白腐真菌对染料的脱色与降解

利用白腐真菌对染料脱色和降解的过程机理及影响因素进行了较为系统的介绍,结果认为,白腐真菌对染料的脱色及降解作用可能主要是由于其在次生代谢阶段产生的木质素过氧化酶LIPs和锰过氧化酶MnPs所致。在培养基中加入黎芦醇等能够显著提高LIPs的产生;富氮培养基会抑制LIPs的生成;缓冲液的选择对维持适宜的pH值和菌丝的形态有一定作用,从而影响其脱色效果;富氧环境是一切白腐真菌对染料进行脱色和降解的必要条件;适度的搅拌混合有利于反应时的物质之间传递;一般地,在培养时间达到3d以后白腐真菌才能达到较高的脱色与降解活性。染料分子大小和结构及其基团的位置对脱色及降解效果有明显影响。使用特殊填料来提高处理系统中的生物量以克服真菌生长速度相对较慢,提高处理能力是该技术今后的研究重点。     

Effect of some technical and formulated insecticides on microbial activities in soil

Abstract

The influence of 11 formulated and technical insecticides at 10 μg/g soil on growth and activities of microorganisms was determined. The populations of bacteria and fungi initially decreased with some pesticide treatments but recovered rapidly to levels similar to or greater than those of controls after three weeks. Both formulated and technical chlordane, chlorpyrifos and cypermethrin stimulated fungal growth. No inhibition on nitrification after two wks and sulfur oxidation after three wks was observed in treatments with either grade of insecticide. The effect of different treatments on respiration was equal to or greater than that of control sample. Less effect was observed with technical insecticides than the formulated ones on microbial populations and activities in the soil.     

Mycogenic decomposition of wood and carbon emission in forest ecosystems

Problems related to biological decomposition of wood and volumes of mycogenic emission of carbon dioxide and carbon in forests of Western Siberia are considered. Annual C-CO₂ emission in the region reaches 31 million tons of carbon, which is equivalent to 116 million tons of carbon dioxide. With respect to the volume of emission, natural zones may be arranged in the following descending series: southern taiga (38%), middle taiga (29%), subtaiga (16%), forest-steppe (10%), northern taiga (6%), and forest-tundra (1%).     

北京市室外空气真菌分布特征

通过定点取样研究北京市空气真菌的种类组成,浓度特征及其动态变化规律.监测结果表明,北京市空气真菌平均浓度为(1164.8±73.2)CFU.m^-3,浓度变异很大,变化范围为23.6～13959.5CFU.m^-3.空气中优势真菌为枝孢属(Cladosporium)、青霉属(Penicillium)、链格孢属(Alternaria)、曲霉属(Aspergillus)和无孢菌(non-sporing),其中枝孢属是绝对优势真菌,浓度约占真菌总浓度的1/3以上.文教区和公园绿地空气真菌浓度夏季和秋季较高,春季和秋季较低,而交通干线空气真菌浓度4季变化趋势不明显.文教区和公园绿地空气真菌浓度明显高于交通干线(p<0.05),文教区和公园绿地之间则没有显著差异.     

Composition of the Saprotrophic Fungi in Calluna Heathland Soil and the Influence of Ammonium Nitrate Application

The composition of saprotrophic soil fungi in the mor layerof a Calluna-dominated, Danish heathland wasinvestigated after two years of fertilization with ammoniumnitrate (0, 35, 50 and 70 kg N ha^1- yr^-1) using asoil washing technique. The most frequently isolated generafrom the soil particles plated were Penicillium, Trichoderma, Mortierella and Mucor. Eightspecies of Penicillium were identified and Penicillium spinulosum was the most frequently isolated.The occurrence of dark, sterile fungi on the soil particleswas low. There were no measurable changes in the specificcomposition of the saprotrophic soil fungal groups due tothe nitrogen treatments, beside from an increasedoccurrence of Absidia californica. I conclude that adirect impact on the composition of the saprotrophic fungiin heathland soil is unlikely under enhanced nitrogen input.     

