的判断因子。

笋竹两用林培育管理技术研究

为了进一步提高毛竹产量、保证毛竹品质,本文结合研究区实际,从林地选择及复垦,林分构建,科学施肥、水分管理、根部覆盖、钩梢管理、林间道修建和地下竹鞭调控、采伐及留竹等毛竹林的管理,采笋时间及规格、采笋方法,有害生物预防、治理等多个方面,对毛竹的笋竹两用林培育技术进行分析,为毛竹产业的发展提供技术参考。

厚皮毛竹厚壁性状的表型遗传分析

厚皮毛竹原产地和引种地表型遗传变异稳定。分析了其生物量/胸围系数、竹壁厚度、秆壁率和地上部生物量分配,初探了厚皮毛竹起源。

毛竹林老竹水平和经营措施对新竹发育质量的影响

毛竹林是我国重要的森林资源类型,在森林固碳和林业应对气候变化中具有不可替代的重要作用。由于毛竹林的持续采伐与自我更新特性,在竹林经营过程中,新竹的发育数量和质量成为评价竹林固碳功能变化的决定性因子。利用两因素随机区组设计,排除地形因子等影响,选取施肥和采伐留养方式这两个因素,研究老竹水平和经营措施对2010年和2013年毛竹林新竹发育质量的影响。结果表明:无论2010年还是2013年,新竹平均胸径、株数和碳储量与3年生和5年生老竹的相关性均高于2年生和4年生老竹。新竹碳储量与3年生和5年生老竹碳储量呈线性相关,建立线性回归模型y=0.675x-2.2491,R^2=0.8561,而新竹碳储量与2年生和4年生老竹碳储量相关性较低,线性回归模型为y=-0.1109x+6.7287,R^2=0.0061。不同经营措施实施后,新老竹之间关系发生了很大的改变,新竹平均胸径与老竹的相关性大幅下降,新竹株数和碳储量与老竹几乎没有相关性,新竹碳储量与3年生和5年生老竹碳储量的线性回归模型为y=0.1036x+3.7539,R^2=0.0981,新竹碳储量与2年生和4年生老竹碳储量的线性回归模型为y=-0.0408x+5.9069,R^2=0.0151。不同经营措施的实施对新竹的平均胸径、株数和地上碳储量产生了很大的影响。处理A_1B_2(大量施肥中度采伐中密度留养)、A_2B_2(中等施肥中度采伐中密度留养)和A_3B_2(不施肥中度采伐中密度留养)新竹平均胸径、新竹株数和新竹碳储量都有所增加,新竹平均胸径增幅为:处理A_2B_2(8.78%)>A_1B_2(2.43%)>A_3B_2(2.06%),新竹株数增幅为:处理A_1B_2(81.0%)>A3B2(35.4%)>A2B2(15.2%),新竹地上碳储量增幅为:处理A_1B_2(90.8%)>A_3B_2(35.7%)>A_2B_2(49.7%),而其余处理基本都会减少,说明适度采伐留养最有利于提高毛竹林新竹的发育质量。仅仅从固碳最大化的角度出发,大量施肥中度采伐中密度留养最有利于新竹碳储量的增加,而从培养大径竹材的角度考虑,中等施肥中度采伐中密度留养能收到更好的效果。

立地条件对毛竹生物量的影响研究

通过对江西省14个毛竹主产区不同立地条件毛竹生物量的研究结果表明,海拔与立竹度、胸径、郁闭度和竹腔厚显著相关;竹高随土壤厚度、全N和有机质含量增加而增高,坡位与竹高、胸径和竹腔厚显著相关;在一定范围内,郁闭度随土壤有机质、全N、速效P和速效K含量增加而增加,而随海拔和土壤厚度增加而降低;竹材重量随海拔升高而减小,海拔和速效P对竹材重量影响达差异显著;有机质和全N含量与物种多样性呈正相关关系,母岩和土壤质地对物种多样性的影响差异显著;影响竹材杆壁厚大小的立地因子依次为全N、母岩和速效N,并随其含量的增大而增厚,同时方差分析表明,不同母岩和全N含量的竹材杆壁厚存在显著差异。

云南主要竹材材性与制浆造纸性能分析

对云南的10种主要竹材的竹壁进行制片和离析,系统地进行了纤维形态观察、统计分析以及化学组成成分和抽出物的测定,综合分析评价了竹材的造纸性能,筛选出了适合造纸的竹种:龙竹、黄竹、慈竹、昆明实心竹、梨藤竹、沙罗单竹等,为竹材在造纸上的合理利用提供了依据。

毛竹顺纹方向力学性能的试验研究

以毛竹圆竹和竹片为研究对象,研究其顺纹方向的力学性能.通过41个试件的试验研究,获得了毛竹竹片顺纹方向的弹性模量、抗压强度、抗拉强度以及毛竹圆竹顺纹方向的抗压强度和抗剪强度等力学指标,所有强度计算结果转化成含水率为12%时的强度,以消除含水率差异的影响.结果表明:竹材顺纹抗拉强度略大于抗压强度,以圆竹和竹片为测试单位测得毛竹竹材的顺纹抗压强度相差不大,竹节对竹材的抗压强度提高不明显,对抗拉强度和抗剪强度有所削弱.研究还提出了试件破坏现象及原因,为竹结构房屋设计与进一步理论分析提供必要依据.

圆竹的力学性能及影响因素研究

为了获得圆竹的主要力学性能及其影响因素,完成了6组共计51个试件的试验研究,获得了圆竹的抗压强度、环刚度以及抗弯强度等力学性能,研究了含水率、竹节和取材单元对上述力学性能的影响.结果表明:竹材顺纹抗压强度分别为弦向横纹和径向横纹抗压强度的2.7倍和4.0倍;竹节的紧箍作用有效提高了圆竹的环刚度,节部材较节间材提高90%;竹节对竹材的抗压强度具有一定的提高作用,节部材较节间材提高6.3%;含水率对圆竹抗压强度和抗弯强度有较大影响,但其影响趋势不同.圆竹的抗压强度随竹材含水率降低而增加,含水率降低40%时抗压强度提高约20%,而其抗弯强度随竹材含水率的降低而降低,在挠度相同的前提下,抗弯强度下降约20%.

刚竹秆褐腐病病原形态及分子鉴定

刚竹秆褐腐病在南京地区发生较普遍,影响竹林生长。其主要危害刚竹属的淡竹(Phyl-lostachys glauca)、黄槽刚竹(Ph.viridis f.houzeauana),其中以淡竹受害最为严重。笔者通过对刚竹秆褐腐病病组织分离培养、人工接种试验、分离菌形态学观察及采用通用引物ITS1/ITS4扩增,对扩增出的约559 bp的片段进行ITS序列分子鉴定,最终将在淡竹和黄槽刚竹等上发生的病原鉴定为木贼镰刀菌(Fusarium equiseti(Corda)Sacc.)。