石斛气生的兰科菌根组织结构及其对御旱研究

基于过去对铁皮石斛(Dendrobium candidum Wall.Ex Lindl.)气生的兰科菌根适应干旱环境胁迫机理的研究鲜为涉及,现开展了培养基质的不同水分质量分数(w(水分)=43.6%、16.8%、5.5%)对兰科菌根的外部形态以及内部组织结构影响的研究。研究结果表明:基质水分质量分数降低使石斛菌根外部形态发生多样变化;随着基质水分质量分数的不断降低,石斛的生长受到显著的抑制。当基质水分质量分数为5.5%时,石斛的多数生长指标均小于其它处理,但是根冠比(R/S)增加显著,高达2.22;通过不同切片多重镜检测定和图像分析,发现菌根的形态结构产生了天然的适应突变,独特的根被组织细胞层数多达5层以上,细胞壁相对加厚,细胞腔内网、羽状结构比其它两处理明显增多,石斛菌根通过形态结构的改变来适应水分胁迫并维持其生长发育,石斛菌根组织结构的这些改变大大提高了石斛御旱的能力;水分质量分数高低与菌根感染率呈负相关,越是干旱条件菌根真菌繁衍越活跃,菌丝团结构相持时间越长,菌根的这些适应性响应都提高了石斛的抗旱能力。     

石斛气生的兰科菌根组织结构及其对御旱研究

基于过去对铁皮石斛（Dendrobium candidum Wall．Ex Lindl．）气生的兰科菌根适应干旱环境胁迫机理的研究鲜为涉及,现开展了培养基质的不同水分质量分数（W（水）1=43．6％、16．8％、5．5％）对兰科菌根的外部形态以及内部组织结构影响的研究。研究结果表明：基质水分质量分数降低使石斛菌根外部形态发生多样变化;随着基质水分质量分数的不断降低,石斛的生长受到显著的抑制。当基质水分质量分数为5．5％时,石斛的多数生长指标均小于其它处理,但是根冠比（R／S）增加显著,高达2．22;通过不同切片多重镜检测定和图像分析,发现菌根的形态结构产生了天然的适应突变,独特的根被组织细胞层数多达5层以上,细胞壁相对加厚,细胞腔内网、羽状结构比其它两处理明显增多,石斛菌根通过形态结构的改变来适应水分胁迫并维持其生长发育,石斛菌根组织结构的这些改变大大提高了石斛御旱的能力;水分质量分数高低与菌根感染率呈负相关,越是干旱条件菌根真菌繁衍越活跃,菌丝团结构相持时间越长,菌根的这些适应性响应都提高了石斛的抗旱能力。     

丛枝菌根对土壤-植物系统中重金属迁移转化的影响

丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)是一类在自然和农业生态系统中广泛存在并能与多数陆生植物形成共生关系的土壤真菌,在重金属污染土壤中对宿主植物的生长及吸收累积重金属具有重要影响,因而对污染土壤的生物修复具有潜在应用价值。以重金属从根际土壤进入植物并在植物体内再分配过程为主线,介绍丛枝菌根在这一过程中对重金属环境行为,特别是根际土壤中重金属赋存形态及植物吸收重金属的影响。最后,对丛枝菌根影响植物重金属耐性机制研究前沿和菌根修复技术的应用前景进行展望。     

菌根真菌对土壤有机污染物的生物降解

利用土壤真菌和植物的结合体菌根真菌修复土壤,尤其是修复有机污染的根际土壤.正作为一个新的研究方向开始受到广泛关注。菌根真菌作为土壤真菌的一种,与放线菌和细菌等微生物相比,对土壤中有机污染具有更大的忍耐能力.并且能将许多持久性有机污染物(POPs)做为碳源来获取能量。文章通过总结近20年菌根真菌与土壤有机污染物关系的研究,列出了43种能分解POPs的菌根真菌,并探讨了菌根真菌通过直接分解和共代谢的方式降解土壤有机污染物的可能性,为进一步研究菌根真菌生物降解土壤中持久性有机污染物,利用菌根植物生物修复有机污染土壤提供信息。     

VA菌根菌剂的生产及其接种潜力的测定

VA菌很是由球囊霉目的结合菌与植物根组织形成的一类共生联合体，在农林业生产中具有巨大的应用前景．众多研究表明，VA菌根真菌是一种亟待开发利用的微生物资源．本文详细介绍了VA菌根真菌的繁殖方法，探讨了VA菌根菌剂的生产途径；文中还讨论了测定菌剂接种潜力的评价方法，重点介绍了最或然数测定法．     

