我国非豆科固氮树种在林业上的应用研究现状

生物固氮是大气中氮素向森林生态系统中输入的一个重要途径。木本共生固氮是重要的固氮资源,非豆科木本固氮植物结瘤范围广,随着新的种属的不断发现和弗氏放线菌的分离成功,非豆科共生固氯已成为当前生物固氮研究中的活跃领域之一。本文较全面地介绍了我国非豆科固氮树种在林业上的应用研究现状,并指出了有待进一步研究的问题。     

我国林木固氮的研究现状和前景展望

林木固氮已成为当前我国急需解决的重大课题之一。作者对生物固氮的研究现状和我国林木固氮研究的概况进行了综合分析,并针对当前我国林木固氮存在的问题,提出了今后的研究方向。     

几种木本植物联合固氮细菌的研究——联合固氮细菌的分离鉴定及固氮活性

在几种木本植物杨树、杉木、油茶根际存在着联合固氮体系 ,从它们根际分离到 2 6株具有较高固氮酶活性的菌株 .筛选了 4株具有高固氮活性的菌株 Aa33、Ba41、y12、Y2 2进行固氮特性研究 ,并选择菌株 y12、Y2 2进行形态、培养特征及生理生化研究 ,初步鉴定为黄杆菌属 F lavobacterium和产碱菌属 Alcaligenes.这对今后开展木本植物固氮领域的研究及其利用具有现实的指导意义 .     

刺槐固氮能力测定与应用

随着土壤肥力降低、沙化及贫瘠坏境的日益恶化,加之工业制氮存在的种种弊端,对生物固氮的需求逐渐增大。刺槐作为重要的豆科固氮植物,其固氮的应用研究也日益重要。作者通过查阅分析国内外刺槐固氮相关研究,对生物固氮能力的测定方法、刺槐的固氮特性、刺槐根瘤固氮的测定方法进行了阐述,并对刺槐固氮作用的应用前景与优势进行分析和预测。     

磁生物肥对长白落叶松换床苗生长的影响

磁生物肥是一种用磁化处理技术培殖的生物固氮组合肥。它是由多种固氮微生物及微量元素经磁化组合成的,具有较强的固氮活性,其机理是利用氮气作养料达到肥田增产的效果。近年来磁生物肥在农业上已开始应用,为探索磁生物肥在林业上的应用效果,我们于1991年春在吉林市松花江苗圃对长白落叶松进行了浸根换床试验,经测定效果显著,     

我所沙棘共生固氮研究概况

山西省生物研究所的沙棘共生固氮研究工作是从1979年开始的。在70年代末,我所为了改变山西土壤贫瘠的状况,提出了《生物固氮的研究》课题,这是目前世界各国都在从各个不同的方面进行研究,是难度较大,涉及范围较广的一项生物技术研究课题。当时主管我所业务的副所长杜竹铭教授(现在山西农业大学)根据国外的有关资料写出了《固氮生物是一项重要的农业资源》,在当时召开的全省农业资源普查工作会议上介绍以后,受到了与会人员的极大重视,并决定把固氮植物资源的调查列为全省农业资源普查的一项内容。以后在全省的普查中发现了非豆科固氮植物——沙棘和翅果     

抗冻诱导因子CBF基因及其在木本植物的抗寒应用

温度是植物生长发育的必要条件,低温是影响植物生长发育的重要逆境因子,因此抗冻诱导因子CBF基因作为重要的抗逆系列基因成为目前研究的热点之一。系统介绍了CBF基因家族、结构与特性、表达、调节因子、生理生化功能、抗逆条件下的交叉适应现象,及其在木本植物上的应用前景及原理。     

生物固氮在林业中的应用和研究

本文介绍了生物固氮在东南亚、澳大利亚和新西兰、欧洲和北美林业中的应用和研究情况。其中北美的研究较深入,主要包括(1)共生的性质;(2)宿主植物改良;(3)氮的固定和积累;(4)共生系统对森林生态系统的影响;(5)共生固氮系统的管理。     

