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1.
增加林木的纤维素生产和转基因树的生长(英文) 总被引：6，自引：0，他引：6
纤维素是植物组成中的重要多聚物。纤维素也是重要的工业原料和可再生的能源物质。利用转基因技术可以降低林木中木质素含量并增加纤维素含量。木质素合成酶基因4-CL是一个重要的和木材再生有关的基因。在我们的研究中,将利用反义表达方法降低木质素含量,增加纤维素含量。研究包括:D4-CL基因的分离;转基因植物的生产;纤维素和木质素含量分析;中试。参69。 相似文献
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木质素生物合成及其基因调控的研究进展 总被引：3，自引：0，他引：3
木质素是地球上数量仅次于纤维素的有机物, 在植物生长发育中具有重要的生物学功能, 也是生物质能源的来源之一, 但在制浆造纸过程中, 将木材原料中木质素与纤维素分离, 不仅能耗高, 成本高, 而且废弃物还污染环境.林木木质素改良对于提高纸浆得率和质量、降低造纸经济成本以及环境保护, 都具有重要意义.文中介绍了木质素生物合成途径及其基因调控的研究进展, 此外, 还介绍了木质素生物合成基因调控的研究趋势, 主要是木质素特异性启动子、双价和多基因结构的共抑制以及转录因子的调控. 相似文献
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利用克隆得到的毛白杨c3h1基因构建其RNAi抑制表达载体,通过根癌农杆菌介导的叶盘法转化银腺杨无性系84 K,Realtime PCR检测表明其转基因株系323、325和322中c3h1基因表达量较野生型植株分别下调89.04%、82.22%和68.38%;茎横切片组化染色和显微结构观察表明转基因植株木质部发育和木质素沉积方式发生了改变;木质素、纤维素含量测定及苯酚—硫酸法总糖含量与HPLC法可溶性总糖和单糖含量检测结果表明:转基因植株木质素含量平均降低23.00%,最高可达39.71%;酸前处理效率最高提高了41.39%;未经酸处理直接酶解的糖化效率是对照植株的2.34～2.72倍,322株系和323株系比对照植株经酸前处理后再酶解的糖化效率高出81.18%和375.53%。 相似文献
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林木遗传工程及木质素的生物合成调节(英文) 总被引：1，自引：0，他引：1
林木遗传工程有利于保存林木遗传资源，改善全球气候，减轻自然林的过度采伐和满足人类日益增长的林木产品需求。控制林木真菌、病毒病、虫害和杂草的遗传工程方法正被广泛地研究和应用。尽管转基因林木的历史不长，种类不多，但它有广泛的应用前景。目前，抗除草剂基因、抗虫基因以及和木材质量相关的基因已被分离并应用于林木遗传工程。植物分子生物学和基因组学中的新技术使得高效林木遗传改良成为可能并将促进这些技术的商业化应用。木质素的应用已有一百年的历史，但木质素生物合成的全过程并不完全清楚。有关松树自然突变体和转基因林木的最新研究结果表明，木质素的生物合成是一个可以调节的过程。这些发现对完善木质素的生物合成途径、加深对木质素前体生物合成途径的理解和通过遗传工程改善木材质量有促进作用。本文综述了林木遗传工程在这些领域中取得的一些进展。 相似文献
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A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides, was cloned from cDNA prepared from secondary xylem of P tomentosa. Four anti-expression vectors with different fragments of PtoCesAl, named as pBIPF, pBICC1, pBIPR and pBIBR, were constructed. Some traits of transformed tobacco of pBICC1, pBIPR and pBIBR differed from wild types, such as small leaves, ＂dwarf＂ phenotype and thinner xylem and fiber cell walls than wild plants consistent with a loss of cellulose. It indicated that the growth of transgenic tobacco was restrained by the expression of anti-PtoCesA1. Transgenic tobacco was obtained and the contents of cellulose and lignin were analyzed as well as the width and length of fiber cells, and xylem thickness for both transgenic and control plants. Transformed tobacco showed a different phenotype from control plants and it implied that PtoCesA1 was essential for the cellulose biosynthesis in poplar stems. 相似文献
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David Castro Johanna Urzúa Mariano Rodriguez-Malebran Claudio Inostroza-Blancheteau 《Journal of Sustainable Forestry》2017,36(8):764-786
Woody leguminous species are valuable crops because of their nutritional, economic, and ecological characteristics. Such crops have aided in the recovery of marginal lands for agricultural development due to their ability to fix nitrogen, control erosion, and act as a refuge for other species, in addition to their capacity to improve soil mineral composition and microbial biodiversity. Nevertheless, some leguminous trees are recognized to be one of the worst invasive species that affect negatively biodiversity and the entire ecosystem balance. In this study, we review new global uses for some woody leguminous crops, highlighting new nutraceutical and pharmacological properties, their uses as bioenergy sources, and their ecological uses for bioremediation opening new possibilities of management. We aim to bring knowledge on the multiple benefits that these woody plants continue to provide to humans from economic, social, and environmental standpoints. 相似文献
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Kenaf (Hibiscus cannabinus) plants are widely known for their contribution to the global and regional environment because of their ability to fix CO2. On the other hand, some scientists have doubts about CO2 fixation by kenaf and have misgivings about the effect of kenaf on the ecosystem. We have characterized the structural characteristics
of cell walls of bast fibers, cores, roots, and leaves of kenaf during the maturation of plants and investigated the rate
of photosynthesis. During maturation of the kenaf plant the cellulose (bast fiber 52–59%, core 44–46%) and lignin (bast fiber
9.3–13.2%, core 18.3–23.2%) contents increased significantly. The aromatic composition of the lignin of bast fiber was significantly
different from that of the core lignin and of other plants. The lignin of bast fiber appears similar to pure syringyl lignin.