接种VA菌根对高粱吸收中、微量元素的影响

目前全球化肥消耗巨大，磷、钾资源短缺已日趋严重，生产氮肥要消耗大量的能源，而且，肥料利用率极低，浪费十分严重.因此，许多植物营养学家都在寻找其它的生物学途径，以求在保持作物产量进一步提高的前提下减少肥料的投入.例如，筛选和培育高营养效率的作物资源和微生物资源，培育非豆科植物的固氮菌，发掘解磷、解钾菌等.在这众多的生物学途径中，VA菌根菌则是其中的一种。VA（泡囊-丛枝Vesicular-arbuscular）菌根菌是一种对作物生长有益的天然真菌，它能和大多数陆生内在农作物形成共生关系.目前，大多数研究都集中在VA菌根菌对磷…     

丛枝菌根-植物修复重金属污染土壤研究中的热点

随着菌根研究和植物修复技术的发展,利用丛枝菌根强化重金属污染土壤的植物修复逐渐受到人们的重视。本文系统综述了当前的几个研究热点:(1)菌根植物吸收和转运重金属的分子机制;(2)AM真菌对超富集植物重金属吸收的影响及其机制;(3)AM真菌对转基因植物重金属吸收的影响及其机制;(4)AM真菌与其他土壤生物在植物修复中的复合作用;(5)丛枝菌根与化学螯合剂在植物修复中的复合作用;(6)重金属复合污染土壤的丛枝菌根-植物修复;(7)放射性污染土壤的枝菌根-植物修复;(8)丛枝菌根-植物修复的田间试验研究。在未来的丛枝菌根-植物修复研究中,要筛选优良的宿主植物和与之高效共生的AM真菌,加强相关理论和应用基础研究,并构建高效基因工程菌。     

丛枝菌根对盐胁迫的响应及其与宿主植物的互作

丛枝菌根真菌(Arbuscular Mycorrhizae Fungi,AMF)作为陆地生态系统的组成部分之一,在促进宿主植物对土壤养分和水分的吸收、提高植物生物量生产、调节种群和群落的结构、维持生态系统的稳定性等方面发挥了重要作用。其中,盐渍化是自然生态系统中广泛存在的一种胁迫生境条件,全球盐渍化土地约占耕地总面积的10%,因而探讨AM菌根在此胁迫生境下对宿主植物生长的影响具有重要意义。从以下几个方面,围绕盐胁迫条件、AM菌根和宿主植物三者之间的关系对当前国际上相关领域的研究进展进行了综述:1)AM真菌对盐胁迫的响应,包括菌根共生体形成、菌根侵染率、AM真菌的分布、菌丝体生长发育、孢子的形成和分布等;2)盐胁迫条件下AM菌根对宿主植物的效应,包括AM菌根促进宿主植物对P、N等元素的吸收、降低植物体内Na 的含量、提高光合作用能力,进而提高植物的生物量和对植物的群落结构产生影响等;3)AM菌根提高宿主植物耐盐性的机理,分别从植物根系形态的改变、水分吸收能力的加强、细胞内营养物质的平衡,以及细胞生理代谢的调节等方面对AM菌根促进植物抗盐性的机理进行了剖析。     

菌根技术在环境修复领域中的应用及展望

菌根作为植物根系和真菌所建立的共生体,是生物界最为广泛的一种互惠共生现象。这一系统的形成能够有效增强植物的物质生产和抗病能力,全面改善宿主植物的生长状况,因此在新兴生态农业生产领域受到广泛重视。与此同时,菌根系统的形成可有效促进植物对污染或胁迫环境的适应能力,以及对环境污染物的去除能力,并能联合其它根际微生物共同发挥效能,在受损和污染环境生态修复领域具有巨大的潜力。近年来,菌根技术在环境修复领域中的应用正成为环境工作者关注的新兴方向,但目前仍处于起步阶段。文章在前人研究结果的基础上,对菌根技术在重要的环境修复领域,如面源污染综合防治领域、污染场地生物修复领域、受损和胁迫环境恢复重建中的试验研究和应用进展进行了综述,并结合其发展现状探讨了当前菌根技术在环境修复治理工程应用以及大规模工业化生产中的瓶颈问题,提出应在菌根真菌对异质环境的适应性、菌根系统的复杂性解析、以及内生菌根真菌分离纯化等关键理论与技术方面加大力度,尽早实现广适性功能菌种的工业化生产和多元＂生物制剂＂的开发,从而在环境修复领域发挥更大的作用。     