盐胁迫下沙枣生物固氮能力及氮素分配研究

[目的]应用15N自然丰度法研究盐胁迫条件下沙枣的生物固氮能力,并探讨几个耐盐树种的氮素分配情况。[方法]通过耐盐树种的室内砂培试验,确定盐渍生境条件下以空气氮为唯一氮源的沙枣15N相对丰度B值及其适宜的参比植物;估测室内和野外盐渍生境中沙枣的生物固氮能力;并通过测定碳、氮、磷元素含量探讨了几种耐盐树种的氮素分配情况。[结果]室内盐胁迫砂培试验条件下,沙枣的B值为-1.41‰;柽柳和白蜡可作为沙枣的参比植物;沙枣的生物固氮百分率为55.03%。野外中度盐渍环境中,沙枣生物固氮百分率为69.69%。试验条件下,沙枣、柽柳和白蜡3个耐盐树种中,沙枣植株及其叶、茎、根含氮量最高,且与其它树种差异显著(P0.05);沙枣植株氮/碳含量比以及氮/磷含量比最高;沙枣叶、茎和根的氮/磷含量比最高。野外中度盐渍环境中,沙枣叶的氮/碳含量比以及氮/磷含量比均为最高。[结论]15N自然丰度法可用于研究盐胁迫条件下沙枣的生物固氮能力,柽柳和白蜡可作为参比植物;沙枣在盐胁迫下的固氮能力较强,是可应用于盐渍土生物改良的优良树种。本文为盐胁迫条件下利用15N自然丰度法研究生物固氮作用提供方法参考,对于盐碱地生物治理中植物材料的选择和耐盐树种资源的综合开发利用具有重要意义。     

生物固氮林业中应用和研究

为迅速发展速生优质人工林,不断提高森林生产力,一些林业发达的国家已开始实行以氮素为主的规模宏大的森林施肥计划,其中生物固氮得到世界各国林学家的重视,被列入国际生物学计划和人与生物圈计划.由于各地区自然条件和固氮植物资源不同,林业经营的传统和集约程度也有差异.现仅就以下国家生物固氮情况作一简介.     

植物凝集素及其在生物固氮中的作用

讨论了植物凝集素的性质、种类和分布,研究表明根瘤菌是通过对凝集素的识别来浸染植物的,因此人们提出将豆科植物的凝集素转移到其他植物中去,再接种豆科植物的根瘤菌,则可以使其他植物也被根瘤菌浸染,从而使其他植物也具有固氮的能力。     

Biological nitrogen fixing capacity and biomass production of different understorey pastures in a Pinus radiata-pasture agroforestry system in New Zealand

Quantitative field measurements of biological nitrogen fixation (BNF) and biomass production by four different understorey pastures in a Pinus radiata-pasture agroforestry system were determined over a period of one year. The trees were two years old at the beginning of this study and the understorey pastures were being cut and removed for silage. The BNF was determined using the ¹⁵N dilution technique. Pastures of ryegrass+clover, cocksfoot+clover, phalaris+clover and lucerne were used. Substantial amounts of BNF were found (71 to 230 kg N ha^–1 year^–1) with lucerne showing the highest N fixation. However, lucerne derived only 71 to 72% of its N from the atmosphere (%Ndfa) during the spring/summer period compared to 83–97% with clovers, thus the net N demand from the soil was substantially higher with lucerne. This caused increased N stress to the trees. Clover in ryegrass+clover pasture fixed more N than the other grass+clover pastures. Although pasture position in relation to trees did not affect annual pasture total DMY and %Ndfa, pastures north of tree row grew better than those in other positions. Trees significantly affected the BNF of legumes and the botanical composition of pastures with highest BNF and legume production occurring in pastures midway between two rows of trees. These results suggest that it would be advantageous to evaluate different legumes and grasses for tolerance of shade and moisture stress in future studies. As the trees studied were only 1.5 to 3 m in height, their effects on BNF, seasonal pasture biomass production and botanical composition are expected to increase with tree dominance in the ecosystem with time. Amounts of N fixed were related to the productivity (i.e. dry matter and N yield) and seasonal persistence of the legumes. The productivity was high in spring and summer and low in autumn and winter.     

固氮树种在混交林中的作用

豆科及非豆科固氮树种是重要的生物固N资源。作为混交树种,在混交林中发挥着改善林地养分及水分状况,维持地力,提高林地生产力,很好地促进主要树种生长的重要作用。     

森林土壤氮贮量及氮素输入过程研究进展

森林土壤是氮最重要的贮藏库,且发挥着重要的氮源、汇和库的功能,而其氮素贮存和输入过程也显著影响着森林生态系统的结构和功能.自工业革命以来,人类活动已经显著改变了全球的氮素输入,造成了森林衰退及一系列严重的环境问题,所以森林土壤氮贮量及氮输入过程的研究已成为当前研究的热点.文中综述了森林土壤氮贮量和生物固氮、大气氮沉降、凋落物归还、施肥等氮素输入途径的研究现状,并对研究中存在的不确定性和争论焦点问题进行了提纯、分析.最后,归纳出该领域研究的不足和今后的发展趋势.     

