微晶和芦苇浆纳米纤维素的粒度分布分析

在一定工艺条件下,硫酸分别水解微晶纤维素和芦苇浆制备纳米纤维素,采用激光粒度分析法分别分析了微晶和芦苇浆纳米纤维素的粒度分布,结果表明以微晶纤维素为原料,在控制制备工艺条件下可以制备出三维尺度相差不大的纳米纤维素,Z均粒径为163.8 nm。芦苇浆纳米纤维素为非球形颗粒,且不同方向的尺寸相差较大,Z均粒径为942.0 nm。     

Arundo donax L. reed: new perspectives for pulping and bleaching. 5. Ozone-based TCF bleaching of organosolv pulps

Three selected alkali-based organosolv pulps (alkali-sulfite-anthraquinone-methanol (ASAM), alkali-anthraquinone-methanol (organocell) and ethanol-soda) from agrofibre crop giant reed (Arundo donax L.) were bleached by an ozone-based TCF (totally chlorine- free) bleaching sequence AZE(R)QP (where A is an acidic pulp pre-treatment, Z is an ozone stage, (E(R)) is an alkaline extraction in the presence of reducing agent, Q is a pulp chelating, P is a hydrogen peroxide stage) without oxygen pre-bleaching, and compared with a conventional kraft pulp used as a reference. The different response on bleaching conditions within each bleaching stage was noted for all tested pulps. The pulp bleachability, in terms of brightness improvement or lignin removal per unit of applied chemicals, was found higher for the organocell pulp. The ASAM and ethanol-soda pulps showed the highest bleaching selectivity, expressed by viscosity loss per unit of lignin removed or brightness improved. The overall bleaching results of organosolv pulps were superior to kraft.     

Technology and economics of ethanol production from fodder beets via solid-phase fermentation

Summary Operating conditions for our semi-continuous, solid-phase fermentation system were optimized for conversion of fodder beets to fuel ethanol and distiller's wet feed (DWF). This information was then used to estimate operating parameters achievable in a commercial plant, and likely baseline production costs of such a plant. Initial acidification of pulp to pH 2.9–3.2 was effective in controlling bacterial contamination. The maximum operating capacity of the fermentor was approximately 92%, with 75% used for commercial application. A fermentation time of 24 h was sufficient to completely ferment the beet pulp to 8–9% (v/v) ethanol. Based on these parameters, a fodder beet cost of $19.25/metric ton ($17.50/ton), other operating and capital costs, and a PF credit of $0.14/L ($0.53/gal), ethanol production costs were estimated to be $0.49/L ($1.87/gal).     

Investigation of a traditional reed economy (<Emphasis Type="Italic">Phragmites australis</Emphasis>) under threat: pulp and paper market,values and Netchain at Wuliangsuhai Lake,Inner Mongolia,China

Common Reed (Phragmites australis) is a wetland plant which is distributed worldwide, has a high biomass production, and provides important ecosystem services. In many developing and emerging countries it is an easily available and cheap raw material for diverse utilization, which may contribute significantly to employment and income generation for the local population. This case study investigates the reed utilization for pulp and paper production at the eutrophic Wuliangsuhai Lake, Inner Mongolia, China. We analysed the fluxes of materials and money along the supply chain (reed harvesting, processing and supply to final users, i.e. paper mills) as well as the division of work and costs at each production layer (network), based on the Netchain theory. The results make evident the importance of the paper industry and reed harvesting for local livelihood. They further reveal that the reed economy at Wuliangsuhai Lake is threatened by rising environmental standards for paper mills, change of market conditions and dependency on only two customers. Increasing revenues by finding new consumers or/and products, come to long-term contracts and improving harvesting efficiency are presented as ways to convert these threats into new opportunities.     