菌根在污染土壤生物修复中的作用

菌根是土壤真菌 -植物根系形成的共生体 ,广泛存在于自然界中 ,它能增强植物的吸收能力 ,改善植物的生长 ,提高植株的抗逆能力和耐受能力等。所以 ,菌根化植物可作为很好的生物修复载体。本文主要从无机、有机以及放射性污染 3方面对国内外关于菌根在污染土壤生物修复中的作用进行了综述     

A Framework for Assessing Supply‐Side Wildlife Conservation

Market‐based, supply‐side interventions such as domestication, cultivation, and wildlife farming have been proposed as legal substitutes for wild‐collected plants and animals in the marketplace. Based on the literature, we devised a list of the conditions under which supply‐side interventions may yield positive conservation outcomes. We applied it to the trade of the orchid Rhynchostylis gigantea, a protected ornamental plant. We conducted a survey of R. gigantea at Jatujak Market in Bangkok, Thailand. Farmed (legal) and wild (illegal, protected) specimens of R. gigantea were sold side‐by‐side at market. These results suggest farmed specimens are not being substituted for wild plants in the marketplace. For any given set of physical plant characteristics (size, condition, flowers), the origin of the plants (wild vs. farmed) did not affect price. For all price classes, farmed plants were of superior quality to wild‐collected plants on the basis of most physical variables. These results suggest wild and farmed specimens represent parallel markets and may not be substitutable goods. Our results with R. gigantea highlight a range of explanations for why supply‐side interventions may lack effectiveness, for example, consumer preferences for wild‐collected products and low financial incentives for farming. Our results suggest that market‐based conservation strategies may not be effective by themselves and may be best utilized as supplements to regulation and education. This approach represents a broad, multidisciplinary evaluation of supply‐side interventions that can be applied to other plant and animal species. Un Marco de Referencia para Evaluar la Oferta de la Conservación de Vida Silvestre     

Epiphyte Biodiversity in the Coffee Agricultural Matrix: Canopy Stratification and Distance from Forest Fragments

Abstract: Quality of the agricultural matrix profoundly affects biodiversity and dispersal in agricultural areas. Vegetatively complex coffee agroecosystems maintain species richness at larger distances from the forest. Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species. We compared diversity, composition, and vertical stratification of epiphytes in a forest fragment and in two coffee farms differing in management intensity in southern Mexico. We also examined spatial distribution of epiphytes with respect to the forest fragment to examine quality of the two agricultural matrix types for epiphyte conservation. We sampled vascular epiphytes in a forest fragment, a shade polyculture farm, and a shade monoculture farm at 100 m, 200 m, and 400 m from the forest. Epiphyte and orchid richness was greater in the forest than in the monoculture but richness was similar in the forest and polyculture farm. Epiphyte species composition differed with habitat type, but not with distance from the forest. In the forest, epiphytes were distributed throughout tree canopies, but in the farms, epiphytes were primarily found on trunks and larger branches. Epiphyte richness and species similarity to forest species declined with distance from the forest fragment in the monoculture, but richness and similarity to forest species did not decline with distance from forest in the polyculture. This suggests polyculture coffee has greater conservation value. In contrast, monoculture coffee is likely a sink habitat for epiphytes dispersing from forests into coffee. Coffee farms differ from forests in terms of the habitat they provide and species composition, thus protecting forest fragments is essential for epiphyte conservation. Nonetheless, in agricultural landscapes, vegetatively complex coffee farms may contribute to conservation of epiphytes more than other agricultural land uses.     

Heterologous overexpression of Populus euphratica BAK1;1 gene enhanced resistance to Pst DC3000 in tobacco北大核心CSCD

BRI1-ASSOCIATED RECEPTORKINASE1(BAK1), a leucine-rich repeat (LRR) receptor protein kinase, plays a significant role in brassinosteroid (BR) signaling. Furthermore, it combines with other LRR-RLKs protein to initiate immune response in plants. The objective of this study was to (1) investigate the function of the Populus euphratica BAK1;1 gene in the resistance of transgenic tobacco to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and (2) discuss the regulation pathway of PeBAK1;1 involved in the resistance to plant pathogen. We cloned the cDNA sequence of the P. euphratica PeBAK1;1 gene, constructed the pBI121-35S::PeBAK1;1 over-expression vector, and then transformed it into wild-type tobacco by Agrobacterium-mediated transformation to obtain PeBA K 1;1-overexpressing transgenic tobacco plants. The bioinformatic analysis showed that the PeBAK1;1 protein contained all the structural features of the plant SERK family. The phylogenetic tree showed that PeBAK1;1 has the highest sequence homology with PtBAK1. The gene expression profile results indicated that the expression of PeBAK1;1 in the root was higher than that in the leaf and stem. The wild-type tobacco plants showed an obvious susceptibility to Pst DC3000, whereas the transgenic plants exhibited enhanced resistance to Pst DC3000. Compared with that of the wild-type (WT), the real-time PCR and quantitative real-time PCR analysis revealed that the expression of pathogenesis-related genes (including PR1, PR3, PR4, and PR5), BAK1-interacting receptor kinase 1 gene, and BONZAI1 gene was upregulated in 35S::PeBAK1;1 transgenic tobacco plants. In conclusion, the PeBAK1;1 gene plays a positive regulatory role in 35S::PeBAK1;1 transgenic tobacco against Pst DC3000, which can enhance the resistance of plants to pathogen. © 2018 Science Press. All rights reserved.     

