丛枝菌根根外菌丝对铵态氮和硝态氮吸收能力的比较

采用空气隔板分室法并结合15N标记技术,以玉米为宿主植物并接种Glomus mosseae和Glomus intraradices,比较了这两种真菌根外菌丝对铵态氮和硝态氮吸收传递能力的差异。结果表明,丛枝菌根根外菌丝吸收传递氮的能力因菌种和氮素形态而异。两种真菌根外菌丝吸收传递NH4+-N能力均高于NO3--N;G. intraradices根外菌丝吸收传递氮的能力高于G. mosseae,这可能与两种真菌根外菌丝生长量有关。     

AM菌丝在2种培养基质中的生长状况比较

菌丝是丛枝菌根吸收传递养分的主要部分,传统采用玻璃珠培养收集菌丝法,虽然可以收集到纯净的AM菌丝,但收集到的菌丝量较少。以玉米为宿主植物,以单用玻璃珠(对照)或以玻璃珠(2 mm)与沙子(0.25~1.00 mm)混合作为培养基质,分别接种Glomus mosseae或Glomus intraradics进行AM菌丝收集。结果表明,接种G. mosseae的植株根系侵染率显著低于G. intraradics处理,而收集到的G. mosseae根外菌丝量却显著高于G. intraradics。玻璃珠和沙子混合培养基质收集到的G. mosseae根外菌丝干重可达24.4 mg/kg,约为玻璃珠基质的4.7倍。     

丛枝菌根真菌对西藏高原草地植物和土壤环境的影响

采用三室隔网装置，就Glomus etunicatum、Glomus intraradices、Glomus mossecte对2种高山草地植物和土壤环境的影响进行了研究。结果表明：（1）接种AM真菌对草地植物的侵染和生长均具显著效应，植株地上部、根系干物重以及含磷量、吸磷量均显著高于不接种处理，菌根菌丝对植株吸磷的贡献率达47.8％-69．5％。其中，Glomus intraradices、Glomus mosseae分别对穗序剪股颖、紫羊毛吸收土壤磷索更具促进作用。（2）各接种处理中室土壤中各类微生物数量均显著高于边室土壤，但边室土壤中放线菌，特别是细菌、真菌的平均增幅均远高于中室土壤，表明菌根际、菌丝际土壤中各类微生物的数量差异趋于明显缩小，微生物区系构成得以平衡与改善；解磷细菌（芽孢杆菌）亦呈同一趋势。（3）2—1 mm粒径团聚体在土壤水稳性团聚体构成中占有绝对比重，菌根菌丝对距根表不同距离处2—1 mm团聚体形成的贡献率均在70％以上，但距根表2—4cm处菌根菌丝贡献率明显低于0-2、4-6cm处，并未表现出随菌丝密度增加而提高的趋势；5—2mm水稳性团聚体仅距根表较远处有少量形成（菌丝贡献率达100％），0-2、2—4cm处则未见分布。（4）同一、不同AM真菌对不同或同一草地植物的侵染及所产生的菌根效应具有不同程度的差异，穗序剪股颖各接种处理普遍优于紫羊毛，紫羊毛＋Glomus mosseae、穗序剪股颖＋Glomus intraradices优于同组其他接种处理的趋势较为明显。     

丛枝菌根真菌对羊草气体交换和δ~(13)C、δ~(15)N的组成影响

采用盆栽方法研究接种两种丛枝菌根真菌Glomus intraradices,Glomus claroidum对内蒙古典型草原优势种羊草(Leymus chinensis)的气体交换和稳定性同位素组成的影响,对羊草生长第45、60和75天的测定结果表明,丛枝菌根真菌能提高植株的含磷量、叶片的气孔导度和光合速率,降低植株δ15N值,但对羊草的内在水分利用效率和δ13C的组成未产生显著影响;植株生长的不同时期对其气体交换和稳定性同位素δ13C、δ15N均产生显著影响;时间和接种的相互作用显著影响植株的光合速率、δ13C和δ15N;羊草气孔导度和光合速率的提高归因于菌根真菌改善植株磷营养和增加根系碳分配所致;而植株内在水分利用效率和δ13C无显著性差异是因为气孔导度和光合速率总是发生同方向变化造成的;菌根植物具有较低δ15N是源于菌根真菌吸收N,并富集15N,转运给植株贫化的15N所致。试验结果为认识草原植物的碳水平衡和N循环提供了新的思路和借鉴。     