菌根类型对森林树木净初级生产力的影响

菌根是土壤真菌与植物根系形成的共生体,存在于绝大多数植物（90%）的根系和生境中。菌根共有7种类型,在生态系统的过程和功能方面都扮演着十分重要的角色。为了增强对菌根在森林生态系统中重要功能的理解,文章基于全球森林数据库,在全球尺度上研究了不同菌根类型对森林树木净初级生产力（NPP）的影响。结果表明,森林树木NPP随菌根类型的不同而不同,AM类型菌根森林的NPP[679.49 g.m-2.a-1（以C计）]要显著高于含ECM类型菌根的森林[479.00 g.m-2.a-1（以C计）];菌根类型的不同对森林树木地上和地下及其各组分NPP的影响和贡献也存在着显著的不同,AM类型菌根对地下NPP的贡献要高于ECM菌根,而ECM菌根对地上NPP的贡献则较大。菌根类型对地上、地下NPP组分的影响分析则表明,AM类型的菌根对树叶和细根NPP的贡献较大,而ECM类型菌根则对树木主干和枝NPP的贡献较大。可见,森林树木总体NPP及其各组分NPP都随着菌根类型的不同而存在显著的差异。     

桦木内生真菌的分离与代谢产物的抑菌活性

通过琼脂块法和滤纸片法,对白桦Betula platyphylla、棘皮桦B.dahurica、硕桦B.costata和柴桦B.fruticosa）的内生真菌产生抑菌物质的特性进行研究,结果表明分离自白桦3年生枝条的内生真菌拟茎点霉Phomopsis sp.BP103381表现出较强的抑菌物质形成能力。采用正交设计优化了BP103381的培养条件,在含有40 g/L蔗糖、3 g/L NaNO3、1 g/LMgSO4的改良查氏液体培养基中,在pH值6.5、28℃条件下发酵培养9 d,有利于抑菌活性物质的形成。BP103381产生的抑菌活性物质具有较好的温度稳定性,但是酸碱变化对抑菌物质的活性影响较大,BP103381产生的抑菌物质在pH为5.0~7.0时活性较强。     

白腐真菌酶学与分子生物学研究进展

白腐真菌对木质素降解的特异性生物学机制显示出其在复杂有机污染物降解中具有潜在应用前景。对白腐真菌酶学、自由基化学及分子生物学的国内外研究情况进行了较全面的介绍,以供国内同行参考。     

AM真菌对烟草砷吸收及根际pH的影响

采用矿区3种砷(As)含量土壤水提液的琼脂培养基变色试验,研究接种土著(Glomus spp.,Acaulospora spp.)与外源(Glomus caledonium)AM真菌对煳草(Nicotiana tabacum L.)As吸收以及根际pH的影响.结果表明,除无As水平下的烟草对照苗根际pH持续升高外,其它处理的烟草化苗根际pH都有先升高后降低的规律,而且菌根化苗根际pH的降低速度快于对照苗.烟草地上部分As含量在所有处理中没有表现出显著的差异.在无As水平下,烟草地下部分As含量依次为外源菌根化苗>土著菌根化苗>对照苗.在低As、中As、高As水平下,土著菌根化苗的地下部分As含量显著高于外源菌根化苗以及对照苗.可见,接种AM真菌可以降低烟草根际pH,从而影响烟草的As吸收,这也显示了AM真菌应用于烟草安全的可能性.此外,本研究表明土著AM真菌与外源AM真菌对培养基质中的同一As水平有着不同的响应.     

Effects of Arbuscular mycorrhizal fungi isolated from white clovers (Trifolium repens L) on soil bacteria and fungi

White clover potted experiments were performed to investigate the effects of seven indigenous arbuscular mycorrhizal fungi (AMF) communities isolated from different test plots subjected to long-term fertilisation on soil enzyme activities, number of soil bacteria and fungi. The results showed that the inoculation of arbuscular mycorrhizal fungi communities increased the mycorrhizal infection rate of the plants and promoted the growth of plants. The Mnp treatment was most effective. The shoot biomass, root biomass, potassium and nitrogen uptake of the white clover in Mnp treatment group were increased by 61.54%, 84.00%, 62.50% and 46.71% respectively, compared with those in non-inoculation treatment. The inoculation of AMF communities had little effect on the number of bacteria in the soil, but significantly increased the number of soil fungi. Mnk treatment group had the highest number of fungi in the soil, which was 9.91 times that of the non-inoculation treatment group. The catalase and dehydrogenase activities were both significantly improved in Mnp treatment by 28.12% and 205.38% respectively, compared with those of the control treatment (-M). The urease, invertase and cellulase activities reached the highest levels in the Mck treatment; they were increased by 142.79%, 41.17% and 77.62% respectively, compared with those of the control treatment. Pearson correlation analysis showed that the soil enzyme activity was not correlated with the mycorrhizal infection rate, but correlated with the spore number of the AMF community. The impact of AMF community on soil quality is important for us to understand the function of the ecosystems. Relevant study provides important guidance for maintaining the balance of the soil-plant system and the development of sustainable agriculture.