新垦赤红壤不同轮作的养分变化

五年的研究结果是:赤红壤耕垦之后只要采取合理的轮作和结合适当的秸秆返回措施,它的肥力就可以得到保持,而且还可以获得显著提高。在四种轮作形式中,效果最明显的为1:1,它的土壤有机质、全量N、P、K含量比轮作前分别提高了L 22、1.84、2.27和0.06倍1:2和2:1的效果较差,分别提高了0.57、0.83、2.08、0.39倍和1.02、0.91、1.46、-0.07倍,0:1的由于没有轮作,加上每年把长好的草皮铲走,导致了土壤有机质、全氮量反而比轮作前下降了6.5％和25.0％。随着轮作土壤养分的提高,土壤物理和微生物状况也获得了改善。     

AzaC预处理增加TCDD对特殊细胞P450基因的诱导

利用RT-PCR检测不同物质诱导细胞的CYP基因 mRNA的表达水平.在HepG2细胞,TCDD能诱导CYP1A1、CYP1B1及CYP1A2基因表达,CYP1A1、CYP1B1基因比CYP1A2基因更容易被诱导,用AzaC处理后CYP1B1基因表达无改变;在A549细胞和SPC-A1细胞,Azac预处理后增加了TCDD对CYP1家族的诱导.也就是AzaC增加了CYP1A1、CYP1A2和CYP1B1基因表达水平.图1表1参10     

Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr~(6+)和Mn~(2+)对萼花臂尾轮虫联合急性毒性研究

为探究重金属复合污染对轮虫的毒性影响,以萼花臂尾轮虫为受试动物,选择Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr6+和Mn~(2+)等5种重金属,采用水生毒理联合效应相加指数法开展了其24 h联合急性毒性作用的评价研究。结果显示,Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr6+和Mn~(2+)等5种重金属对萼花臂尾轮虫24 h半数致死浓度分别为:0.00616 mg·L~(-1),12.62 mg·L-1,2.89 mg·L-1,17.29 mg·L-1和67.32 mg·L-1。联合急性毒性实验结果显示,等毒性配比的Cu~(2+)-Cr6+(0.00385-10.806 mg·L-1)和等浓度配比的Cu~(2+)-Zn~(2+)(0.0199-0.0199 mg·L-1)、Cu~(2+)-Cd~(2+)(0.0181-0.0181 mg·L-1)、Cu~(2+)-Cr6+(0.0118-0.0118 mg·L~(-1))、Zn~(2+)-Cd~(2+)(3.475-3.475 mg·L-1)二元联合测试液的作用结果显示为拮抗效应,其余二元联合测试液的作用结果则均显示是协同效应。等毒性配比的Cu~(2+)-Cr~(6+)-Mn~(2+)(0.00210-5.902-22.981 mg·L-1)和等浓度配比的Cu~(2+)-Cd~(2+)-Mn~(2+)(0.00727-0.00727-0.00727 mg·L-1)三元联合测试液的作用结果显示为拮抗效应,其余三元联合测试液的作用结果则均显示是协同效应。等浓度配比的Cu~(2+)-Zn~(2+)-Cd~(2+)-Cr6+(0.00907-0.00907-0.00907-0.00907 mg·L-1)、Cu~(2+)-Zn~(2+)-Cd~(2+)-Mn~(2+)(0.00898-0.00898-0.00898-0.00898 mg·L~(-1))、Cu~(2+)-Zn~(2+)-Cr6+-Mn~(2+)(0.00819-0.00819-0.00819-0.00819 mg·L~(-1))四元联合测试液的作用结果显示为拮抗效应,其余四元联合测试液的作用结果的则均显示是协同效应。Cu~(2+)-Zn~(2+)-Cd~(2+)-Cr~(6+)-Mn~(2+)等毒性(0.00074-1.520-0.348-2.082-8.107 mg·L~(-1))和等浓度(0.00582-0.00582-0.00582-0.00582-0.00582 mg·L-1)配比的五元联合测试液作用结果均显示是协同效应。     

