Culm form analysis for bamboo, Phyllostachys pubescens

We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the me- chanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens.

Factors affecting soil organic carbon in a Phyllostachys edulis forest

Phyllostachys edulis plays an important role in maintaining carbon cycling.We examined the effects of soil properties on organic carbon content in a P.edulis forest on Dagang Mountain,Jiangxi Province,China.Based on correlation and stepwise multiple regression analyses,the effects of seven soil factors on organic carbon and their sensitivities to change were studied using path and sensitivity analyses.The results revealed differences in the interconnections and intensities of soil factors on organic carbon.Soil porosity,field capacity,and ammonium nitrogen levels were the main factors affecting organic carbon in the ecosystem.Soil porosity had a strong direct effect on organic carbon content and a strong indirect effect through field capacity.Field capacity and ammonium nitrogen levels mainly affected organic carbon directly.Field capacity,soil porosity,and ammonium nitrogen content,as well as bulk density,b-glucosidase activity,and invertase activity,were sensitive factors.Polyphenol oxidase activity was insensitive.Our study provides a theoretical basis for understanding the effects of soil factors on organic carbon,which can be utilised to improve P.edulis forest management strategies and promote carbon sequestration capacities.

Modeling of the height–diameter relationship using an allometric equation model:a case study of stands of Phyllostachys edulis

Understanding the relationship between tree height （H） and diameter at breast height （D） is vital to forest design, monitoring and biomass estimation. We developed an allometric equation model and tested its applicability for unevenly aged stands of moso bamboo forest at a regional scale. Field data were collected for 21 plots. Based on these data, we identified two strong power relationships： a corre- lation between the mean bamboo height （Hm） and the upper mean H （Hu）, and a correlation between the mean D （Din） and the upper mean D （Du）. Simulation results derived from the aUometric equation model were in good agreement with observed culms derived from the field data for the 21 stands, with a root-mean-square error and relative root-mean-square error of 1.40 m and 13.41%, respectively. These results demonstrate that the allometric equation model had a strong predictive power in the unevenly aged stands at a regional scale. In addition, the estimated average height-diameter （H-D） model for South Anhui Province was used to predict H for the same type of bamboo in Hunan Province based on the measured D, and the results were highly similar. The allometric equation model has multiple uses at the regional scale, including the evaluation of the variation in the H- D relationship among regions. The model describes the average H-D relationship without considering the effects caused by variation in site conditions, tree density and other factors.

Dynamic Changes of Chemical and Mechanical Properties of Moso Bamboo (Phyllostachys edulis) Culms under Different Storage Conditions

The durability of bamboo based on its chemical and mechanical properties is a crucial consideration for the wood-based industry due to its vulnerability to insects and microorganisms.We investigated the dynamic changes of chemical and mechanical properties of Phyllostachys edulis under air-dry and water storage conditions for 3,6 and 12 months respectively.The chemical properties of P.edulis bamboo culms varied with culm age but insignificantly with culm height.The mechanical properties of P.edulis culms showed an increasing trend with culm age.Water storage condition decreased the ash,SiO2 and lignin content,but increased the ethanol-benzene extracts.It also created an anaerobic environment for bamboo culms in which only anaerobic respiration was possible contributing to reducing the content of soluble sugar and starch,thereby beneficial for decreasing the damage from insects and microorganisms.Moreover,the water storage conditions could maintain culm mechanical performance better.Therefore,the indigenous practice of local people to store bamboo culms in ponds has good science behind it and water storage practices of bamboo culms was recommended.

Estimation of culm volume reduction factors in five bamboo species(Phyllostachys spp.)

