Soil tillage and herbicide applications in pea: arbuscular mycorrhizal fungi,plant growth and nutrient concentration respond differently

ABSTRACT

We conducted a field- and pot experiment with peas to investigate the impact of soil tillage and herbicide applications on arbuscular mycorrhizal fungi (AMF), plant growth, phosphorus concentrations, C:N ratio in plants and yield. The field study was carried out in a long-term soil tillage experiment where four tillage treatments have been compared. Field soil from the experimental plots were used for the pot experiment. AMF were not affected by herbicide (MCPB) application, neither in the field nor in the pot experiments. However, AMF root colonization was enhanced by reduced tillage, minimum tillage and no-tillage practices, compared to conventional tillage. In the pot experiment, plant growth and nodulation of pea roots was negatively affected by the high herbicide dosage. In the field experiment neither tillage nor herbicide treatment exert specific effects on root growth parameters, phosphorus concentrations, C:N ratio and plant dry matter. This work demonstrates that an appropriate herbicide usage coupled with conservation soil tillage techniques can favour AMF root colonization and benefit plant growth.

Abbreviations: AMF: arbuscular mycorrhizal fungi; CT: conventional tillage; RT: reduced tillage; MT: minimum tillage; NT: no tillage; P: Phosphorus; C:N ratio: carbon:nitrogen ratio     

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 mycorrhizal fungi (AMF),即 Glomus mosseae(G.m)、Glomus versifome(G.v)、Sclerocystis sinousa(S.s)对玉米生长的生态效应.结果表明,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%～56.65%,玉米P素吸收比对照增加41.14%～78.29%,促进玉米生长发育显著;在灭菌条件下G.m、G.v、S.s处理分别比对照增产17.63%、22.91%和10.80%;而不灭菌条件下3个处理分别比对照增产10.35%、20.56%和4.53%,同时显著提高玉米的水分供应状况.     

Reaction of Mycorrhizal and Nonmycorrhizal Leucaena leucocephala to Charcoal Amendment of Mansand and Soil

A series of experiments were conducted to evaluate the influence of charcoal on the development of arbuscular mycorrhiza (AM) on Leucaena leucocephala roots and the contribution of the symbiosis to the phosphorus (P) nutrition and growth of the legume. Arbuscular mycorrhizal fungal colonization of plants raised in Mansand (crushed basalt) in the first experiment was reduced if the medium was amended with fine charcoal and not with coarse charcoal. Charcoal amendment had no effect on AM fungal colonization, AM symbiotic effectiveness measured as pinnule (subleaflet) P content, or on growth of L. leucocephala in soil in the first experiment and in Mansand and in soil in subsequent experiments. However, AM fungal colonization of L. leucocephala roots, P content of pinnules, and growth of the legume were significantly enhanced (P < 0.05) by AM fungal inoculation in all experiments regardless of the growth medium used or charcoal amendment.     

丛枝菌根提高植物耐盐性的研究进展

近年来,土地盐渍化越来越多的引起人们的关注,已成为最常见的农业问题之一,其对人类造成的危害主要是使农作物减产甚至绝收,并间接造成生态环境恶化。研究表明丛枝菌根真菌(Arbuscular Mycorrhiza Fungi,AMF)在盐胁迫下能与很多种植物共生,能够提高植物的耐盐性,促进植物在盐胁迫中生长。因此,探索AMF缓解盐胁迫对植物的危害是近年来生态学和农业生产中的热点问题。综述了AMF在植物干物质的积累、营养吸收、渗透调节、抗氧化酶系统、叶绿素浓度、水分状况、植物激素信号以及一些耐盐相关基因方面国内外最新的研究成果,并对利用AMF提高植物耐盐性相关研究提出了展望,以期为盐碱地的改良及农业生产提供参考依据。     

柑橘砧木和砧穗组合对丛枝菌根发育的影响

倍体体细胞杂种砧木)对丛枝菌根发育的影响。结果表明,柑橘丛枝菌根侵染幅度为 4.88 % ~ 40.52 %,土壤内孢子密度不等,大致在 347 ~ 750 个孢子/kg(干土)内。田间菌根侵染率和孢子密度在不同土层深度的分布以深度 10 ~20 cm 为最高。遗传关系相近的国庆 1 号/枳和国庆 4 号/枳组合间以及红肉脐橙/罗伯逊脐橙 36 号/枳和纽荷尔脐橙/罗伯逊脐橙 36 号/枳间的丛枝菌根发育没有显著差异,与红肉脐橙和纽荷尔脐橙遗传关系远的脐血橙组合,较红肉脐橙和纽荷尔脐橙组合的孢子密度间有极显著差异。红桔 枳的菌根侵染率和土壤孢子密度均最高,且显著高于其他 4 种砧木。盆栽砧木孢子密度与菌根侵染率呈显著正相关性。10 种试材的根围土壤孢子密度与菌根侵染率间呈极显著正相关性。     