接种丛枝菌根真菌对玉米秸秆降解的影响

为研究接种丛枝菌根真菌(AMF)对玉米秸秆降解的影响,利用玉米秸秆为材料制成网袋,采用盆栽试验,以玉米(Zea mays L.)为宿主植物,分别接种Glomus intraradices和Glomus mosseae,于30,40,50,60d时收获后分析玉米秸秆降解量和C、N释放量,并运用Olson的指数模型Bt/B0=e-kt计算玉米秸秆及C、N的降解系数。数据表明,接种G.intraradices、G.mosseae显著提高了玉米秸秆降解量和降解系数,与不接种处理相比,分别高出5.21%,6.26%。C释放量、碳素降解系数也明显增加。接种处理减少了N释放量,且氮素降解系数随时间延长而下降。接种处理玉米秸秆的C、N降解系数不同直接反映了其降解速度的差异,进而影响了玉米秸秆的C/N,使秸秆更易于降解。研究结果显示出丛枝菌根真菌在生态系统氮循环中具有重要意义。     

外源磷与AMF对间作玉米种植红壤无机磷形态的影响

通过三室隔网分室盆栽模拟试验,研究了分室不同磷(P)源[无机磷(磷酸二氢钾)和有机磷(大豆卵磷脂),P添加量均为50 mg·kg-1]添加和根室接种不同丛枝菌根真菌(AMF)[Glomus mosseae(GM)、Glomus etunicatum(GE)]对间作玉米种植红壤无机磷形态的影响。结果表明:无论接种与否,间作处理使根室土壤有效磷含量显著降低,说明间作能够促进玉米植株对土壤有效磷的吸收,且有效磷的耗竭从根际土壤开始。除OP50-单作玉米处理的Org-P外,接种AMF均一定程度增加了各形态无机磷含量。此外,根室土壤有效磷的主要组分为Ca2-P、Al-P和Org-P,其中Org-P与土壤有效磷有着极显著的负相关关系。     

接种丛枝菌根真菌对土壤水稳性团聚体特征的影响

为了研究接种丛枝菌根真菌对土壤团聚体特征的影响,采用盆栽试验,以小麦(Triticum aestivuml)为宿主植物,在两个不同供磷水平条件下,分别接种丛枝菌根真菌Glomus intraradices和Glomus mosseae,收获后分析土壤团聚体数量、分布和分形维数,并运用通径分析对不同作用因子进行统计。结果看出,与对照相比,接种丛枝菌根真菌显著提高了土壤中有机质含量、球囊霉素相关土壤蛋白含量,土壤水稳性大团聚体数量也显著增加。接种处理提高了土壤的平均重量直径、几何平均直径,而且降低了土壤分形维数。通径分析表明,在影响土壤水稳性大团聚体的众多因子中,菌丝密度具有最大的作用,且以直接作用为主;有机质和球囊霉素相关土壤蛋白也表现出较大的作用。接种G. mosseae对改良土壤结构的作用优于接种G. intraradices。     

