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 indicator to support the determination of maturity of guadua culms besides the visual assessment of the culms.     

Relationships of culm surface area to other culm dimensions for bamboo, Phyllostachys pubescens

We determine the relationships of culm surface area to other culm dimensions for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houzeau de Lehaie. A total number of 150 sample culms were collected from a stand of P. pubescens in Mt. Toshima, Kumamoto Prefecture, western Japan. The culm surface area for each sample was calculated, and then the relationships of the culm surface area to basal area and product of diameter at breast height (dbh) and culm height were analyzed. The relationship between culm surface area and basal area could be described successfully by the power equation, whereas there was a linear relationship of culm surface area to product of dbh and height. Although the regression equations determined here would be useful in estimating culm surface area of P. pubescens, it is necessary to select an appropriate equation depending on the purpose and available time and labor.     

基于松香改性的圆竹视觉性能

为改善圆竹的表面视觉性能，利用天然松香在不同温度下浸渍处理圆竹，采用定量色差和光泽度测量法结合感性眼动追踪法，评价了不同温度下松香处理对圆竹表面视觉特性的影响；利用扫描电镜和傅里叶红外分析探讨了松香对竹材表面视觉特性影响的机理。结果表明，对松香适当的加热有利于其在圆竹表面形成连续的薄膜，提高圆竹表面光泽度，当温度为50 ℃时达到最大光泽度19.6，比对照组提高了122.7%。同时伴随着处理温度的升高，圆竹表面亮度逐渐降低，并且颜色从黄绿区间逐渐向红蓝区间转变；此外当温度高于60 ℃时，圆竹皮层受损脱落，在圆竹表面形成条纹，并且条纹的密度随着处理温度的增加而增加。眼动追踪实验和主观评价结果表明，高光泽度会产生不适感，纯色表面受到大众的喜爱，而条纹表面的圆竹会受到小众的喜欢。     

基于热消散技术的毛竹林蒸腾耗水估算

【目的】试验不同长度热消散探针(TDP)测量毛竹液流的可行性,分析年龄对立竹液流的影响,并据此对立竹液流进行尺度扩展,估算桂北毛竹林的蒸腾耗水,为区域毛竹林的生态水文效应研究和指导关键生态功能区植被结构调整提供依据。【方法】显微镜观察毛竹输水结构在竹壁上的径向分布。基于热消散方法,用5 mm和10 mm长度的TDP探针对1～2年生立竹和3龄以上立竹的基部液流进行连续测量,并同步测定环境因子。【结果】维管束在毛竹竹壁上不均匀分布,竹壁外侧维管束小而密,导管分化不完全,竹壁内侧维管束大而疏,导管分化完全,直径较大。10 mm TDP探针测得的液流密度显著高于5 mm探针,其平均液流密度是5 mm探针的4.03倍。在生长旺季的7月,基于10 mm TDP探针测量的1～2年生立竹正午液流密度显著高于3龄以上立竹,而在早上和傍晚二者基本相同。1～2年生立竹液流的平均日通量在测量生长季内均高于3龄以上立竹,二者的平均日液流通量分别为51.15和33.80 g·cm^-2 d^-1。以立竹年龄和基径作为液流尺度扩展依据估测的桂北毛竹林日蒸腾耗水量在观测生长季内为0.01～0.72 mm·d^-1,平均日蒸腾耗水量为0.31 mm·d^-1。【结论】10 mm长度的TDP探针较5 mm探针更适宜用于毛竹液流的测量。1～2年生立竹比3龄以上立竹具有更高的液流密度和日液流通量,因此年龄是毛竹液流由立竹到林分尺度扩展时除立竹直径外另一个必须要考虑的因素。     

Sampling procedure for density estimation of bamboo galls induced by <Emphasis Type="Italic">Aiolomorphus rhopaloides</Emphasis> (Hymenoptera: Eurytomidae) in a bamboo stand