Cloning and expression analysis of ScBAK1 gene and its alternative spliceosome in sugarcane北大核心CSCD

Alternative splicing (AS) is an important part of regulation of eukaryotic gene expression. BAK1 (Brassinosteroid insensitive1-associated receptor kinase 1) is a specific type of plant serine/threonine protein kinases, and can regulate growth and development and natural immunization. To reveal the responses of sugarcane BAK1 gene to the adverse environment, a ScBAK1 gene and its alternative spliceosome, termed ScBAK1 (GenBank accession number: KP032226) and ScBAK1 S1 (GenBank accession number: KP032227), were cloned from leaf cDNA of Yacheng 05-179 utilizing the methods of electronic cloning and RT-PCR. The open reading frame (ORF) length of ScBAK1/ScBAK1 S1 gene was 1 860bp/1 770bp, encoding 619/589 amino acids residues. The predicted molecular weight of the protein was 69.28 kDa/ 65.76 kDa. Both proteins were located in plasma membrane, estimated as acid, hydrophikic and secretive proteins. Random coil and alpha helix gave priority to extended strand in their secondary structure without beta turn. The most important protein function was cell envelope, secondly biosynthesis of amino acids and cofactors. Real-time quantitative PCR analysis revealed that the expression of sugarcane ScBAK1 S1 gene exhibited the reduced expression trend under smut fungus stress and various abiotic exogenous stresses, including SA, CuCl2, PEG, ABA, NaCl and JA, while the expression of ScBAK1 gene was induced by SA, CuCl2, PEG, NaCl and smut fungus stresses. The phenomenon showed that the absent sequences or amounts of ScBAK1 S1 gene plays a key role in the response of ScBAK1 to the stress of sugarcane smut fungus, osmotic stress and cell growth. The differential expression of ScBAK1 and ScBAK1 S1 lays a foundation for further research on the function of ScBAK1 gene under biotic and abiotic stress.     

苏云金芽孢杆菌新基因cry1Ab17的克隆和生物信息学

利用高效克隆PCR产物的专用载体pMD18T,直接从苏云金芽孢杆菌WB9的PCR产物中克隆了cry1Ab17新基因.测序结果表明,该基因(GenBank登录号为AY646166)由3471个碱基组成,其编码的蛋白质含有1156个氨基酸残基,其中亲水性氨基酸占30.8%,疏水性氨基酸占45.2%,酸性氨基酸占12.9%,碱性氨基酸占11.1%.氨基酸序列的同源性分析结果表明,Cry1Ab17蛋白与已报道的Cry1Ab蛋白同源性为95.4%～99.7%,该蛋白的4个氨基酸残基———Pro170、Gly449、Gly796和Gly863与其它已报道Cry1Ab蛋白相应位置的氨基酸残基均不同.在核苷酸序列和氨基酸序列多重比较的基础上,应用PAUP4.0构建了Cry1A蛋白家族的系统发育树.SignalP分析结果显示,Cry1Ab17蛋白中不含信号肽序列.此外,对Cry1Ab17蛋白的二级结构和3个结构域也进行了预测和分析.图4表2参15     

节杆菌P-1和红球菌J-5降解PVA特性的比较研究

对节杆菌P-1和红球菌J-5降解聚乙烯醇(PVA)的特性进行了比较研究.结果表明,P-1菌在PVA浓度小于1000mgL-1时,PVA降解效率均达到80%以上;J-5菌在PVA浓度为2000mgL-1时,PVA降解效率达到70%.用生产废水进行试验,P-1菌对低浓度PVA废水的处理效率比J-5菌高10%左右;P-1菌受温度的影响小于J-5菌;P-1菌的废水处理效果比J-5菌稳定;分段使用J-5菌与P-1菌处理高浓度的PVA废水具有很好的处理效果,出水能达到国家排放标准.图7表1参9     

鱼类镰刀菌的研究Ⅲ：几种药物对鱼类镰刀菌的抑制作用

研究发现制霉素（14．4～16．0mg·L－1）、K制剂（4．0mp·L－1）和孔雀绿（3,0～40mp·L-1）对镰刀菌Fu2和尖F1抑制效果好,而对Fu1-2抑制效果差;优氯净（2．0mg·L－1）能抑制Fu1-2,而不抑制Fu2和尖F1;龙胆紫（1．0mg·L-1）可抑制尖F1,而不抑制Fu2和Fu1-2制霉素对鱼毒性最小,而孔雀绿毒性最大．