能源植物新秀--芒草

化石能源日益紧缺,污染日趋严重,新能源的开发和利用成为时代的迫切要求。在寻找新能源的过程中,芒草逐渐进入人们的视线。随着研究的深入,“高个子”芒草已经成为能源植物中的佼佼者。     

关于我国林业生物质能源发展的政策思考

本文重点介绍了国内外生物质能源发展趋势,概括和分析了当前我国林业生物质能源发展的潜力及存在的问题,提出了中国林业生物质能源发展的思路及推进其产业化发展的相关政策需求和建议。     

生物柴油的国际发展现状和前景

生物质能源具有优良的环保特性,是一种再生的生物能源,它有着循环生产和利用的优良特性,又便于人为控制,比起除光、电、水、风能以外的其他能源来,可算是一种新开辟的廉价可持续能源,它对那些能源自给度不高的地区和国家具有非常重要意义。     

生物质能源四十年

为应对1973年全球石油危机而发展起来的现代生物质能源已渐趋成熟,在对化石能源的替代中发挥着越来越突出的作用。回顾了生物质能源40年的发展历程,对液体生物燃料、生物天然气和固体生物燃料与发电作了专门叙述。就生物质能源与中国,以及中国发展生物质能源方略发表了自己的见解。     

｜本研究人员构建适合寒冷地区种植的转基因芒草品系

日本北海道大学北方生物圈野外科学中心的山田敏彦教授等的研究团队,在世界上首次成功构建出芒草属植物的转基因体。芒草属的植物,作为可以在寒冷地区栽培的能源植物是非常重要的。由于转基因品系的确立,今后就有可能赋予其更适合生产能源的性状。研究成果于2011年1月31日,公布在GlobalChangeBiologyBioenergy杂志的网络版上。巨型芒草（GiantMiscanthus）作为用来生产生物乙醇等的生物质候选植物,备受关注。也有不少人试图构建转基因品系,可是尚无有关成功的报道。之所以这么困难,     

能源植物甜高粱种质资源和分子生物学研究进展

世界能源危机和全球生态环境日益恶化迫使人们急需开发可再生能源。生物质能源作为一种清洁的可再生能源已受到世界各国的高度重视。发展生物质能源的瓶颈之一是生物质原料不足。甜高粱的生物学产量和含糖量极高, 同时兼有耐旱、耐涝、耐贫瘠和耐盐碱等诸多优良特性, 被认为是最具开发潜力的能源植物之一。该文从甜高粱的分类学、生物学特点、种质资源评价、功能基因以及基因组信息等方面综述了甜高粱的最新研究进展和存在的问题, 并展望了甜高粱作为能源植物的研发前景。     

能源植物甜高粱种质资源和分子生物学研究进展

世界能源危机和全球生态环境日益恶化迫使人们急需开发可再生能源。生物质能源作为一种清洁的可再生能源已受到世界各国的高度重视。发展生物质能源的瓶颈之一是生物质原料不足。甜高粱的生物学产量和含糖量极高,同时兼有耐旱、耐涝、耐贫瘠和耐盐碱等诸多优良特性,被认为是最具开发潜力的能源植物之一。该文从甜高粱的分类学、生物学特点、种质资源评价、功能基因以及基因组信息等方面综述了甜高粱的最新研究进展和存在的问题,并展望了甜高粱作为能源植物的研发前景。     

农村废弃生物质资源开发获重要突破

能源危机是当今世界面临的严峻挑战之一[1].化石能源是地球亿万年间积累起来的光合产物,是不可再生的资源.大量化石能源开挖后,沉睡了数亿年的"碳库"最终又要变成"碳源",这使人类本来任务艰巨的碳减排 "雪上加霜"[2,3].为逃脱化石能源怪圈,全球能源与环境科学家们,把精力转移到用太阳能、风能、生物质能等清洁能源代替化石能源上来,取得了重要进展.但新能源开发仍存在着成本高,经济效益差的不足[4～6].作为全球最大的发展中国家,中国科学家正努力寻找能高效利用农村生物质资源的新方法.研究成果一旦获得推广,可大大缓解能源紧缺状况,对全球碳减排意义重大 [7,8].     