 To establish a sampling procedure for estimating the density of bamboo galls induced by Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae) in a stand of bamboo Phyllostachys heterocycla (Carr. Mitf.) (Monocotyledoneae: Gramineae), 5–12 bamboo culms were cut at random in late March of each year during 1998–2001 just before gall-maker emergence. The number of galls on the branches of each bamboo culm was counted. The spatial patterns of the galls on the culms in the stand and on the branches within each culm were measured by Iwao's patchiness regression. Galls were distributed contagiously both on culms and on branches. Current bamboo culms that emerged the previous summer did not require sampling because no galls were observed on them. Except for this, there was no difference in gall density on young and old culms, suggesting that it is not necessary to distinguish them. There were few (<4%) galls above 6 m height during the 4 years. There was no significant difference in gall density up to 4 m and above 4 m, suggesting that branches up to 4 m can be sampled with confidence. Kuno's two-stage sampling method at different precision levels showed that the number of culms to be sampled varied with gall density. For example, at mean density m = 1.0 per branch when the number of sampled branches per culm is 10, a total of 24 culms is required to estimate gall number at a precision level of D = 0.2, where D is the ratio of standard error to mean. Received: July 10, 2002 / Accepted: November 25, 2002 Acknowledgments I thank Dr. K. Kamijo for insect identification. Thanks are also due to the members of the Laboratory of Forest Protection for their kind help with the fieldwork. This study was supported in part by a Grant-in-Aid for Scientific Research (No. 11460068) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.     

白夹竹生物学特性观察

经观察，白夹竹鞭梢生长期６－１１月，鞭分布在土壤上层１－１５ｃｍ。鞭年生长１ｍ左右。笋芽３－４月萌动，笋从５月初长出地面至５月底不再出笋，历时２８天左右，每公顷大年笋１００００个左右，上林率为２９．５４％，虫退笋率为４３．９８％，自然 笋率为２６．４８％，上林率，大年高于小年，初期，盛期出笋高于末期出笋。竹笋从出土到长成幼竹，历时６０天左右，竹笋高生长，一般夜晚稍大于白天，笋箨有吐水同象，１９８５     

过度生物干扰和火烧对梨竹林茎秆直径、密度及种子产出的影响

A study was conducted to investigate culms density and size, seed size and production rate in Melocanna baccifera stands disturbed by biotic pressure and fire. Results revealed that culms density, number and size of seeds produced in the bamboo stands were significantly affected by frequent fire and excessive biotic pressure （collection of young shoots for vegetables and mature culms）. The culm density and seed production rate decreased significantly in the stand subjected to excessive biotic pressure. An increasing exposure of culms to sun light was responsible for the above decrease. Seed production rate significantly increased in case of culms subjected to fire in comparison to the control. It indicated that fire stimulated the seed production in M. baccifera stand.     

毛竹茎秆组织速生的时空发育特征

为探索毛竹从发笋到竹秆形成的组织发育规律,对不同发育时期和部位的毛竹茎秆进行组织解剖分析并进行数量化分析。结果表明:竹秆的快速发育主要表现在节间的纵轴方向,节间发育由细胞分裂和细胞伸长控制。发育初期,在薄壁细胞和纤维细胞上可以看到大量的细胞核出现,此时细胞分裂占主导地位;随着组织发育,细胞核逐渐减少并消失,薄壁细胞和纤维细胞的长度显著增加,细胞伸长在发育中后期占主导地位。竹秆的发育、成熟和老化从基部首先启动,中部和顶部要顺次晚一些。基部的纤维组织最先出现木质化,此时茎秆的高度大约为6 m。竹秆的细胞伸长呈阶段性的波动,薄壁组织的细胞长度在快速伸长期偏离正态分布,在缓慢伸长期呈正态分布。     

Lignification in developing culms of bamboo <Emphasis Type="Italic">Sinobambusa tootsik</Emphasis>