Arundo donax L. reed: new perspectives for pulping and bleaching. Part 4. Peroxide bleaching of organosolv pulps

A comparative study on TCF (totally chlorine-free) bleachability of organosolv pulps from the annual fibre crop Arundo donax L. (giant reed) was carried out using a simple three-stage peroxide bleaching sequence without oxygen pre-bleaching. ASAM (alkali-sulfite-anthraquinone-methanol), Organocell (alkali-anthraquinone-methanol) and ethanol-soda organosolv pulps were bleached and compared with kraft pulp, as a reference. The final brightness of 76-78% ISO was attained for all tested pulps. The chemical charge required to reach this level of brightness varied for different pulps (despite the equal initial content of the residual lignin) and directly related to starting brightness values. No direct correlation between brightness improvement and lignin removal during bleaching was found, indicating the influence of the specific pulp properties introduced by pulping process on bleaching chemistry. The general higher bleaching response of organosolv pulps from A. donax was noted in comparison with kraft.     

四种生态型芦苇叶片结构的研究

采用光学显微镜和电子显微镜对４种生态型芦苇（ＰｈｒａｇｍｉｔｅｓｃｏｍｍｕｎｉｓＴｒｉｎ．）叶解剖结构及叶脉维管束鞘细胞超微结构进行了观察研究。结果表明,沼泽芦苇维管束鞘细胞内含物较少,维管束鞘细胞叶绿体呈近圆形,超微结构与典型Ｃ３植物小麦鞘细胞的相似,基粒发育退化,不含淀粉粒;沙丘芦苇鞘细胞内含物较多,鞘细胞叶绿体呈近椭圆形,超微结构与典型Ｃ４植物玉米的相似,具有不发达的基粒;重度盐化草甸芦苇鞘细胞内含物则较沼泽芦苇多,而较沙丘芦苇少,鞘细胞叶绿体形态、超微结构与沙丘芦苇相似;轻度盐化草甸芦苇鞘细胞内含物与沙丘芦苇相似,但是,其鞘细胞含有与沼泽芦苇鞘细胞内叶绿体形态相似的近圆形以及与沙丘芦苇和重度盐化草甸芦苇鞘细胞内形态相似的近椭圆形两种形态的叶绿体。表明生长在同一地区不同环境中的４种生态型芦苇的光合结构发生了深刻的变异,表现出从Ｃ３向Ｃ４进化的明显趋势。     

四种生态型芦苇叶片结构的研究

The leaf anatomy and uhrastructure of the vascular bundle sheath cells of four ecotypes of reed (Phragmites communis Trin. ) were observed with light and electron microscope. The four ecotypes were the swamp reed, dune reed, heavy salt meadow reed and the light salt meadow reed. It was shown that the intracellular content of the vascular bundle sheath cells of the swamp reed was lower than that of the dune reed; that of the heavy salt meadow reed was between that of the former two reeds and that of the light salt meadow reed and that of the light salt meadow reed was similar to the dune reed. The chloroplasts in the swamp reed were round-shaped with poorly developed grana. Starch grains were not visualized. The uhrastructure of their chloroplasts were similar to those in the typical C3 plants as wheat. By contrast, the chloroplasts in the vascular bundle cells of the dune reed were elliptical with their structure similar to that of the typical C4 plants as maize. These chloroplasts contained some poorly developed grana thykloid. The chloroplasts of the vascular bundle sheath cells in the heavy salt meadow reed were similar to those seen in the dune reed, however, those in the light salt meadow reed appeared to be beth round .and elliptical in shape. The above results suggested a great habitat variation did occur among the four ecotypes of reed in which these exists an obvious evolutional trend from C3 to C4 plants.     