序言

<正>能源可持续发展关系到我国经济发展和能源的安全。随着我国经济社会快速发展,资源,特别是能源资源的安全问题,已成为制约我国国民经济发展的主要矛盾。随着我国经济的快速增长和人口的增加,我国又面临着温室气体减排的巨大压力与生态安全危机。因此,必须及早改善我国能源结构,提高可再生能源的比例。生物质能是可再生能源的重要组成部分。在过去的150多年内,世界能源发展先后出现了3个波峰:19世纪中叶前,是农业文明时期,主要是生物质燃料,低碳经济;20世纪初,     

合成生物学在生物燃料上的应用趋势及展望

近年来,世界各国都面临着化石能源日益枯竭、人口增长、温室气体排放增加、环境日益恶化等危机,寻找可再生的清洁替代能源已成为人类最紧迫的任务之一,燃料乙醇、生物柴油等可再生的生物质能源成为世界各国研究的重点。尽管近年来生物燃料的研发已经取得了很多进展,但其商业化发展仍然面临着转化效率低、生产成本高等难题。     

Miscanthus: A fast‐growing crop for environmental remediation and biofuel production

As an herbaceous perennial, Miscanthus has attracted extensive attention in bioenergy refinery and ecological remediation due to its high yield and superior environmental adaptability. This review summarizes current research advances of Miscanthus in several aspects including biological properties, biofuels production, and phytoremediation of contaminated soil. Miscanthus has relatively high biomass yield, calorific value, and cellulose content compared with other lignocellulosic bioenergy crops, which make it one of the most promising feedstocks for the production of second‐generation biofuels. Moreover, Miscanthus can endure soil pollutions caused by various heavy metals and survive in a variety of adverse environmental conditions. Therefore, it also has potential applications in ecological remediation of contaminated soil, and reclamation of polluted soil and water resources. Nevertheless, more endeavors are still needed in the genetic improvement and elite cultivar breeding, large‐scale cultivation on marginal land, and efficient conversion to biofuels, when utilizing Miscanthus as a bioenergy crop. Furthermore, more efforts should also be undertaken to translate Miscanthus into a bioenergy crop with the phytoremediation potential.     

The ecology and agronomy of Miscanthus sinensis, a species important to bioenergy crop development, in its native range in Japan: a review

Among several candidate perennial taxa, Miscanthus × giganteus has been evaluated and promoted as a promising bioenergy crop. Owing to several limitations, however, of the sterile hybrid, both at the taxon and agronomic production levels, other options need to be explored to not only improve M . × giganteus , which was originally collected in Japan, but to also consider the development of other members of its genus, including Miscanthus sinensis , as bioenergy crops. Indeed, there is likely much to be learned and applied to Miscanthus as a bioenergy crop from the long history of intensive interaction between humans and M. sinensis in Japan, which in some regions of the country spans several thousand years. Combined with its high amount of genetic variation, stress tolerance, biotic interactions with fauna, and function as a keystone species in diverse grasslands and other ecosystems within its native range, the unique and extensive management of M. sinensis in Japan as a forage grass and building material provides agronomists, agroecologists, and plant breeders with the capability of better understanding this species in terms of potential contribution to bioenergy crop development. Moreover, the studies described in this review may serve as a platform for future research of Miscanthus as a bioenergy crop in other parts of the world.     

Adult activity and oviposition of corn rootworms,Diabrotica spp. (Coleoptera: Chrysomelidae), in Miscanthus,corn and switchgrass

The ability of the biomass crop Miscanthus (Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize) to support larval development for both United States and European populations of the western corn rootworm, Diabrotica virgifera virgifera LeConte, suggests an avenue for interactions with corn (Zea mays L.). To provide context to survival of D. v. virgifera on Miscanthus, adult activity and oviposition of Diabrotica spp. were monitored in central Illinois in 2010–2011 in Miscanthus, corn and switchgrass (Panicum virgatum L.). For D. v. virgifera, vial traps within corn plots captured 3–10 times as many adults as in Miscanthus or switchgrass, while soil samples showed females laid approximately 10 times as many eggs in corn as in the perennial grasses. Adult southern corn rootworms, Diabrotica undecimpunctata howardi Barber, were the most abundant species in 2010 and clearly preferred switchgrass as an adult habitat, with vial traps in switchgrass capturing 5–10 times as many D. u. howardi as those in corn or Miscanthus. Based on the small production areas for Miscanthus and switchgrass (and low use of both by D. v. virgifera), it seems likely that there are no current impacts of these perennial grasses on pest status of Diabrotica spp. in corn or other crops. However, adaptations by Diabrotica spp. to pest management practices suggest they could be a source for interactions between biomass and food or feed crops. Early‐season soil samples did not recover eggs of D. u. howardi, but their use of switchgrass as an adult habitat suggests additional research in areas where switchgrass may be grown near peanuts, alfalfa or other hosts may be needed. Also, investigation of other candidate bioenergy crops known to support Diabrotica spp. larval development is needed to better understand the possible effects of a changing agricultural landscape on corn rootworms.     