Bamboos are among the largest woody grasses and grow very rapidly. Although lignin is a crucial factor for the utilization of bamboo biomass, the lignification mechanism of bamboo shoots is poorly understood. We studied lignification in the bamboo Sinobambusa tootsik during culm development. Elongation growth began in May and ended in late-June, when the lignin content was approximately half that in mature culms. Thioacidolysis analysis indicated that p-hydroxyphenyl units in lignin formed even at late stages of lignification. The syringyl/guaiacyl ratio varied during culm development. Various lignin precursors were detected in developing culms by liquid chromatography–mass spectrometry. The ferulic acid content decreased from May to June, indicating that ferulic acid was utilized in early stages of cell wall formation. Monolignol glucosides were detected at early stages of lignification, whereas the contents of monolignols, coniferaldehyde, sinapaldehyde, p-coumaric acid, and ferulic acid peaked at later stages of lignification. Therefore, lignin precursors may be supplied differentially during the lignification process. In August, the rate of lignification decreased, although the contents of various lignin precursors peaked, implying that the rate-limiting step in the cessation of lignification in bamboo is transport or polymerization of lignin precursors, rather than their biosynthesis.     

Variability in fibre and parenchyma cell walls of temperate and tropical bamboo culms of different ages

This study tries to clarify the conflicting results from previous studies on cell wall thickening in bamboo culms by applying light and transmission electron microscopy in combination with image analysis. It focused on both fibre and parenchyma wall thickness of both temperate (Phyllostachys spp.) and tropical (Gigantochloa levis and Dendrocalamus asper) bamboo species of different ages in the light of their suitability for the wood industry. The observations indicated a great heterogeneity in cell wall thickness and cell wall layering pattern of fibres within one culm. Nested design ANOVA’s revealed a rising trend in wall thickness of late maturing fibres and parenchyma cells during the first year but significant wall thickening during later years could not be demonstrated. The high variability within one culm and between culms of the same age from 1 year on is partly masking a clear increased cell wall thickening at higher age. Nevertheless, the highest mean values for fibre wall thickness were recorded in culms of 44 months old or older, suggesting that some kind of late cell wall maturing can take place within one culm.     

Changes in foliar nitrogen resorption of Phyllostachys edulis with culm development

Leaf nitrogen resorption is very important to Phyllostachys edulis development because the withdrawn nitrogen can help newly emerging and growing culms.However, few studies have focused on the ontogenetic changes in leaf nitrogen resorption of P. edulis. Here, we examined the variability in mature leaf nitrogen concentrations(Nm), nitrogen resorption efficiency(NRE) and proficiency(NRP or Ns) and leaf-level nitrogen use efficiency(NUE) of the current-, 3 rd-and 5 th-year culms in P.edulis stands under extensive management. Analyses of variance and correlation indicated that patterns of Nm,NRP, NRE and NUE were markedly affected by culm age and leaf nitrogen status. Nm, Nsand NRE were significant higher in younger(current-year) culms with 1-year lifespan leaves, while NUE was markedly higher in older(3 rd-or 5 th-year) culms with 2-year lifespan leaves. Significant linear correlations between Nmand NRP, NRE and NUE,Nmand NUE, Nsand NRE were found for each culm age,and Nmwas significantly positively correlated to NRE for all culms pooled. Higher proficiency in older culms led to higher NUE and lower NRE, these relationships can be modulated by Nm, which in turn, is restrained by leaf N availability and acquisition. Our results revealed that at the intraspecific level, P. edulis can adjust its leaf NRE, NRP,and leaf-level NUE in concert with culm development.Understanding nitrogen resorption characteristics and NUE of P. edulis can help decision-makers design appropriate deforestation strategies and achieve precise N fertilization for sustainable bamboo forest management.     