不同生态型芦苇Rubisco免疫学特性差异

以河西走廊荒漠地区不同生态型芦苇为研究材料,提取并纯化得Rubisco蛋白,经SDS-PAGE凝胶电泳将Rubisco大、小亚基分离,用Rubisco全酶蛋白及其大、小亚基分别注射昆明系雄性小白鼠制备抗体,经Western-blotting鉴定结果表明:(1)水芦Rubisco全酶抗体可与水芦、沙芦及菠菜Rubisco大亚基发生反应,而与小亚基均未见显色反应,且水芦显色最深,沙芦略浅,菠菜最浅;(2)水芦、沙芦Rubisco大亚基抗体可与水芦、沙芦、菠菜大亚基发生抗原交叉反应,且均不与小亚基发生反应,并且其与菠菜Rubisco大亚基的反应程度明显低于水芦和沙芦;(3)用与Rubisco大亚基抗体同样的制备方法,均未检测到水芦、沙芦Rubisco小亚基抗体的产生;(4)菠菜Rubisco全酶抗体可与菠菜、水芦、沙芦、水稻Rubisco大亚基均发生抗原交叉反应,但仅与其自身小亚基反应,且与菠菜Rubisco大亚基显色反应最深,水稻略浅,沙芦、水芦稍有反应.由此说明,水芦、沙芦Rubisco全酶蛋白及其大亚基免疫学特性差异较小,而与双子叶植物菠菜相比差异较大;水芦、沙芦Rubisco蛋白免疫化学决定簇的差异主要决定于小亚基上,且其小亚基不具有抗原活性或抗原活性较弱.     

Management of reedbeds: mosaic reed cutting does not affect prey abundance and nest predation rate of reed passerine birds

Reed passerine birds are strict habitat specialists inhabiting reedbed habitats. In Europe, many of these species are threatened due to loss and degradation of natural reedbeds. Another important factor that can negatively affect the abundance of reed passerines is commercial reed harvesting. Previous studies have shown negative impacts of large-scale winter reed cutting on passerine breeding assemblages and arthropod communities. The effect of reed cutting on a small scale, however, has not been studied experimentally to date. The aim of this study was to investigate whether and how small-scale, mosaic reed cutting influences prey abundance and nest predation rate of reed passerines. In June, after the reed had reached maturity, we conducted nest predation experiments with artificial nests and arthropod sampling using pan traps in cut reed patches, adjacent uncut reed patches and unmanaged reedbed. We found no differences in the risk of egg predation between three types of reedbeds. In contrast, the abundance of arthropods in cut and adjacent uncut reed patches was significantly higher than that in unmanaged reedbed. We assume this was caused by habitat heterogeneity, small size of cut patches and their rapid recolonization by arthropods from adjacent uncut patches. Our results suggest that in contrast to large-scale reed cutting, small-scale, mosaic reed cutting has no negative effect on nest survival and food abundance of reed passerine birds. However, given that we performed all experiments in June, i.e., when the reed was mature, our findings cannot be generalized to whole breeding period of all reed passerine birds. Therefore, temporal variation in nest predation rate and arthropod abundance in managed and unmanaged reedbeds during the entire breeding season should be examined in future studies.     

芦苇收割对震旦鸦雀觅食活动的影响

芦苇(Phragmites australis)湿地具有重要的社会经济价值和特殊的自然保育意义,芦苇收割是芦苇湿地管理的主要手段,往往对栖息于芦苇湿地中的动物群落产生影响,尤其对专食芦苇昆虫的鸟类影响较大。2007年1～4月,在长江口崇明岛崇西湿地科学实验站研究基地芦苇收割前后通过样方法研究了芦苇收割对震旦鸦雀(Paradoxornis heudei)觅食的影响。研究表明,芦苇收割显著减少了震旦鸦雀潜在食物资源,改变了震旦鸦雀觅食分布并使震旦鸦雀提前转移到新生芦苇枝上取食,芦苇收割后残留老芦苇枝对震旦鸦雀取食具有重要影响。芦苇收割时保留一定的斑块状和条带状老芦苇有利于震旦鸦雀利用新芦苇枝上潜在食物资源,可以在一定程度上缓解芦苇收割引起的震旦鸦雀食物短缺。     

Limited overlap of the community of bees and wasps (Hymenoptera: Aculeata) nesting in reed galls with those nesting in other cavities

