接种丛枝菌根真菌和施用磷石膏对烤烟生长及砷累积的影响

为了探讨丛枝菌根真菌（Arbuscular mycorrhizalfungi,AMF）对烤烟生长及磷石膏农用安全的影响,通过盆栽模拟试验研究了磷石膏（Phosphogypsum,PG）不同添加量[0、40mg·g^-1（PG0、PG40）1和接种两种AMF[Glomus massecle（GM）、G．aggregatum（GA）】对烤烟（KRK26）苗期生长及其磷（P）、硫（S）、砷（As）吸收的影响。试验结果表明：无论是否接种AMF,磷石膏的添加均显著增加了KRK26地上部生物量及其植株s含量、吸收量及吸收效率;除不接种处理（NM）的烤烟根系外,PG40处理显著增加了KRK26植株P含量、吸收量及吸收效率,并显著降低了NM处理的地上部As含量及吸收量,进而增加了磷砷吸收比。相同PG添加水平下,与不接种相比,接种GM和GA均显著增加了KRK26植株的生物量。除PGO处理的烤烟根系外,接种GM显著增加了KRK26植株P、S含量与吸收量及吸收效率,以及植株As含量及吸收量,并显著增加了PG40处理的植株磷砷吸收比;接种GA也显著增加了KRK26植株P、S含量及吸收量,并显著降低了PG0处理地上部As含量及吸收量。所有复合处理,以添加磷石膏40mg·g^-1和接种GA处理对KRK26的生长促进效果较好,对磷石膏施用造成的As污染有一定抵御作用。     

砷胁迫条件下接种丛枝菌根真菌对番茄生长和磷吸收的影响

采用盆栽法研究了砷(As)污染条件下(As 0,50,100和200 mg·kg-14个水平)丛枝菌根真菌(AMF)接种对全生育期番茄植株生长及其磷(P)营养的影响。试验中各接种处理均成功侵染,侵染率在11.79%~34.36%之间。砷胁迫显著影响番茄植株的生物量,植株生长过程中各个时期地上部和根系干重均随As添加水平的升高而显著下降。本试验同时发现As 50 mg·kg-1是不接种番茄植株忍受砷毒害的上限,而接种丛枝菌根真菌后,番茄忍受砷毒害的上限上调到100 mg·kg-1;但200 mg·kg-1已达番茄忍受砷毒害的极限。基质中添加砷对番茄植株不同生长时期地上部和根部磷含量有显著影响。除开花期地上部与其不接种处理根部磷含量外,幼苗期和坐果期植株地上部磷含量与根部磷含量均随着砷添加量的增加而呈大致递增趋势。番茄植株生长的各个时期(幼苗期、开花期和坐果期)地上部和根部磷吸收量随砷添加水平的增加呈明显下降趋势。砷污染条件下,接种丛枝菌根在一定程度上促进了植株生长及其对磷的吸收,缓解了砷对植株生长的胁迫。     

丛枝菌根真菌在植物修复砷污染土壤中的作用

丛枝菌根真菌能增强植物对矿质元素的吸收、提高植物的抗逆性、增强抗病性、改善植物根际微环境,减轻重金属对植物的毒害,影响植物对重金属的吸收和转运,在重金属污染土壤的植物修复中显示出极大的应用潜力。近年来,As污染已成为全球非常突出且急需解决的环境问题之一,对As污染土壤的生物修复也因而成为研究热点。本文主要从丛枝菌根真菌改变土壤pH和酶活性、增强植物对As的耐性和影响植物对As的吸收方面综述了丛枝菌根在As污染土壤修复中应用的研究进展,揭示出菌根应用在As污染土壤中的作用潜力和研究方向。     

菌根技术对磷石膏农用的强化效应

磷石膏资源农业利用的可行性已成为磷复肥生产实现可持续发展的关键,而菌根技术的引入可能是磷石膏在低硫缺磷土壤上农用的有效新途径。该文以小葱（Allium schoenoprasum L.）为供试植物进行模拟试验,研究添加不同量（0、20、40 g/kg）磷石膏（phosphogypsum,PG）和接种不同丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）（Glomus mosseae、Glomus aggregatum、Diversispora spurcum）对其生长及磷、硫、砷吸收的影响。结果表明：小葱植株生物量、磷、硫、砷含量及磷砷吸收比均随磷石膏添加水平的提高而有增加趋势。与未接种相比较,在添加了磷石膏的基础上接种上述AMF均能不同程度改善小葱生长并促进其磷素养分的吸收,而添加40 g/kg 磷石膏（PG40）处理接种Glomus mosseae（GM）和Diversispora spurcum（DS）的宿主植株砷含量显著较低,其中以PG40-GM组合处理的小葱生长量、磷、硫吸收量及磷砷吸收比最大,在缺磷低硫土壤上促生效果最好。PG20添加水平时接种上述任意AMF后的小葱砷含量明显降低（且在食品砷限量标准范围内）;而PG40添加水平时只有接种DS的小葱砷含量基本在限量标准之内,且抗砷效果较好。     