The hollow cylindrical culm is one of the most remarkable morphological characters of most bamboo species.In relation to its hollow structure,there are two different attributes of the culm volume in bamboo:the apparent culm volume(va:the total culm volume including the hollow portion)and the woody culm volume(vw:the volume of the woody walls of the culm).The ratio of vw to va is defined as the reduction factor for culm volume(fv).The quantity fv is useful to quantify the biomass resources of bamboo culms as well as to evaluate the carbon stock of bamboo forests.However,the direct measurement of fv requires destructive sampling,which consumes time and labor.Hence,an alternative method for obtaining fv is desired.In this study,we examined fv in five species of the genus Phyllostachys and proposed alternative methods to estimate fv.Our data showed that fv varied by species,some of which exhibited a dependency of fv on culm sizes.These findings indicate that the intraspecific and interspecific variation in fv should be considered carefully when converting va into vw by fv.Based on our results,we propose here six approaches for predicting fv and we discuss their advantages and disadvantages.Our results are intended to facilitate evaluation of the carbon sequestration capacity of bamboo forests and the commercial utilization of bamboo culms.

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.

Physiological changes of leaves in response to cold in Phyllostachys propinqua

There are no previous records about planting bamboo in Changli, Hebei Province, north China. Since they were introduced in 2004, the propinquity bamboo （Phyllostachys propinqua McClure） has demonstrated good adaptability to the cold climate in Changli. The overwintering status of the bamboo and some of its physiological changes after the winter have been studied to ascer- tain the adaptability of the bamboo to the cold weather in Changli and to establish a firm basis for growing the plants in larger areas in northern China. The bamboo lived through the winter without any protection. The leaves of windward bamboos growing at various intervals have been studied for their viability and health after the winter. The changes in some physiological indices of the leaves were measured in the following spring. Results showed that the bamboo is partly green even at a temperature as low as -22.3℃ in Changli. During the winter, some leaves died and some partly died. Leaves are light in color and turn gradually to a dark green when the temperature increases in the following spring. As new leaves develop, the contents of chlorophyll and water and the ratio of fi＇ee and bound water in the old leaves increase as does transpiration. At the same time the contents of free amino acid, proline, soluble sugar, malondialdehede （MDA）, permeability of the membrane, superoxide dismutase （SOD） and peroxidase （POD） activities de- crease. The direction of these physiological indices changes when the new leaves begin to sprout. The old leaves reduce their rate of photosynthesis, their blade functions decline gradually and the leaves fall off towards the middle of June. The cold wind affects the survival of bamboo leaves in winter, but has little effect on new leaves growing at the start of the following year. The results indicate that the propinquity bamboo can survive the winter in Changli quite well.

A <i>β</i>-Glucosidase Activity Potentially Involved in Cell Division and Wall Development of <i>Phyllostachys</i>Bamboo Suspension Cells

We propose a novel Madake (Phyllostachys bambusoides) bamboo suspension culture model for investigation of key enzyme(s) activity involved in growth/differentiation. Sedimented Cell Volume (SCV) and fresh weight (FW) of the suspension cultured cells reached 34% (v/v) and 8.7 g in 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D)-containing medium while only 7% (v/v) SCV and 1.9 g FW of the cells in 10 μM gibberellic acid (GA3)-containing medium in 14 days. Proportion of mitotically active cells (S to G2/M phases) at a log phase was identified as 29.5% in the former cells with tiny cytoplasmic features while 5.4% in the latter cells with elongation, wall thickening, and lignification by using flow cytometry and laser scanning microscopic analysis. The total β-glucosidase (BGL) activity under the 2,4-D condition increased from 4.8 U in day 2 to 26.2 U in day 14 (ca. 5.5-fold) while a slight reduction, from 4.4 U in day 2 to 2.1 U in day 14 (ca. 0.5-fold), occurred when cell division was suppressed under the GA3 condition. Ratio of the BGL activity of the soluble fractions to the membrane-associated fractions varied depending of the culture condition. The ratio was stable (2 to 8) during the culture period under the 2,4-D condition. Interestingly, the activity of the soluble enzyme fractions increased up to ca. 65% under the GA3 condition in inverse proportion to the membrane-associated enzymes. All together, it was strongly suggested that the detected specificity/variability of BGL activity is potentially involved in cell division and lignification in Madake bamboo cells.