Fixation of CO2 by kenaf plants and their contribution to the global environment are discussed. A significatly high rate of photosynthesis
of kenaf plants was observed compared to that of woody plants in Japan, but the amount of CO2 fixation depends on the characteristics of the plantation. If the kenaf was planted in high density, about twice as much
CO2 was fixed as was fixed by trees in a tropical rain forest.
Received: April 22, 2002 / Accepted: July 24, 2002
Acknowledgments This project was supported by the Science and Technology Agency (STA) fellowship of the Japan International Science and Technology
Exchange Center (JISTEC), which has been successfully applied by Dr. Shuji Hosoya, Forestry and Forest Products Research Institute.
We thank Dr. Toshio Sumizono and Mr. Masao Sakurai, Forestry and Forest Products Research Institute, for their kind help in
determining the rate of photosynthesis and cultivating the kenaf plants, respectively. We also express our appreciation to
Dr. Quang Hung Le, College of Agriculture and Forestry, Ho Chi Minh City, Vietnam for offering information about the cultivation
of kenaf at Thu Duc District, Ho Chi Minh City. 相似文献
10.
林木遗传育种基础研究热点述评 总被引：1，自引：0，他引：1
林木由于世代周期长、个体高大、遗传负荷高等自身固有的一些特性,一直被认为是一种非常难以操作的遗传学材料,导致林木遗传育种在基础研究方面远远滞后于模式动、植物和其他重要作物,成为限制林木遗传改良进程的主要因素。分子育种是突破林木育种周期长的关键技术,通过基因组学研究,分析和阐明林木基因的功能是进行林木分子育种设计的前提。近年来随着生命科学领域新技术的快速发展,林木遗传育种基础研究也出现一些新的热点。本文主要阐述林木基因组和功能基因组学、连锁与关联分析、木材形成机制及分子育种技术的研究进展,虽然目前相关研究成果实际应用的条件还不成熟,但作为技术储备是急需加强的研究方向。 相似文献
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Short rotation woody crops are being developed as a sustainable source of biomass for the production of bioenergy, biofuels, and bioproducts. With the potential increase in demand of biomass for energy in the future, there is a need to diversify and expand its source. In the present study, we evaluated the growth performance, biomass production, energy content, and potential ethanol yields of shrub willow hybrids and native willow accessions. Shrub willow hybrids cuttings were obtained from the State University of New York through its controlled breeding program while cuttings used for native willow accessions were collected naturally. At the end of one rotation, consisting of three growing seasons, we found that shrub willow hybrids outperformed native willow accession species (P = 0.0004), with an average survival rate of 80 and 39 %, respectively. Biomass production of shrub willow hybrids and native willow accessions ranged from 7.42 to 16.0 and from 0.69 to 1.83 Mg ha?1 oven dry weight, respectively. The chemical composition (mass fraction % on dry basis) of willow hybrids and native willow accessions generally contained 39 % cellulose, 19 % hemicellulose, 25 % lignin, 1.4 % ash content, 17,500–18,500 kJ kg wood?1, and 385 L Mg?1 of theoretical ethanol yield. Energy content and potential ethanol yields on a dry weight basis did not vary between shrub willow hybrids and native willow accessions; however, the amount of biomass produced per unit land area is known to influence potential ethanol yields. Thus, we suggest that shrub willow hybrids offer promising potential as an alternative source of biomass. The results of our study suggest that four of the shrub willow hybrids evaluated have a greater potential for use as biomass energy crops on marginal lands in central Minnesota than the native willow accessions; hence, there is a need to test their potential at a larger scale. 相似文献
13.