接种丛枝菌根真菌对甘薯生长的影响研究

温室盆栽试验研究 3种丛枝菌根真菌 (AM )对甘薯生长的影响结果表明 ,灭菌土壤条件下接种 3种AM真菌 (GlomusmosseaeBEG16 7GlomusintraradicesBEG14 1和Glomussp .WUM2 6 )均不同程度促进甘薯对P的吸收和植株生长 ,其中BEG16 7和BEG14 1对甘薯效应显著高于WUM2 6 ;各接种处理菌丝长度差异及琥珀酸脱氢酶(SDH)活性与其对甘薯的生长效应基本一致 ;接种BEG16 7和BEG14 1的生长效应无显著差异 ,但接种BEG16 7菌丝长度显著大于BEG14 1,其原因可能是BEG16 7菌丝活性低于BEG14 1所致。未灭菌土壤条件下接种 3种AM真菌对甘薯的生长效应不显著 ,而土著AM真菌繁殖体数量较多可能是影响其接种效果的主要原因。     

供硫和丛枝菌根真菌对洋葱生长和品质的影响

以珍珠岩为植物的生长基质盆栽试验,分别供给0.1、1.75和4 mmol/L三个不同硫水平的Long Ashton营养液,研究接种丛枝菌根真菌Glomus versiform对洋葱（Allium cepa L.）生长和品质的影响。结果表明,接种丛枝菌根真菌显著的改善了宿主植物的磷营养水平,促进了洋葱的生长;而硫处理对洋葱生长的影响差异不显著,但随着供硫水平的提高植株地上部全硫含量和有机硫含量显著增加。接种菌根真菌对洋葱硫营养的影响受外界供硫水平的影响,在供硫0.1 mmol/L时降低了洋葱植株的硫含量;而在供硫1.75和4 mmol/L时显著改善了洋葱的硫营养状况,宿主植物的酶解丙酮酸（enzyme produced pyruvic acid, EPY）的含量也显著增加。说明丛枝菌根真菌能够帮助宿主植物吸收外界环境中硫营养成分,改善洋葱的硫营养状况及品质。     

丛枝菌根真菌对玉米生长生态效应的影响

１９９６～１９９８年试验研究了大田不施肥条件下３种泡囊丛枝菌根真菌Ａｒｂｕｓｃｕｌａｒ ｍｙｃｏｒ－ｒｈｉｚａｌ ｆｕｎｇｉ （ＡＭＦ）,即Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ（Ｇ．ｍ）、Ｇｌｏｍｕｓ ｖｅｒｓｉｆｏｍｅ（Ｇ．ｖ）、Ｓｃｌｅｒｏｃｙｓｉｓ ｓｉｎｏｕｓａ（Ｓ．ｓ）对玉米生长的生态效应。结构表明,ＡＭＦ处理的玉米根系活力为对照的２．３２～３．０５倍,玉米Ｎ素吸收比对照增加２４．１４％～５６．     

砷污染土壤中接种丛枝菌根真菌和蚯蚓对土壤线虫群落和植物砷吸收的影响

The influences of arbuscular mycorrhizal fungi (MF, Acaulospora spp. and Glomus spp.), rice straw and earthworms (RE, Eisenia foetida) on nematode communities and arsenic (As) uptake by maize (Zea mays L.) in As-contaminated soils were examined in a field experiment conducted in Wujiang, Jiangsu Province, China. The experiment was designed as a 2 × 2 factorial with the factors of MF (inoculated or uninoculated) and RE (added or not added). The results demonstrated that MF inoculation led to significantly higher root colonization of MF and root dry weight. Plants inoculated with both MF and RE had the highest As concentrations in root. The number of total nematodes increased with MF inoculation when RE was absent, and decreased with RE addition when MF was inoculated. The improved abundance of nematodes with the MF treatment implied that the tested MF acted as food sources for fungivores. The abundances of omnivores-predators and plant parasites were reduced by earthworm activity. Twenty-seven genera of nematodes were identified, with Filenchus dominant in all treatments. Trophic diversity (TD), Shannon-Weaver diversity (H′), Simpson dominance index (λ), and species richness (SR) indicated higher species diversity, more proportionate species composition, evenly distributed species, and more food sources in the MF, RE, and their interaction treatments. Maturity index (MI) showed a moderately disturbed environment due to As pollution. Besides enhancing plant uptake of contaminants, MF and RE amendments could also improve soil health by restoring the structure of soil communities, as reflected by more stable nematode community structure.     