Diurnal Variation of Atmospheric Aerosol Particles in the Phyllostachys heterocycla Forest in Spring

Taking the Phyllostachys heterocycla forest in Qishan National Forest Park of Fuzhou for example,this study observed the diurnal variation of atmospheric aerosol particles in the forest in the growing season.The results showed that:① The diurnal variation curves of the particle concentration of the forest and the forest edge had “two peaks and two troughs”,but the peaks and troughs of the forest edge were advanced or delayed.The concentrations of the particles in the forest and at the forest edge had two peaks at 11:00–13:00 and 17:00–19:00 and two troughs at 7:00–9:00 and 15:00–17:00.② For the forest and the forest edge,the diurnal variation trends of the particles of different particle sizes were generally similar,except that the peaks and troughs of fine particles were slightly earlier or lagging than that of coarse particles.③ The concentrations of the particles were positively correlated with temperature,humidity and light,and negatively correlated with wind speed,and the concentrations of the particles at the forest edge were significantly negatively correlated with wind speed.

Human Comfort of the Phyllostachys heterocycla Forest in Summer

This study analyzed the microclimate factors and human comfort index inside and outside the Phyl ostachys heterocycla forest of Qishan Natiional Forest Park in summer,and compared them with those of the city square.The results showed that:(1)In terms of the average daily temperature,the inner and outer forests and the city square ranked as follows:city square>outer forest>inner forest.The temperature of the inner forest was 5.41–10.31°C lower than that of the city square,and the temperature of the outer forest was 4.41–9.51°C lower than that of the city square.(2)In terms of the average daily relative humidity,the inner and outer forests and the city square ranked as follows:city square<outer forest<inner forest.Compared with the city sqaure,the inner forest had an increase of 8.21–31.51%in relative humidity,and the outer forest had an increase of 8.11–26.16%in relative humidity.(3)In terms of the average daily wind speed,the inner and outer forests and the city square ranked as follows:city square>outer forest>inner forest.The daily average value of the city square was 42%and 37%higher than that of the inner and outer forests,and the daily average value of the outer forest was 21%higher than that of the inner forest.(4)In terms of the daily average illumination intensity,the inner and outer forests and the square ranked as follows:city square>outer forest>inner forest.The daily average value of the city square was 97.38%and 74.33%higher than that of the inner and outer forests,and the daily average value of the outer forest was 89.78%higher than that of the inner forest.

Thermal Decomposition of Bamboo Phyllostachys Edulis Pretreated with Ionic Liquids-Water Mixtures

The ionic liquid (IL)-water mixture pretreated bamboo (Phyllostachys edulis) samples were applied in the research of thermal decomposition. [BMIM]Cl (1-Butyl-3-methylimidazolium chloride)- water and [BMIM]BF4 (1-Butyl-3-methylimidazolium tetrafluoroborate)-water were used in pretreatment process. Compositions of the untreated bamboo and pretreated bamboo were compared. The results of X-ray diffraction analysis (XRD) were analyzed to explain the effect of ILs mixture on cellulose crystalline structure. The pretreated cellulose with [BMIM]Cl&#45 water mixture was tend to produce the more gaseous products, which were associated with the decomposition rate. The behavior of more CO and CH4 gaseous products and less tar in the thermal decomposition products could be attributed to ILs-water mixture pretreatment process. The potential and some problems of ILs-water mixture pretreatment method applied in thermal chemical conversion methods were also discussed.

Effects of Canopy Closure on Photosynthetic Characteristics of Ilex latifolia Thunb.in Phyllostachys pubescens Forests

Plantation under the forest is a good way of agroforestry,but the canopy closure has a great influence on understory herbs’growth.In the study,different canopy closures of Phyllostachys pubescens forests were set up to explore its influence on the growth of Ilex latifolia Thunb.The photosynthetic characteristics of Ilex latifolia leaves under different canopy closures were determined by Li-6400 portable photosynthetic system.The results showed that the net photosynthetic rate curve of Ilex latifolia leaves of T1(canopy closure of 0.56)was bimodal with an obvious"midday depression"phenomenon,while the net photosynthetic rate curves of T2(canopy closure of 0.72)and T3(canopy closure of 0.86)were unimodal.The results of light response curve showed that the photosynthetically active radiation and transpiration rate reduced with the increasing of canopy closures.The photosynthetically active radiation,transpiration rate,stomatal conductance,and net photosynthetic rate of Ilex latifolia leaves of T2 were higher than those of T3.Although the net photosynthetic rate of T2 was lower than that of T1,it had no obvious photo-inhibition which affected plant growth.Overall,the canopy closure of 0.72 was more suitable for the growth of Ilex latifolia.The herb plantation in the bamboo forest should be considered with the canopy closure for a better growth.