Derivation of two-way volume equation for bamboo, <Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>

We derive a two-way volume equation for estimating the apparent culm volume of one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. The volume equation was derived from the assumptions that (1) the relative culm form can be expressed by Kunze’s equation and (2) normal form-factors at two different relative heights are steady at constants independent of culm sizes. A total number of 200 sample culms were collected from a stand of P. pubescens in Mt. Toshima, Kumamoto Prefecture, western Japan, and were randomly bisected into two sets of data, i.e. modeling and test data. For the modeling data, normal form-factors at 0.6 and 0.9 in relative height were steady at 0.908 and 0.448, respectively. The coefficients of the volume equation were determined based on these steady values of the normal form-factors. For the test data, the apparent culm volume was estimated from diameter at breast height and culm height with the determined volume equation. The mean error and root mean square error of the estimated culm volume were, respectively, 8.120 × 10⁻⁵ and 3.291 × 10⁻³ m³, and there was no significant difference between estimated and actual volume. In conclusion, the two-way volume equation presented here appears to be convenient for predicting the apparent culm volume for P. pubescens.     

Length curves and volume functions for guadua bamboo (Guadua angustifolia Kunth) for the coffee region of Colombia

Three models for the prediction of bamboo culm length and two for culm volume were fitted from data of 303 guadua bamboo (Guadua angustifolia Kunth) culms. Data are from 101 temporary inventory plots systematically distributed over the coffee region of Colombia (inventory area about 1,029,525 ha). Linear and non-linear regression models were used, and the precision of the models was evaluated by cross-validation. The models were compared by studying the adjusted coefficient of determination, the bias, mean square error and Akaike’s information criterion and by the F-test that compares predicted and observed values. For culm length, the best fit showed models that included predictor variables related to stand characteristics such as quadratic mean diameter and number of culms per ha. For culm volume prediction, the inclusion of culm length improved the model significantly. For the simple form factor model, precision of prediction was least. The models developed are useful in facilitating the estimation of stand characteristics that are relevant for the silvicultural management of Guadua stands and also for the assessment of their environmental services (such as carbon sequestration).     

原态竹材湿热应变响应

【目的】分析原态竹材对环境温度和相对湿度的应变响应,为原态竹材的尺寸稳定性和环境适用性研究提供基础依据。【方法】以我国6个城市的年均温度和相对湿度为基础数据,通过湿热图谱研究原态竹材的湿热应变行为,采用静态应变仪采集直径相似(96.52 mm±1.46 mm)但长度不同(500、400、300和200 mm)原态竹材依次经历6个阶段温湿度变化(5 ℃、66%;13 ℃、50%;20 ℃、70%;20 ℃、80%;30 ℃、80%;9 ℃、36%)过程中端部和中部的周向应变以及原态竹材的轴向应变数据,分析讨论温度、湿度和长度对原态竹材应变响应行为的影响。【结果】初始状态应变值设定为零,竹材水分蒸发收缩时应变为负,吸湿膨胀时应变为正,当温湿度骤然下降时,试样端部和中部膨胀应变急剧减小甚至开始收缩。竹材的周向应变为-500~3 000 με,轴向应变为-50~225 με。原态竹材端部周向应变较敏感,中部周向应变出现滞后现象。长度为500和400 mm试样端部和中部的最大应变差较大,相比300和200 mm试样端部应变差差异显著;较短试样端部和中部的应变差从正值缩小为零后变为负值,端部和中部应变行为出现此消彼长现象。【结论】原态竹材能够对温湿度变化做出即时响应,温度、湿度和长度对原态竹材的应变响应具有明显影响,温度的影响主要依赖湿度导致竹材含水率变化来体现。周向应变与轴向应变行为相似,但明显大于轴向应变,端部对温湿度的响应更为敏感,中部响应有滞后现象,长度越长的竹材内部干缩或湿胀应力越不均衡。温湿度变化引起原态竹材内应力不均衡是原态竹材应变不均甚至开裂的主要原因。     

The effect of high-temperature drying on the antisplitting properties of makino bamboo culm (Phyllostachys makinoi Hay.)