接种丛枝菌根真菌对脱毒马铃薯微型薯生长及产量的影响

在大田条件下采用混合菌种(Glomus mosseas+Glomus intraradices)作为接种剂,研究了接种丛枝菌根真菌对脱毒马铃薯微型薯菌根侵染、磷吸收和产量的影响。结果表明,接种菌根真菌,马铃薯菌根侵染率增加73.3%,植株吸磷量增加15.4%,块茎产量增加8.0%。上述结果证明,在大田条件下,接种菌根真菌能侵染马铃薯根部,促进植株对磷的吸收,从而增加产量。     

不同施肥量条件下AM真菌对烟苗生长及营养状况的影响

试验设置不同施肥量,于播种期分别接种根内球囊霉菌(Glomus intraradices Smith和Schenck,BEG193)和幼套球囊霉菌(Glomuse etunicatum Becker和Gerdemann,BEG168),探索了利用烤烟漂浮育苗技术生产菌根化烟苗和培育壮苗的可能性。结果表明:随着养分供应量的减少,AM真菌的侵染率提高,BEG193的侵染率高于BEG168。减施肥料总体上抑制烟苗生长,使烟苗生物量降低;但接种AM真菌显著促进烟苗生长,烟苗平均生物量比不接种的处理增加了74.38%(BEG168)和48.32%(BEG193)。接种BEG168使烟苗氮、磷、钾含量显著增加;接种BEG193主要是提高了烟苗含磷量。在施肥量减少75%辅以少量追肥的情况下,接种BEG168之后,烟苗生长状况和磷、钾含量超过或与常规施肥的非菌根苗相似。因此,在集约化烤烟漂浮育苗过程中,可采用接种AM真菌BEG168的方式培育壮苗,同时降低施肥量,减轻废弃营养液产生的环境污染。此外,接种AM真菌显著提高基质中的酸性磷酸酶活性,菌根苗基质中的磷酸酶活性随施肥量的降低而逐渐升高。因此,接种AM真菌有益于基质中有机磷的吸收利用,这可能是菌根烟苗含磷量提高的重要原因之一。     

转Bt基因作物对丛枝菌根真菌的影响研究进展

在过去的十年里，世界范围内转基因作物尤其是抗虫性转Bt基因作物的品种和种植面积迅速增加。同时，转Bt基因作物的环境安全性评价问题成为人们关注和研究的热点。丛枝菌根真菌（AMF）是生态系统中普遍存在的土壤微生物，能与绝大多数植物种类形成共生关系，在农业生态系统中起重要作用。转Bt基因作物环境释放后，其与AMF问的共生关系是否受所转入Bt基因的影响，以及影响机制需要及时研究。为此，综述了转Bt基因作物与AMF共生特征方面的研究进展，并根据Bt毒素发生的空间和时间规律提出了危害机制以及转Bt基因植物的规模化种植将降低农田系统中的AMF的生物多样性的观点。     

AM真菌对烟苗生长及某些生理指标的影响

在低浓度营养液条件下,利用漂浮育苗技术培育烟苗,于播种期、小十字期、生根期分别接种不同的AM真菌,研究了它们对烟苗生长、营养和某些生理指标的影响。结果表明,越早接种AM真菌,其侵染率越高;播种期接种,侵染率达到39.2%～59.6%。AM真菌的菌根效应因菌种(株)不同而异,接种球囊霉真菌（BEG-141）后,显著增加烟苗干重、磷含量、氮磷钾吸收量、叶绿素含量,以及根系硝酸还原酶、超氧化物歧化酶和几丁质酶活性。表明在漂浮育苗技术中,播种期接种适宜的AM真菌是培育壮苗的有效措施。     