Hymenopterans occurring in wetlands represent specific community with bioindicative characters but poorly understood nesting biology. We have studied the nesting preferences of these insects in ten reed beds—five represented by natural wetlands, and the other five localized to anthropogenic sites. We reared the hymenopterans from trap-nests consisting of reed stalks and goldenrod stems, which were installed at the localities through the nesting season, and compared them with quantitative data of hymenopterans reared from reed galls collected at the same localities. Most of the species that nested in reed galls accepted the reed stalk traps but not vice versa. Some of the species that accepted both these nesting resources strongly differed in their frequency of use of these two nesting resources. Moreover, the species composition differed substantially between goldenrod stems and either reed stalks or reed galls. The digger wasp Pemphredon fabricii was eudominant in reed galls with higher abundance at anthropogenic sites, while it was also observed in reed stalks but in much lower numbers. Hylaeus pectoralis was frequent in reed galls at both habitat types and only one individual was reared from reed stalks. Trypoxylon deceptorium was quite numerous in reed galls but much more frequent in reed stalks. Species unknown from reed galls (Psenulus pallipes, Hylaeus confusus, Gymnomerus laevipes) were numerous in reed stalks. We experimentally confirmed that P. fabricii and H. pectoralis show high preference of reed galls and are dependent on these nesting resources. The available evidence suggests that the management of both natural and anthropogenic sites needs to implement tools preserving reed beds, especially the terrestrial ones with reed galls.     

An investigation of dentinal fluid flow in dental pulp during food mastication: simulation of fluid–structure interaction

This study uses fluid–structure interaction (FSI) simulation to investigate the relationship between the dentinal fluid flow in the dental pulp of a tooth and the elastic modulus of masticated food particles and to investigate the effects of chewing rate on fluid flow in the dental pulp. Three-dimensional simulation models of a premolar tooth (enamel, dentine, pulp, periodontal ligament, cortical bone, and cancellous bone) and food particle were created. Food particles with elastic modulus of 2,000 and 10,000 MPa were used, respectively. The external displacement loading $(5\,\upmu \hbox {m})$ was gradually directed to the food particle surface for 1 and 0.1 s, respectively, to simulate the chewing of food particles. The displacement and stress on tooth structure and fluid flow in the dental pulp were selected as evaluation indices. The results show that masticating food with a high elastic modulus results in high stress and deformation in the tooth structure, causing faster dentinal fluid flow in the pulp in comparison with that obtained with soft food. In addition, fast chewing of hard food particles can induce faster fluid flow in the pulp, which may result in dental pain. FSI analysis is shown to be a useful tool for investigating dental biomechanics during food mastication. FSI simulation can be used to predict intrapulpal fluid flow in dental pulp; this information may provide the clinician with important concept in dental biomechanics during food mastication.     

Reedbed structure and habitat preference of reed passerines during the post-breeding period

Post-breeding habitats of nine passerine species were studied in the permanently flooded reed beds of ponds near the village Pusté úlany (SW Slovakia) in 2002. Structural features of reed beds and the abundance of all birds studied were sampled at two sites and eight study plots. The reed bed structure and abundance of four passerines differed considerably between the individual study plots. The variations in vegetation structure were also caused by winter reed burning in the SE part of study area. Stems in burnt reed beds were smaller and thinner than unburnt. Abundance of the reed warbler and to a lesser extent sedge warbler was higher in tall reed beds, while the bearded tit preferred thick reed stems. Position of reed beds along the shore — open water gradient was an important factor in terms of abundance at the study plots in the case of the reed bunting. This species showed a strong preference for the reed bed edge with open water. Horizontal distribution of other species seems to be random, however, the birds with the exception of Savi’s warbler preferred the upper stratum of reed bed in vertical distribution. Our field data corroborate with those found in experimental studies concerning with ecomorphological characteristics of birds. Some inconsistencies, however, could also be caused by other factors (e.g. foraging preferences). Comparison of breeding and post-breeding habitat requirements of the studied bird species confirmed a more or less random distribution of the majority of species in the post-breeding period. Some variation was found in the cases of only the reed warbler and bearded tit.     