Effect of temperature on photosynthesis of Miscanthus clones collected from different elevations

Six to twenty-eight months after transplanting, the net photosynthetic rate (PN) of Miscanthus leaves was measured at leaf temperatures between 18 to 37 °C. PN of clones from high mountain areas was more adaptable to low temperature, while that of clones from low mountain areas was more adaptable to high temperature. The clones from the lowlands were best adapted to both high and low temperatures. These characteristics lasted at least 28 months after transplanting. Thus Miscanthus had differentiated into different ecotypes to adapt to the thermal environments of different elevations. Comparison of the PN values measured in different seasons and durations after transplanting indicated that PN in Miscanthus could acclimate to environments with various temperature ranges resulting from elevation and seasonal changes.     

Effect of temperature on photosynthesis of Miscanthus clones collected from different elevations

Six to twenty-eight months after transplanting, the net photosynthetic rate (PN) of Miscanthus leaves was measured at leaf temperatures between 18 to 37 °C. PN of clones from high mountain areas was more adaptable to low temperature, while that of clones from low mountain areas was more adaptable to high temperature. The clones from the lowlands were best adapted to both high and low temperatures. These characteristics lasted at least 28 months after transplanting. Thus Miscanthus had differentiated into different ecotypes to adapt to the thermal environments of different elevations. Comparison of the PN values measured in different seasons and durations after transplanting indicated that PN in Miscanthus could acclimate to environments with various temperature ranges resulting from elevation and seasonal changes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Overwintering problems of newly established Miscanthus plantations can be overcome by identifying genotypes with improved rhizome cold tolerance

Miscanthus , a perennial rhizomatous C₄ grass, is a potential biomass crop in Europe, mainly because of its high yield potential and low demand for inputs. However, until recently only a single clone, M. × giganteus , was available for the extensive field trials performed across Europe and this showed poor overwintering in the first year after planting at some locations in Northern Europe. Therefore, field trials with five Miscanthus genotypes, including two acquisitions of Miscanthus × giganteus , one of M. sacchariflorus and two hybrids of M. sinensis were planted in early summer 1997 at four sites, in Sweden, Denmark, England and Germany. The field trials showed that better overwintering of newly established plants at a site was not apparently connected with size or early senescence. An artificial freezing test with rhizomes removed from the field in January 1998 showed that the lethal temperature at which 50% were killed (LT₅₀) for M. × giganteus and M. sacchariflorus genotypes was −3.4 °C. However, LT₅₀ in one of the M. sinensis hybrid genotypes tested was −6.5 °C and this genotype had the highest survival rates in the field in Sweden and Denmark. Although the carbohydrate content of rhizomes, osmotic potential of cell sap and mineral composition were not found to explain differences in frost tolerance adequately, moisture contents correlated with frost hardiness (LT₅₀) in most cases. The results obtained form a basis for identifying suitable Miscanthus genotypes for biomass production in the differing climatic regions of Europe.     

Characterization of Miscanthus cell wall polymers

Efficient utilization of lignocellulosic Miscanthus biomass for the production of biochemicals, such as ethanol, is challenging due to its recalcitrance, which is influenced by the individual plant cell wall polymers and their interactions. Lignocellulosic biomass composition differs depending on several factors, such as plant age, harvest date, organ type, and genotype. Here, four selected Miscanthus genotypes (Miscanthus sinensis, Miscanthus sacchariflorus, Miscanthus × giganteus, Miscanthus sinensis × Miscanthus sacchariflorus hybrid) were grown and harvested, separated into stems and leaves, and characterized for their non‐starch polysaccharide composition and structures, lignin contents and structures, and hydroxycinnamate profiles (monomers and ferulic acid dehydrodimers). Polysaccharides of all genotypes are mainly composed of cellulose and low‐substituted arabinoxylans. Ratios of hemicelluloses to cellulose were comparable, with the exception of Miscanthus sinensis that showed a higher hemicellulose/cellulose ratio. Lignin contents of Miscanthus stems were higher than those of Miscanthus leaves. Considering the same organs, the four genotypes did not differ in their Klason lignin contents, but Miscanthus × giganteus showed the highest acetylbromide soluble lignin content. Lignin polymers isolated from stems varied in their S/G ratios and linkage type distributions across genotypes. p‐Coumaric acid was the most abundant ester‐bound hydroxycinnamte monomer in all samples. Ferulic acid dehydrodimers were analyzed as cell wall cross‐links, with 8‐5‐coupled diferulic acid being the main dimer, followed by 8‐O‐4‐, and 5‐5‐diferulic acid. Contents of p‐coumaric acid, ferulic acid, and ferulic acid dimers varied depending on genotype and organ type. The largest amount of cell wall cross‐links was analyzed for Miscanthus sinensis.     