长期保护性耕作对丛枝菌根真菌多样性的影响

为了明确我国北方干旱地区长期保护性耕作以及深松对丛枝菌根真菌(AMF)多样性的影响,笔者于2014年在山西省临汾市连续22年实施保护性耕作的长期定位试验基地,针对免耕覆盖(NTS)、深松免耕覆盖(SNTS)及传统耕作(TT)3种处理方式,进行了不同耕作条件下土壤AMF物种丰度、孢子密度、Shannon多样性指数以及AMF侵染率等因素的比较研究。结果显示,长期保护性耕作(NTS和SNTS)共分离鉴定出AMF 7属9种,其中根孢囊霉属(Rhizophagus)和斗管囊霉属(Funneliformis)各2种,球囊霉属(Glomus)、近明球囊霉属(Claroideoglomus)、无梗囊霉属(Acaulospora)、硬囊霉属(Sclerocystis)和隔球囊霉属(Septoglomus)各1种;而传统耕作(TT)共分离鉴定出AMF 6属8种,没有检测到无梗囊霉属。NTS、SNTS和TT处理在不同土层的AMF优势种基本一致,0~40 cm土层为摩西斗管囊霉(Fu.mosseae)和变形球囊霉(G.versiforme),40~80 cm土层为摩西斗管囊霉、变形球囊霉和聚丛根孢囊霉(Rh.aggregatum),80~120 cm土层为聚丛根孢囊霉,120 cm土层以下只有NTS和SNTS处理中存在聚丛根孢囊霉,说明保护性耕作措施促进了AMF向土壤深层发展。NTS和SNTS处理在同一土层的AMF物种丰度、孢子密度和Shannon多样性指数均高于TT处理,SNTS处理高于NTS处理。同一耕作措施不同土层的AMF物种丰度、孢子密度和Shannon多样性指数均随土层加深而逐渐降低;NTS和SNTS处理在小麦各生育期的丛枝侵染率和孢子密度均高于TT处理;各处理在小麦拔节期的AMF侵染率最高,分别为14.9%、16.1%和10.6%,而在收获期的土壤孢子密度最高,分别为111.7个·(100g)~(-1)、125.0个·(100g)~(-1)和90.3个·(100g)~(-1)。研究认为,长期免耕覆盖、尤其深松免耕覆盖,提高了AMF多样性。该研究结果可为中国北方旱作农田生态系统中AMF自然潜力的充分发挥,以及保护性耕作技术的合理应用提供科学依据。     

Chronic nitrogen deposition and the composition of active arbuscular mycorrhizal fungi

A growing body of evidence indicates that atmospheric nitrogen (N) deposition can alter the composition and function of arbuscular mycorrhizal fungi (AMF) associated with plant roots. We studied the community of AMF actively transcribing ribosomal genes in the forest floor of northern hardwood forests dominated by sugar maple (Acer saccharum Marsh.) that have been exposed to experimental N deposition since 1994 (30 kg NO₃⁻-N ha⁻¹ year⁻¹). Our objective was to evaluate whether previously observed declines in AM root infection and mycelial production resulted in a compositional shift in the AM fungi actively providing resources to plant symbionts under chronic N deposition. To accomplish this task, we cloned and sequenced the LSU of reverse-transcribed AM fungal rRNA extracted from the forest floor under ambient and experimental N deposition treatments. We found that experimental N deposition did not alter the active community of AMF or AMF diversity, but we did observe a significant decrease in rare taxa under chronic N deposition. Our results indicate that chronic N deposition, at levels expected by the end of this century, can exert a moderate influence on the composition and abundance of AMF associated with plant roots in a wide-spread forest ecosystem in the northeastern North America.     

Effect of arbuscular mycorrhizal fungi on rhizosphere organic acid content and microbial activity of trifoliate orange under different low P conditions

ABSTRACT

Arbuscular mycorrhizal (AM) fungi can improve plant phosphorus (P) uptake; however, information about how AM fungi affect rhizosphere organic acid and microbial activity to alleviate citrus low P stress is limited. Here, a pot experiment was conducted to evaluate the effect of AM fungi (Rhizophagus intraradices, Ri) inoculation on rhizosphere organic acid content, microbial biomass (MB) and enzyme activity of trifoliate orange (Poncirus trifoliata L. Raf.) seedlings grown under three low P conditions. The results showed that mycorrhizal seedlings all recorded higher P concentrations, plant biomass and better root morphology with more lateral and fine roots, but lower root mass ratios, irrespective of P conditions. Mycorrhizal P absorption contribution did not differ significantly among three P conditions. Mycorrhizal seedling rhizosphere soil exhibited lower organic acid content, soil organic P content and ratio of MB-carbon (C)/MB-P, but higher MB and enzyme activity. Additionally, the main organic acids showed a negative relationship with mycorrhizal colonization rate and hyphal length; however, phosphatase and phytase activity had a significantly positive relationship with MB. Therefore, the results suggest that AM fungi inoculation may help citrus to efficiently utilize organic P source by improving microbial activity under low available P conditions.