Changes of element ratios of cultured cells from dune reed under adverse environmental conditions

Dune reed, as an ecotype of reed plant (Phragmites communis Trin.), is an ideal material for studies on the adaptations of plant to environmental conditions. Scanning electron microscope, energy-dispersive X-ray analysis, and plant tissue culture techniques were used to investigate the effect of extreme temperature, salt, and polyethylene glycol-induced osmotic stress on the intracellular elements K, Na, Ca, and Cl in cultured cells from dune reed and swamp reed (as control). The results indicated that the percentages of the studied elements in dune reed cells exposed to various stresses increased or decreased obviously compared to the swamp reed cells. It has been found that a pattern of absorbing K and discharging Na exists in dune reed cells, which did not exist in swamp reed cells. The pattern is thought to be a significant physiological mechanism of the dune reed response to adverse environmental factors. In addition, the percentages of Ca and Cl in dune reed cells were also shown to increase at high temperature. The growth of cells along with their surface features under different stress conditions were observed and the results are discussed.     

Water levels andPhragmites: Decline from lack of regeneration or dieback from shoot death

This contribution combines field observation with the literature to argue that stabilised water levels are contributing to reed decline through a lack of vegetative and generative reproduction, and that eutrophic conditions exacerbate this situation. The focus on what causes reed shoots to die has increased our knowledge of what limits the distribution of reed without necessarily increasing our understanding of reed decline. This raises the question as to whether reed beds are in fact dying, or whether reed decline is observable only in the absence of regeneration. The distribution pattern and life-history of reed suggests that generative reproduction is lacking. It is proposed that the temporal at which seedling establishment takes place is similar to the time-frame of observed reed decline (10–50 years). As an “encompassing” factor, water regime influences many of the specific factors under investigation. Its role is therefore consistent with agreement in the literature that reed decline is caused by combinations of factors.     

震旦鸦雀在镶嵌型芦苇收割生境中的巢址选择

大规模的芦苇收割会对在该生境中繁殖的鸟类产生严重影响。为降低芦苇收割对鸟类繁殖的负面影响,许多地区的湿地管理者逐渐采用了镶嵌型的芦苇收割方式。但是,这种新的芦苇管理方式对鸟类繁殖期生境选择的作用机理尚不清楚。震旦鸦雀是一种主要分布在我国东部、完全依赖芦苇生境而生存的珍稀鸟类,已被IUCN定为全球性近危物种。大规模的芦苇收割导致其适宜生境丧失,被认为是该物种面临的一个主要威胁。选择山东黄河三角洲国家级自然保护区为研究地区,采用AIC信息准则法,从巢址微生境、巢域斑块和全模型3个水平上对可能影响震旦鸦雀巢址选择的生境因子进行了逻辑斯蒂回归分析,并重点探讨芦苇镶嵌收割对其巢址选择的影响以及不同水平的相互效应。结果发现,震旦鸦雀的巢址选择受巢址微生境和巢域斑块尺度双重水平的影响,但巢址微生境因子的影响要大于巢域斑块因子。在巢址微生境水平上,影响震旦鸦雀巢址选择的因素有:1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度和巢的可见度;在巢域斑块水平上,影响因素包括芦苇生境类型、旧芦苇斑块面积的比例和植被盖度;在综合模型中,影响因素有1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度、巢的可见度和植被盖度。综上,震旦鸦雀倾向于在植被盖度较高、具有一定比例(18.3%)旧芦苇面积、1.5—2.5 m旧芦苇密度较高、可见度较低的生境斑块中筑巢。研究中,78.7%(n=141)的震旦鸦雀将巢筑在新旧芦苇混合的微生境中,其中36.9%的巢址附近旧芦苇的比例在一半以上;53.2%(n=111)的巢筑于新、旧两种芦苇茎秆之上,22.3%的巢的支撑芦苇中旧芦苇所占比例在一半以上。研究结果表明,旧芦苇在震旦鸦雀巢址选择和筑巢过程中发挥了重要作用。由于大范围的芦苇收割在微生境水平上可降低1.5—2.5 m旧芦苇的密度,在巢域斑块尺度上可降低旧芦苇斑块面积的比例,因此建议,在震旦鸦雀的繁殖地,未来的芦苇收割应采用镶嵌收割的形式,并至少应保留面积在20%以上的结构较好的旧芦苇斑块,以供震旦鸦雀选择巢址和繁衍后代。     