丛枝菌根真菌对西藏高原固沙植物吸磷效率的影响

采用盆栽方法,就外源菌种、土著菌种(含混合菌种)对固沙植物白草(Pennisetum.flaccidum)生长和吸磷效率的影响进行了研究。结果表明,白草具有较高的菌根依赖性(平均达166.4%);不同AM真菌(或真菌组合)对白草根系均具显著的侵染效应。随菌根侵染率的提高,植株生物量、吸磷量均呈显著增加(相关系数分别为0.7465*、0.6000*);菌根菌丝对白草吸收土壤磷素的贡献十分明显,各接种处理菌根菌丝对植物吸收土壤磷素的贡献量、贡献率分别在3.2～11.6.mg/pot和61.5%～85.3%之间;接种菌根处理植株吸磷量呈Glomus.intraradicesG.mosseae+G.etunicatum+G.intraradices+Scutellospora.erythropaG.mosseae(外源菌种)G.mosseae+G.intraradices+Scutellospora.calosporaG.mosseae-I(土著菌种)G.etunicatum的趋势。此外,不同AM真菌对寄主植物地上部、根部生物量和吸磷量的影响程度明显不同,一般呈地上部根系的趋势,但寄主植物根系的生长速率相对较快;土著菌种中,多菌混合接种对寄主植物的侵染效应明显高于单一接种。     

分根装置中接种AMF对12 mm土壤水稳性团聚体的影响

采用分根装置研究了丛枝菌根真菌侵染白三叶草（Trifolium repens）后对中性紫色土12 mm土壤水稳性团聚体（WSA1-2mm）含量的影响,并运用通径分析对其主要影响因子进行了量化比较。结果表明,接种Glomus intraradices、G. mosseae和G. etunicatum的菌根室土壤有机质、球囊霉素相关土壤蛋白（GRSP）含量均有增加的趋势; 接种3种菌种都显著增加了菌根室土壤WSA1-2mm含量。通径分析结果表明,菌丝密度对WSA1-2mm含量有较大的直接效应（直接通径系数 0.678）,而GRSP对WSA1-2mm的影响系数较小,既有直接效应又有间接效应,但以直接效应为主。菌丝和GRSP对12mm 土壤水稳性团聚体作用大小的差异可能源于二者作用机制的不同。     

AM菌对三叶草吸收、累积重金属的影响

采用4室根箱培养系统,探讨了Cu、Zn、Pb、Cd 4种重金属复合污染土壤中,丛枝菌根菌对三叶草生长及吸收、累积重金属的作用,结果表明:重金属Cu 100mg/kg、Zn 600mg/kg、Pb 300mg/kg、Cd 10mg/kg的复合污染对三叶草生物量影响较小,但土壤重金属处理使丛枝菌根菌Glomus intraradices和Glomus caledonium对三叶草的侵染率分别降低53%和56%,菌种G.intraradice的菌丝密度降低73%;接种菌根真菌能明显减少重金属复合污染土壤中三叶草对Cu、Cd和Pb的吸收,并强化根系在限制重金属Pb和Cd向地上部运输中的作用,地上部Pb和Cd含量分别下降24.2%~55.3%和65%~97.9%,使三叶草地上部Cd和Pb含量均低于我国牧草重金属安全含量,提高了三叶草可食部分的质量;不同菌根真菌对三叶草吸收、累积及分配重金属的影响有明显差异,Glomus intraradices对减少三叶草对重金属的吸收及其在地上部可食部分的累积的作用大于Glomus caledonium。丛枝菌根菌对于强化三叶草根系对重金属的固持作用,调节生态系统中重金属的生物循环,减轻重金属对食物链的污染风险方面起着重要作用。     

Effect of Syrian Indigenous Arbuscular Mycorrhizal Fungi in Combination with Manure on the Growth of Cotton (Gossypium hirsutum L.)

A pot experiment was conducted to evaluate the effect of indigenous arbuscular mycorrhizal fungi (AMF) and the synergy of indigenous AMF and sheep manure (SM) on cotton growth and nitrogen and phosphorus uptake. AMF were a mixture of Glomus viscosum, Glomus mosseae, and Glomus intraradices initially isolated from a Syrian cotton field. Dry biomass was enhanced significantly by AMF and was higher at AMF plus SM treatment compared to control. Cotton plants showed a significant dependency to indigenous AMF, which was 52% in the AMF treatment. Plant concentrations of nitrogen (N)and phosphorus (P) were significantly higher in mycorrhizal than nonmycorrhizal plants. Maximum plant N and P uptake was found in the treatment of AMF inoculation with SM, which was significantly higher by 202% and 397% over control, respectively. Indigenous AMF was successful in colonizing cotton roots and when combined with SM resulted in better plant growth and N and P uptake.     