A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides, was cloned from cDNA prepared from secondary xylem of P. tomentosa. Four anti-expression vectors with different fragments of PtoCesA1, named as pBIPF, pBICC1, pBIPR and pBIBR, were constructed. Some traits of transformed tobacco of pBICC1, pBIPR and pBIBR
differed from wild types, such as small leaves, “dwarf” phenotype and thinner xylem and fiber cell walls than wild plants
consistent with a loss of cellulose. It indicated that the growth of transgenic tobacco was restrained by the expression of
anti-PtoCesA1. Transgenic tobacco was obtained and the contents of cellulose and lignin were analyzed as well as the width and length of
fiber cells, and xylem thickness for both transgenic and control plants. Transformed tobacco showed a different phenotype
from control plants and it implied that PtoCesA1 was essential for the cellulose biosynthesis in poplar stems.
[Supported by the Hi-Tech Research and Development Program of China (863) (2001AA244060 and 2003AA244020) and National Basic
Research Program of China (973) (J1999016003)] 相似文献
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Effects of gaps on regeneration of woody plants: a meta-analysis 总被引：1，自引：0，他引：1
Forest gaps, openings in the canopy caused by death of one or more trees, have a profound effect on forest regeneration and drive the forest growth cycle. It is therefore necessary to understand the effects of forest gaps on regeneration for modern forest management. In order to provide a quantitative assessment of the effects of forest gaps on regen-eration of woody plants, we conducted this review of gap effects on woody plant regeneration on the basis of 527 observations from 42 indi-vidual papers, and reported the results of these data in a meta-analysis. Overall, densities of regenerated woody plants were significantly greater （359%） in forest gaps than on the closed-canopy forest floor. The regen-eration density in gaps of plantation forests was significantly greater （P＆lt;0.05） than that of natural forest because the regeneration in gaps of plan-tation forests was improved by both gap effects and experimental meas-ures. Similarly, in comparison to natural gaps, regeneration was better enhanced in artificial gaps. Regeneration density exhibited a significantly positive correlation with gap size, but a negative correlation with gap age because the gap size decreased with increasing gap age. Shade tolerance of woody plants affected regeneration density in gaps and understory. Average regeneration density of shade-tolerant species exhibited a sig-nificantly positive response to gaps but densities remained lower in total than those of intermediate and shade-intolerant species. Gap effects on regeneration decreased in response to increasing temperature and pre-cipitation because of the limiting effects of lower temperature and moisture on woody plant regeneration. In summary, forest gaps enhance woody plant regeneration, and the effects of gaps varied by forest type, gap characteristics, environmental factors and plant traits. The results of this meta-analysis are useful for better understanding the effects and roles of gaps on forest regeneration and forest management. 相似文献
16.
G. Moreno Marcos J. J. Obrador E. García E. Cubera M. J. Montero F. Pulido C. Dupraz 《Agroforestry Systems》2007,70(1):25-40
Dehesas are extant multi-purpose agroforestry systems that consist of a mosaic of widely-spaced scattered oaks (Quercus ilex L.) combined with crops, pasture or shrubs. We aimed to clarify the role of trees in dehesas of CW Spain focussed on the
analysis of tree-understorey interactions. Spatial variability of resources (light, soil moisture and fertility), microclimate,
fine roots of both herbaceous plants and trees and forage yield was measured. Additionally, we compared the nutritional and
physiological status, growth and acorn production of oaks in cropped (fodder crop), grazed (native grasses) and encroached
(woody understorey) dehesa plots. Significant light interception by trees was limited to the close vicinity of the trees,