Effects of VA mycorrhizae and Frankia dual inoculation on growth and nitrogen fixation of Hippophae tibetana

Through biological inoculation technology, the joint symbiosis of Tibetan seabuckthorn (Hippophae tibetana) in pure culture was identified and the effects of dual inoculation with Frankia and mycorrhizal fungi on the host plants in pot cultures were investigated. The results obtained from the comparative study showed that H. tibetana could form nodules and VA mycorrhiza both in pot and pure cultures. VA mycorrhizae and Frankia can stimulate the growth and the nitrogen fixation ability of host plants, respectively, yet the stimulation of the dual inoculation on the growth and nitrogen fixation ability of the host plants was more significant (p<0.05): stronger nitrogen-fixing ability, higher VA mycorrhizal development and better growth of seedlings in VAH and HR16 dual inoculation.     

森林土壤氮贮量及氮素输入过程研究进展

森林土壤是氮最重要的贮藏库,且发挥着重要的氮源、汇和库的功能,而其氮素贮存和输入过程也显著影响着森林生态系统的结构和功能。自工业革命以来,人类活动已经显著改变了全球的氮素输入,造成了森林衰退及一系列严重的环境问题,所以森林土壤氮贮量及氮输入过程的研究已成为当前研究的热点。文中综述了森林土壤氮贮量和生物固氮、大气氮沉降、凋落物归还、施肥等氮素输入途径的研究现状,并对研究中存在的不确定性和争论焦点问题进行了提纯、分析。最后,归纳出该领域研究的不足和今后的发展趋势。     

黑木相思根瘤菌在厚荚相思苗木上的效应

为了探讨不同相思树种根瘤菌互接种的效应,将黑木相思根瘤菌接种到厚荚相思苗木上,采用随机区组盆栽试验方法,研究苗木的结瘤、生长和固氮能力.结果表明:接种黑木相思根瘤菌能明显增加厚荚相思苗木的结瘤,证明不同相思树种之间,其共生的根瘤菌对宿主的要求并不十分的严格;但是,不同菌株对苗木的生长效应和固氮能力上存在明显的差别.因此,在开发根瘤菌资源时,应充分注意树种与菌株的匹配问题,在考察相思树种根瘤菌是否优良时,要综合考虑其侵染结瘤特性、对苗木生长的促进作用以及菌株的固氮酶活性及固氮量等因素.     

Patterns of exotic plant invasions in Pennsylvania’s Allegheny National Forest using intensive Forest Inventory and Analysis plots

Intensive Forest Inventory and Analysis (FIA) plot data collected in the Allegheny National Forest (ANF), Pennsylvania, between 1999 and 2006 were evaluated for their ability to predict ANF’s vulnerability to invasion by exotic plants. A total of 26 variables classified by biotic, abiotic, or disturbance characteristics were examined. Likelihood of colonization by invasive exotic and non-invasive exotic plants was analyzed using a logistic regression model. Approximately, 11% of the 449 species documented in these plots were exotic, which is higher than has been found in other northeastern forested plots. Only 1% of the ANF flora was invasive exotic plants and these were at low abundance, confirming that most invasions are still at an early stage of establishment. Sites richer in native or non-invasive exotic plants and with more alkaline soils were more likely to be invaded. Younger forests, forests with non-forest patches present, and forests rich in native species were more likely to be colonized by exotic (invasive or non-invasive) plants. Frangula alnus, which is starting to spread locally, differed from the other invasive exotic species in terms of its association with high sapling density to tree density ratios, high soil nitrogen levels, and the presence of fire. Variables representing mortality due to beech bark disease and distance to the nearest exotic planting manifested counterintuitive results. In both cases, the combined occurrence of mortality due to beech bark disease or a close (less than 500 m away) known propagule source and the presence of an invasive or non-invasive exotic plant was rare. We encourage increased use of intensive sampling for FIA in the U.S.A. and similar monitoring programs in other countries, but suggest adding a step to the plot selection phase that would allow forest-wide or regional stratified sampling of typically coarse-scale variables, such as historic or predicted defoliation or fire events, and forest or land type. A more accurate picture of the importance of disturbance variables in defining forest vulnerability to plant invasion may be achieved.     

Effect of rhizobial inoculations on nitrogen metabolism of Albizia lebbek seedlings

Rhizobia were isolated from Albizia lebbek (L) Benth. seed-lings collected from six different places, tested against the nodulation test and inoculated into 45 day old Albizia lebbek seedlings in steri...     

中国地被竹应用与引种栽培研究

地被竹是禾本科竹亚科中的低矮型竹类植物,在园林绿化中具有重要应用价值,还可作为固土护坡植物。文中在简述地被竹种类和主要特性的基础上,介绍了地被竹在园林造景、固岸防护和保健方面中的应用,以及生态适应性与引种栽培等方面的研究进展,展望了地被竹在园林中的应用前景和今后的研究重点,以期为我国地被竹进一步推广利用和引种栽培提供参考。