Application of the AquaCrop model to simulate the biomass of Miscanthus x giganteus under different nutrient supply conditions

There are conflicting opinions about the need to fertilize Miscanthus and, also, the question has been raised whether Miscanthus should be irrigated, especially if water resources are limited. Crop growth modeling can help answer such questions. In this article the FAO AquaCrop water‐driven model was selected to simulate Miscanthus biomass under different nutrient and water supply conditions. The article reports the outcomes of 6‐year experiments with Miscanthus on two locations in Serbia: Zemun, where three fertilizer treatments were applied (N_l – 100 kg ha^?1, N_opt 50 kg ha^?1 and N_f nonfertilized), and Ralja, where only N_l 100 kg ha^?1 was applied. Model calibration focused on the measured data (root depth, crop phenology, and the above‐ground biomass by year of growth. Calibration results showed a very good match between measured and simulated values. The largest and only significant difference was noted in 2008, when the crop was establishing and exhibited uneven radication. The simulation results for the next 5 years showed a variance from ?4 to 5.7%, believed to be a very good match. A high coefficient of determination (R² = 0.995) and high Willmott index of agreement (0.998) were also indicative of a good match between simulated and recorded biomass yields. The measured and simulated results for validated datasets at both locations were good. The average RMSE was 2.89 Mg ha^?1; when compared to the deviations noted at the test site itself, it was apparent that they were smaller in all the years of research except the first year. The index of agreement was 0.97 and the coefficient of determination R² 0.947. The AquaCrop model can be used with a high degree of reliability in strategic planning of Miscanthus cultivation in new areas, under different nutrient and water supply and local weather and soil conditions.     

Semichemical pulping of Miscanthus giganteus. Effect of pulping conditions on some pulp and paper properties

Miscanthus is an interesting raw material for pulp production, it is a high yield low maintenance plant with a high cellulose and hemicellulose content. Its semichemical pulp can be beneficial in paper for cardboard production process, which nowadays is usually made from secondary fibers, by increasing the mechanical properties of the paper produced. In this study, the influence of the percentage of NaOH used related to the dry Miscanthus weight, digestion time and refining time on some pulp and paper properties have been studied and compared with pulp obtained from commercial fluting paper (CF). Fiber size distribution of the Miscanthus pulp was found to contain a higher fines (less than 0.2 mm) percentage than the CF pulp. Hand-sheets made from Miscanthus pulp showed better mechanical properties than the ones made with the CF pulp. CMT, RCT and CCT indexes were higher when using 100% Miscanthus pulp or mixtures of Miscanthus and CF pulp. The only property which worsened was Gurley porosity. Of the three operational variables changed, refining time exerts the most significant influence on the pulp and paper properties measured.     

Yield‐biodiversity trade‐off in patchy fields of Miscanthus × giganteus

Increasing crop productivity to meet rising demands for food and energy, but doing so in an environmentally sustainable manner, is one of the greatest challenges for agriculture to date. In Ireland, Miscanthus × giganteus has the potential to become a major feedstock for bioenergy production, but the economic feasibility of its cultivation depends on high yields. Miscanthus fields can have a large number of gaps in crop cover, adversely impacting yield and hence economic viability. Predominantly positive effects of Miscanthus on biodiversity reported from previous research might be attributable to high crop patchiness, particularly during the establishment phase. The aim of this research was to assess crop patchiness on a field scale and to analyse the relationship between Miscanthus yield and species richness and abundance of selected taxa of farmland wildlife. For 14 Miscanthus fields at the end of their establishment phase (4–5 years after planting), which had been planted either on improved grassland (MG) or tilled arable land (MT), we determined patchiness of the crop cover, percentage light penetration (LP) to the lower canopy, Miscanthus shoot density and height, vascular plants and epigeic arthropods. Plant species richness and noncrop vegetation cover in Miscanthus fields increased with increasing patchiness, due to higher levels of LP to the lower canopy. The species richness of ground beetles and the activity density of spiders followed the increase in vegetation cover. Plant species richness and activity density of spiders on both MT and MG fields, as well as vegetation cover and activity density of ground beetles on MG fields, were negatively associated with Miscanthus yield. In conclusion, positive effects of Miscanthus on biodiversity can diminish with increasing productivity. This matter needs to be considered when assessing the relative ecological impacts of developing biomass crops in comparison with other land use.