Summary The anatomical structure of bamboo culm is governed by the number, arrangement, shape and size of the vascular bundles. The vascular bundles at the peripheral zone of the culm are small and numerous, while those of the inner part are larger in size and smaller in number. No radial cell elements are present in the culm. Due to these peculiar structures, bamboo culms are susceptible to splitting during seasoning.This problem has been overcome by applying a high-temperature drying technique.When makino bamboo (Phyllostachys makinoi Hay.) culms were dried under elevated temperatures (from 60 °C up to 120 °C), no splits occurred on the culm surface. This phenomenon is explained by chemical composition analysis, mechanical properties associated with physical changes, scanning electron microscope and x-ray diffractometer observations.This paper was presented as a poster at the XIXth IUFRO World Congress in Montreal, Canada, August 1990. The author wishes to express his great appreciation to Dr. F. Tanaka of Wood Research Institute, Kyoto Univ., for the crystallinity determination. Thanks are given to the Government Industrial Research Institute, Osaka, Japan, for providing the x-ray diffractometer, and the National Science Council of Republic of China for supporting a 3-month leave at Wood Research Institute, Kyoto University     

High nitrate reductase activity in sprouts of Phyllostachys pubescens

We investigated the distribution of nitrate reductase activity (NRA) among leaves, roots, culms, twigs, sprouts, culm sheaths, and new leaves of Phyllostachys pubescens Mazel in May, when many sprouts emerge above ground and new leaves of adult culms expand. We found that the NRA differed among parts, and that sprouts showed high NRA. These results indicate that different tissues of P. pubescens vary in nitrate reduction, and sprouts possess high nitrate reduction capacity. We also found that culm sheaths showed high NRA, indicating that they have a high potential for nitrate reduction, even though they are shed in the way of sprout growth.     

气象因素对毛竹秆形生长变异的影响

在我国毛竹中心产区的调查分析结果表明 :毛竹的秆形生长同气象因素关系密切 ,在毛竹生长期内不同的具体生理过程 ,各种气象因子的影响程度不同 ,其中的某一或几个因子为主导性或限制性因子并同时综合作用于毛竹的生长发育。但是出笋成竹期和孕笋期的气候因子对毛竹的秆形生长量起决定作用 ,而其中降水因素的作用大于温度因素。此外 ,无论从不同产区 ,还是同一产区内不同地点的毛竹秆形生长变异同气象因子之间相关分析 ,均可知生长地有利的基本温、湿条件(常年的温、湿度条件 )是毛竹生长的前提条件。     

Population status and regeneration of a tropical clumping bamboo <Emphasis Type="Italic">Schizostachyum dullooa</Emphasis> under two management regimes

Schizostachyum dullooa (Gamble) Majumder ‘dolu bamboo’ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management (PPRM) and common property resource management (CPRM) regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year (83%), one-year (16%) and two-year (1%) old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.     

巴山木竹发笋生长规律的观察

本文对巴山木竹(Bashania fargesii)作了发笋规律,成竹规律和高生长规律的研究。发笋规律的研究包括五个方面:1.发笋季节;2.发笋部位;3.鞭、母竹年龄和发笋;4.鞭系深度和发笋;5.立竹数量与发笋。其成竹及高生长规律也分别作了简要介绍。     

白水江自然保护区龙头竹种群年龄结构的初步研究

生物种群的数量具有相对稳定性。国内外许多植物生态学家对多种竹子进行了很多有成效的研究。但对大熊猫所食的龙头竹研究甚少,特别是对其立竹年龄结构规律的研究还是一项空白。鉴于发现大熊猫活动区主食龙头竹有开花现象,为了掌握其种群动态,本文依据笔者1988年的调查资料,以甘肃南部白水江自然保护区内大熊猫的主食龙头竹林为对象,讨论了龙头竹种群立竹年龄结构规律。