芦苇生态型划分指标的主分量及模糊聚类分析

运用主分量分析及模糊聚类的方法首次对包括群落、形态,解剖,生理生化及遗传代谢等４５个指标的不同生态芦苇进行了分析,结果表明,生物量、单株干重、株高,可溶性蛋白质含量、ＲＮＡ含量、ＤＮａａｓｅ和ＲＮａｓｅ活性、Ｋｒａｎｚ结构的有无及土壤ｐＨ值等差异最为显著。４种生态型芦苇中,盐化草甸芦苇与盐化草甸－沙丘过渡带芦苇最相近,其次为沙丘芦苇,沼泽芦苇与其它３种生态相似程度最低。     

乌梁素海野生芦苇群落生物量及影响因子分析

 对内蒙古乌梁素海湿地野生芦苇(Phragmites australis)生物量的调查基础上,探讨了富营养化湖泊湿地水体的物理化学性质对芦苇生物量的影响。结果表明：1）由于环境因子的影响,芦苇群落生物量变化较大,介于1.73～3.00 kg·m-2之间;地下和地上生物量之比介于1.14～2.19之间;2）芦苇群落生物量受多种因素的影响,其中水深是最主要的限制因子,水上生物量和地上生物量随着水深的增加而增加,而地下与地上生物量的比值则随水深的增加而减少,这主要是由于水深改变了芦苇群落的结构（群落密度）和个体形态(株高和株茎);3）芦苇群落生物量随着水体N浓度增加而增加。芦苇各器官（叶、茎、根状茎和根）的N∶P为7.59～12.21,小于14,这也说明该水体中的N负荷是影响芦苇生长的主要限制因子;4）土壤有机质分解对芦苇生长没有产生毒害作用。     

Analyses of Soluble Protein,Total and Free Amino Acids in Leaves of Different Ecotypes of Phragmites communis Growing in the Hexi Corridor

The difference of total and free amino acids and protein extracted from the leaves of four different reed ecotypes growing in Hexi corridor of Gansu Province were investigated. In all of the different reed ecotypes, the content of Asp, Glu, Gly, Leu and Ala in total amino acids were high, while the contents of Ala, Phe, Met and Thr, Pro in total amino acids varied among different reed ecotypes. Albeit Ala, Glu, Asp, Gly and Ser were the chief composition of free amino acids in leaves of all reed ecotypes, but temarkble difference was found in the content of each free amino acid from different reed ecotypes. The content of free Pro in leaves of salt meadow and salt meadow-sand dune transitional zone reed were 3.5 and 1.6 times respectively as much as in leaves of swamp reed. Swamp reed had 11 soluble proteins whereas other three reed ecotypes show that each has 13 soluble proteins. Three “salt adaptation proteins” (66 kD, 40.3 kD, 16.5 kD) were found in leaves of three reed ecotypes with varying degree of salt stress, however, the contents of 3 “salt adaptation protens” showed a negative correlation with the degree of salt stress. There was a large amount of “special protein” (11.7 kD) in leaves of sand dune reeds. These results suggest that the difference in cytogene expression takes a priority basis of adaptation of reed plants to different habitats, while a closer relationship of reeds tolerance to salt or drought stress with Pro accumulation in cells is seen than with the of accumulation stress adaptation protein.     

Seasonal changes of polyamines in habitat adaptation of different ecotypes of reed plants

The leaves of four reed ecotypes (Phragmites communis Trinius) growing in the desert regions of northwest China were investigated for levels of polyamines and activity of arginine decarboxylase (ADC; EC 4.1.1.19) during the growing season of 5 months. The polyamines in the leaves of all reed ecotypes consisted of putrescine, spermidine and spermine. The polyamine levels of the leaves were lower in the swamp reed than in the terrestrial reed ecotypes. Leaf polyamine levels decreased in all ecotypes over the course of the season. Compared to the swamp reed, the terrestrial reed ecotypes maintained higher ADC activity and a predominance of spermine, resulting in a lower ratio of putrescine to spermidine and spermine. It seems that the adaptation of reed plants to drought and saline habitats may be correlated with putrescine synthesis via the ADC pathway, and with a successful conversion of putrescine to spermidine and spermine.