丛枝菌根真菌对万寿菊生长、吸镉及生理特性的影响

A pot experiment was carried out to study the effects of three arbuscular mycorrhizal fungi (AMF), including Glomus intraradices, Glomus constrictum and Glomus mosseae, on the growth, root colonization and Cd accumulation of marigold (Tagetes erecta L.) at Cd addition levels of 0, 5 and 50 mg kg-1 in soil. The physiological characteristics, such as chlorophyll content, soluble sugar content, soluble protein content and antioxidant enzyme activity, of Tagetes erecta L. were also investigated. The symbiotic relationship between the marigold plant and arbuscular mycorrhizal fungi was well established under Cd stress. The symbiotic relationship was reffected by the better physiobiochemical parameters of the marigold plants inoculated with the three AMF isolates where the colonization rates in the roots were between 34.3% and 88.8%. Compared with the non-inoculated marigold plants, the shoot and root biomass of the inoculated marigold plants increased by 15.2%- 47.5% and 47.8%-130.1%, respectively, and the Cd concentration and accumulation decreased. The chlorophyll and soluble sugar contents in the mycorrhizal marigold plants increased with Cd addition, indicating that AMF inoculation helped the marigold plants to grow by resisting Cd stress. The antioxidant enzymes reacted differently with the three AMF under Cd stress. For plants inoculated with G. constrictum and G. mosseae, the activities of superoxide dismutase (SOD) and catalase (CAT) increased with increasing Cd addition, but peroxidase (POD) activity decreased with increasing Cd addition. For plants inoculated with G. intraradices, three of the antioxidant enzyme activities were significantly decreased at high levels of Cd addition. Overall, the activities of the three antioxidant enzymes in the plants inoculated with AMF were higher than those of the plants without AMF inoculation under Cd stress. Our results support the view that antioxidant enzymes have a great influence on the biomass of plants, and AMF can improve the capability of reactive oxygen species (ROS) scavenging and reduce Cd concentration in plants to alleviate Tagetes erecta L. from Cd stress.     

丛枝菌根真菌对紫花苜蓿吸收土壤中镉和锌的影响

采用温室盆栽试验方法,研究了镉（Cd）、锌（Zn）污染土壤中,8种不同丛枝菌根真菌（AMF）Glomus lamellosum（G.la）、Acaulospora mellea（A.m）、Glomus mosseae（G.m）、Glomus intraradices（G.i）、Glomus etunicatum（G.e）、Glomus constrictum（G.c）、Diversispora spurcum（D.s）、Glomus aggregatum（G.a）对紫花苜蓿（Medicagosativa L.）吸收Cd、Zn的影响。结果表明,Cd、Zn污染下AMF仍然明显侵染紫花苜蓿,并促进紫花苜蓿对Cd、Zn的吸收积累,但不同AMF影响的效应和植株不同部位对重金属的吸收积累规律存在差异。AMF处理下紫花苜蓿根部Cd、Zn含量和积累量明显增加,但地上部Cd、Zn的含量则降低,地上部Zn的积累量也减小,这表明AMF处理减弱了Cd、Zn由根部向地上部的运移,减轻了植物地上部毒害。接种AMF条件下,植株尤其是根部生物量增加是Cd、Zn在其体内含量和积累量增加的重要因素,不同种类AMF促进植株生物量增加的幅度不同,导致植株对Cd、Zn的积累和抗性存在差异。     