Multi-omics of Circular RNAs and Their Responses to Hormones in Moso Bamboo(Phyllostachys edulis)

Circular RNAs(circRNAs)are endogenous non-coding RNAs with covalently closed structures,which have important functions in plants.However,their biogenesis,degradation,and function upon treatment with gibberellins(GAs)and auxins(1-naphthaleneacetic acid,NAA)remain unknown.Here,we systematically identified and characterized the expression patterns,evolutionary conservation,genomic features,and internal structures of circRNAs using RNase R-treated libraries from moso bamboo(Phyllostachys edulis)seedlings.Moreover,we investigated the biogenesis of circRNAs dependent on both cis-and trans-regulation.We explored the function of circRNAs,including their roles in regulating microRNA(miRNA)-related genes and modulating the alternative splicing of their linear counterparts.Importantly,we developed a customized degradome sequencing approach to detect miRNA-mediated cleavage of circRNAs.Finally,we presented a comprehensive view of the participation of circRNAs in the regulation of hormone metabolism upon treatment of bamboo seedlings with GA and NAA.Collectively,our study provides insights into the biogenesis,function,and miRNA-mediated degradation of circRNAs in moso bamboo.

毛竹(Phyllostachys edulis)PheGT8和PheGT16基因的克隆与表达分析

三螺旋转录因子在植物响应非生物胁迫过程中具有潜在的作用。本研究通过对毛竹(Phyllostachys edulis)中2个三螺旋转录因子基因进行生物信息学分析,并对其在不同胁迫条件下的表达水平进行研究,初步解析毛竹三螺旋转录因子基因的功能。本研究克隆得到2个毛竹三螺旋转录因子基因PheGT8和PheGT16,发现这两个基因在低温、干旱、盐胁迫以及脱落酸(abscisic acid,ABA)、吲哚-3-乙酸(indole-3-acetic acid,IAA)、水杨酸(salicylic acid,SA)和茉莉酸甲酯(methyl jasmonate,MeJA)处理时,表达均呈现了不同程度的上调或下调,表明这两个基因参与了毛竹应对非生物胁迫的应答过程,具有潜在的调控作用。

Study on Litter Water Interception Capacity of Phyllostachys edulis Plantations with Different Densities

The litter amount and the water holding characteristic parameters,such as the maximum water holding capacity and rate,the water absorption rate and the modified interception amount of Phyllostachys edulis plantations with four densities were studied in Huangshan district.The results are as follows:The total amount,thickness and natural water content of litters under all the four stands tested were different.The total litter amount in different stands ranged between 3.98 t·ha-1 to 6.00 t·ha-1, which in the stand with the density of 3 000 stems·ha-1 was the most.The ratio of maximum water-holding capacity of litter in various stands ranged from 317.09%to 347.58%.The maximum water holding capacity of litter in the stand with the density of 3 000 stems·ha-1 was 20.70 t·ha-1. By analyzing,the relationship between the water holding capacity of litter and the immersion time followed the equation of:S = alnt + b（a is the coefficient;b is the constant term）.The relationship between the water absorption speed of the litter and the immerse time followed the equation of: V = ctd（c is the coefficient;d is the exponential term）.The litter water capacity increased rapidly within the first four hours,and then increased slowly.The results also showed that the hydrological character of litter was positively related to density in Ph.Edulis forest.Therefore, it is important to choose appropriate density for enhancing the eco-hydrological benefits of litter layer in Ph.edulis forest.