with very low reduction away from them. Both microclimate and soil fertility improved significantly in the trees vicinity,
irrespective of soil management. Soil moisture varied very few with distance from the trees, as a result of the extended root
system of oaks. Root systems of trees and herbs did not overlap to a great extent. Crop production was higher beneath trees
than beyond the trees in unfertilised plots and foliar nutrient content of oaks did not increase significantly with crop fertilisation,
indicating that trees and crops hardly compete for nutrients. Moreover, trees benefited from the crop or pasture management:
trees featured a significantly improved nutritional and physiological status, a faster growth and a higher fruit productivity
than trees growing in encroached or forest plots. 相似文献
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为清楚了解、掌握河北小五台山国家级自然保护区野生木本植物资源情况,并妥善加以利用,采用野外实地调查的方法对小五台山野生有色木本植物进行研究。调查发现,小五台山内野生有色木本植物资源丰富,许多物种在不同生长季的树叶、树干、花及果实具有极高的观赏性,部分果实还具有可食性;保护区常见的有色木本植物共116种,隶属于33科67属,以蔷薇科、桦木科、榆科、卫矛科、忍冬科为主,其中观叶植物64种、观枝观干植物12种、观果植物37种;观叶树种可在园林绿化中应用,观果树种具有食用和药用价值,部分树种可应用于防护林建设;因此,应加强野生有色木本植物保护,合理利用,建立彩色植物园,加快引种、驯化、繁育基地的建设,丰富彩色木本植物资源,实现野生有色木本植物资源的可持续利用。 相似文献
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江西武夷山自然保护区森林群落木本植物多样性垂直规律研究 总被引：3，自引：0，他引：3
基于海拔500～2000m之间每隔100m设置的14个样地调查研究。对江西武夷山主峰黄岗山西北坡森林群落结构特征、木本植物多样性及其与海拔梯度的关系进行探讨。14个样地共记录木本植物57科108属215种,其中乔木43科80属149种。全部样方中乔木树种分为常绿阔叶、落叶阔叶和针叶3种生活型,其中常绿阔叶树85种、落叶阔叶树59种、针叶树5种。研究结果表明:①常绿阔叶林一般分布在海拔1300m以下,针阔混交林分布在海拔1400～1800m,1800m以上为山顶矮林。②物种丰富度、α多样性、β多样性指数沿海拔梯度的变化趋势是:木本植物物种丰富度指数、Shannon-wiener指数、Pielou均匀度指数与海拔成显著负线性相关关系。Cody指数随海拔的升高而降低,Jaccard相似系数与海拔梯度无明显规律。 相似文献
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木素及其衍生物在农、林业中的应用 总被引：1，自引：0，他引：1
木素及其衍生物主要是来自木材制浆和造纸工业的副产物，即硫酸盐（或碱）木素、木素磺酸盐或木材水解工业产生的剩余物，即水解木素。过去这些木素大多作为燃料使用，为了提高木材利用率和增加工厂经济效益，科学工作者研究了关于木素及其衍生物在工、农（林）业生产中的应用，并取得了很多成就。本文评述了木素及其衍生物在农、林业中的应用，包括：植物生长刺激剂、含氮木素肥料、含微量元素木素肥料、土壤改良剂、动物饲料添加剂、农药缓慢释放剂等。 相似文献
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Sam Riffell Jake VerschuylDarren Miller T. Bently Wigley 《Forest Ecology and Management》2011,261(4):878-887
Forest harvest operations often produce large amounts of harvest residue which typically becomes fine (foliage, small limbs and trees) and coarse woody debris (snags and downed logs). If removed at harvest, residual biomass has potential to be a local energy source and to produce marketable biofuel feedstock. But, CWD in particular serves critical life-history functions (e.g., breeding, foraging, basking) for a variety of organisms. Unfortunately, little is known about how forest biodiversity would respond to large scale removal of harvest residues. We calculated 745 biodiversity effect sizes from 26 studies involving manipulations of CWD (i.e., removed or added downed woody debris and/or snags). Diversity and abundance of both cavity- and open-nesting birds were substantially and consistently lower in treatments with lower amounts of downed CWD and/or standing snags, as was biomass of invertebrates. However, cumulative effect sizes for other taxa were not as large, were based on fewer studies, and varied among manipulation types. Little is currently known about biodiversity response to harvest of fine woody debris. Predicting the effects of biomass harvests on forest biodiversity is uncertain at best until more is known about how operational harvests actually change fine and coarse woody debris levels over long time periods. Pilot biomass harvests report post-harvest changes in CWD levels much smaller than the experimental changes involved in the studies we analyzed. Thus, operational biomass harvests may not change CWD levels enough to appreciably influence forest biodiversity, especially when following biomass harvest guidelines that require leaving a portion of harvest residues. Multi-scale studies can help reduce this uncertainty by investigating how biodiversity responses scale from the small scale of manipulative experiments (i.e., 10-ha plots) to operational forest management and how biodiversity response to CWD levels might vary at different spatial and temporal scales and in different landscape contexts. 相似文献