丛枝菌根真菌侵染对紫色土水稳性团聚体特征的影响

为了研究接种丛枝菌根真菌对土壤团聚体特征的影响,采用盆栽试验,以白三叶草(Trifolium pratense)为宿主植物,在两不同供磷水平条件下,分别接种丛枝菌根真菌Glomus intraradices和Glomus mosseae,收获后分析土壤团聚体数量、分布和分形维数,并运用通径分析对不同作用因子进行统计。结果表明:与对照相比,接种丛枝菌根真菌显著提高了球囊霉素相关的土壤蛋白含量,土壤水稳性大团聚体数量也显著增加。接种处理提高了土壤的平均重量直径,几何平均直径,而且降低了土壤分形维数。通径分析表明,在影响土壤水稳性大团聚体的众多因子中,菌丝密度具有最大的作用,且以直接作用为主,球囊霉素相关土壤蛋白也表现出较大的作用系数,但以间接作用为主。同时接种的两种菌种表现出对土壤结构改良作用大小的不同,在实际运用中需要考虑到此点。     

不同氮素形态比例条件下接种AMF对玉米氮同化关键酶的影响

以珍珠岩为基质,通过供应3种不同的NH4+∶NO3ˉ比例营养液,研究了接种丛枝菌根真菌对玉米氮同化关键酶活性的影响。结果看出,与不接种的玉米植株相比,接种Glomus intraradices和Glomus mosseae分别在NH4+∶NO3ˉ=3∶1和NH4+∶NO3ˉ=1∶3形态下提高了植物叶片的硝酸还原酶活性;接种AMF对叶片谷氨酰胺合成酶活性（GS）影响不大,但在NH4+∶NO3ˉ=3∶1形态下接种3种AMF处理均显著提高了根系GS活性,相对提高了铵态氮在地下部的同化比例。在铵态氮比例较高时,接种AMF的促生效应较好,且AMF提高根系GS活性作用较大。表明丛枝菌根真菌在促进宿主植物对铵态氮的利用作用较大。     

Interactive effects of co-inoculation of Bradyrhizobium japonicum strains and mycorrhiza species on soybean growth and nutrient contents in plant

The main objective of this study was to investigate the effects of co-inoculation with different strains of Bradyrhizobium japonicum (i.e. Helinitro, Rizoking, and Nitragin) and arbuscular mycorrhizal fungi (AMF) species (i.e. Glomus fasciculatum, Glomus versiforme, Glomus intraradices, Glomus mosseae, and Glomus etunicatum) on soybean growth, fungal root colonization, and nutrient uptake of nitrogen (N), phosphorus (P), zinc (Zn), iron (Fe), and copper (Cu). Co-inoculation with various AMF species and rhizobia significantly (p<0.01) increased the soybean biomass production as compared to the non-inoculated controls. Furthermore, AMF colonization of roots of soybean plants increased by 79, 70.1, 67, 63, 57.5, and 50.1% in the presence of G. fasciculatum (GF), G. versiforme (GV), G. intraradices (GI), G. mosseae (GM), and G. etunicatum (GE), and Gmix (a mixed culture of fungi), respectively. Higher nutrient contents were observed in plants co-inoculated with Helinitro and GF. More insight into these results will enable optimization of the effective use of AM fungi in combination with their bacterial partners as a tool for increasing soybean yields in Iran; however, its general analytical framework could be applied to other parts of the world.     

水分胁迫及VA菌根接种对绿豆生长的影响

本文采用土培试验研究了水分胁迫下接种VA菌根真菌Glomusmosseae,G .sp .和G .caledonium对绿豆生长及代谢活动的影响。结果表明 ,水分胁迫严重抑制了植株的生长 ,但对VA菌根真菌的侵染能力影响不大。接种VA菌根真菌不仅有利于植株对土壤中磷和氮的吸收 ,而且明显改善了植株的水分状况 ,降低了植株叶片的脯氨酸含量 ,提高了接种株叶片的光合效率 ,显著增加了植株干物质量 ,增强了绿豆的抗旱性或耐旱性。 3种真菌中 ,以Glomusmosseae的接种效果最好。