Visualization of Cellulose Microfibrils of Phyllostachys pubescens Fibers with Atomic Force Microscope

Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness of approximately 30 μm, which was used to investigate the arrangement of CMF in the inner wall of cell cavity of bamboo fibers. The results indicated that the CMF are randomly oriented in the primary wall while in the inner wall of cell cavity they are nearly vertical to the long axis of fibers , which is similar to the arrangement of CMF in the corresponding layer of wood fibers. Meanwhile, the highly oriented arrangement of CMF is also observed in a certain layer of bamboo fibers, though it is incapable of determining which layer it is in this study. The pilot investigation demonstrates that AFM is a powerful tool for the high-resolution observation of CMF in bamboo fibers, meanwhile it has the advantages of simple procedure of sample preparation and easy operation compared to the traditional transmission electron microscopy.

不同劈草时间毛竹林生产力及土壤变化特征

2008-09在福建洋口国有林场,应用野外取样调查及实验室分析相结合的方法对未劈草(Ⅰ)、劈草10a(Ⅱ)和劈草30a(Ⅲ)的毛竹林生产力及土壤变化特征进行研究。结果表明:劈草可以显著提高毛竹林的生产力,但是随着劈草时间的延长毛竹林增产效果降低。三种林分生产力排列顺序为Ⅱ>Ⅲ>Ⅰ,分别为44199.57±395.40、43508.04±346.12和35691.31±394.68kg/(hm2.a)。劈草时间不同,不同器官的生产力分配也不同,地下部分生产力所占比例的排列顺序为Ⅱ>Ⅲ>Ⅰ,分别为24.87%、24.72%和24.31%。劈草经营有降低毛竹林地上部分生产力,增加地下部分生产力的趋势。土壤综合性质随着劈草时间的延长呈降低趋势,三种林分平均得分的排列顺序为Ⅰ>Ⅲ>Ⅱ,分别为0.6390、0.4320和0.3558。

毛竹纳米纤丝化纤维素球形气凝胶的制备和表征

以毛竹(Phyllostachys heterocycla cv.Pubescens)为原料,采用落球法制备纳米纤丝化纤维素(NFC)球形水凝胶,溶剂置换和超临界CO2干燥后得到了NFC球形气凝胶。通过透射电子显微镜(TEM)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)和BET对NFC球形气凝胶的微观形貌、化学态、结晶结构和孔隙结构进行表征分析。研究结果表明,NFC水凝胶和气凝胶均为球形,其化学组成和结晶结构均与天然纤维素一致,NFC气凝胶的骨架通过丝状纳米纤丝化纤维素缠绕和聚集形成三维网络结构,NFC气凝胶具有较高的比表面积和孔隙体积,分别为173 m2/g和0.62 cm3/g。

刚竹属化学成分及其抗肝损伤成分研究

刚竹属药用植物资源广泛,富含黄酮及其苷类、二萜酸类、木脂素类、生物碱类、醌类、糖类、挥发性成分、酚酸及衍生物类等成分。在长期寻找新的治疗肝损伤有效药物方面,目前国内外有比较多的研究,主要是一些中药及其多糖、黄酮类成分。文中综述了刚竹属中竹笋、竹叶和竹茹等防治肝损伤植物的研究进展,这为探明刚竹属药用植物防治肝损伤作用及其机理和深入研究开发效果较佳的防治肝损伤新型药物提供一定的科学依据。

毛竹EMF2类基因原核表达条件优化

在对毛竹EMF2基因功能研究的过程中,需要制备其抗体用于蛋白表达的检测。由于PheEMF2原核表达量低,纯化到的蛋白量不利于抗体制备,所以本研究用正交设计的方法对PheEMF2原核表达诱导条件进行优化,提高其原核蛋白表达量。根据L25(56)正交设计表设计诱导时间、诱导温度、IPTG终浓度、菌液OD值四因素五水平的融合蛋白表达诱导条件。用凝胶图像光密度分析系统分析各诱导条件下融合蛋白的表达量,发现菌液OD值和诱导温度对蛋白表达量有显著影响,而IPTG终浓度和诱导时间对蛋白表达量影响不显著。根据正交设计的效应曲线和方差分析结果,选择在菌株生长值OD600为1.1时,加入IPTG至终浓度1.0mmol/L,放入25℃摇床中振荡8 h诱导融合蛋白表达,融合蛋白的表达量约提升了10倍,占细菌总蛋白量的21.4%。