玉米与马铃薯间作对作物根际土壤丛枝菌根真菌群落的影响

   研究间作对作物根际土壤理化性质、球囊霉素相关土壤蛋白含量和AMF群落的影响,为我国南方红壤坡耕地种植模式的选择提供理论依据。   以红壤坡耕地为研究对象,设置玉米单作、马铃薯单作、玉米与马铃薯间作3个处理,分析各作物在不同种植模式下其根际土壤理化性质、球囊霉素相关土壤蛋白含量、AMF群落的组成和多样性的变化,以及各指标之间的相互关系。   玉米、马铃薯间作与单作相比均显著增加了两种作物根际土壤总球囊霉素和易提取球囊霉素含量,增加幅度为10.5% ~ 30.1%。玉米间作与玉米单作相比根际土壤有机质含量显著降低了10.6%,马铃薯间作与马铃薯单作相比根际土壤有机质和速效磷含量分别显著增加了13.5%和46.5%。玉米间作相比于玉米单作其根际土壤AMF群落特有的操作分类单元数量有增加趋势,而马铃薯间作相比马铃薯单作有降低趋势。非度量多维尺度法分析结果表明,种植模式较明显的改变了玉米根际土壤中AMF的群落组成,但没有明显改变马铃薯根际土壤中AMF的群落组成。玉米间作与玉米单作相比根际土壤AMF群落的Chao1指数显著增加了9.3%,香农指数有增加趋势,其值为1.3%,辛普森指数有降低趋势,其值为7.6%。马铃薯间作与马铃薯单作相比根际土壤AMF群落的辛普森指数有增加趋势,其值为53.3%,Chao1指数显著降低了10.8%,香农指数有降低趋势,其值为10.6%。在玉米、马铃薯的各处理中,根际土壤AMF群落优势属为巨孢囊霉属、无梗囊霉属和根孢霉属。冗余分析得出,pH是影响作物根际土壤AMF群落丰度、α多样性指数和球囊霉素相关土壤蛋白含量的主要因素。   玉米与马铃薯间作可显著增加作物根际土壤的球囊霉素相关土壤蛋白含量,提高玉米根际土壤AMF群落组成的多样性,这一研究结果可为云南省红壤坡耕地种植模式的选择提供理论依据。     

Improved zinc tolerance in Eucalyptus globulus inoculated with Glomus deserticola and Trametes versicolor or Coriolopsis rigida

The potential of interactions between saprophytic and arbuscular mycorrhizal (AM) fungi to improve Eucalyptus globulus grown in soil contaminated with Zn were investigated. The presence of 100 mg kg ⁻¹ Zn decreased the shoot and root dry weight of E. globulus colonized with Glomus deserticola less than in plants not colonized with AM. Zn also decreased the extent of root length colonization by AM and the AM fungus metabolic activity, measured as succinate dehydrogenase (SDH) activity of the fungal mycelium inside the E. globulus root. The saprophytic fungi Trametes versicolor and Coriolopsis rigida increased the shoot dry weight and the tolerance of E. globulus to Zn when these plants were AM-colonized. Both saprophytic fungi increased the percentage of AM root length colonization and elevated G. deserticola SDH activity in the presence of all Zn concentrations applied to the soil. In the presence of 500 and 1000 mg kg⁻¹ Zn, there were higher metal concentrations in roots and shoots of AM than in non-AM plants; furthermore, both saprophytic fungi increased Zn uptake by E. globulus colonized by G. deserticola. The higher root to shoot metal ratio observed in mycorrhizal E. globulus plants indicates that G. deserticola enhanced Zn uptake and accumulation in the root system, playing a filtering/sequestering role in the presence of Zn. However, saprophytic fungi did not increase the root to shoot Zn ratio in mycorrhizal E. globulus plants. The effect of the saprophytic fungi on the tolerance and the accumulation of Zn in E. globulus was mediated by its effect on the colonization and metabolic activity of the AM fungi.     

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。     

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。     

丛枝菌根生理生态功能及其在生态恢复中的作用

近年来生态系统退化、环境污染等问题日趋严峻,生态恢复成为国内外关注的热点之一。丛枝菌根是陆地生态系统中分布最广泛、最重要的互惠共生体之一,对提高植物抗逆性、植被恢复、保持生态系统稳定与可持续生产力的作用显著。本文重点综述丛枝菌根的生理生态功能,及其在矿区土壤、旱区和盐碱土壤、退化草原等生态重建中的应用潜力,并对未来研究方向进行了探讨,旨在为生态恢复提供一条新途径。     

Effects of Inoculation with Glomus mosseae in Conventionally Tilled and Nontilled Soils with Different Levels of Nitrogen Fertilization on Wheat Growth,Arbuscular Mycorrhizal Colonization,and Nitrogen Nutrition

Evaluation of the performance of inoculants in undisturbed and unsterilized soils, where diverse communities of microorganisms are present, is a necessary step before using arbuscular mycorrhizal fungi (AMF) in agricultural technology. The effects of inoculation with Glomus mosseae on arbuscular mycorrhizal colonization, growth, and nitrogen (N) uptake of wheat plants in unsterilized tilled and untilled soils from the Argentinean Pampas with different levels of N fertilization were assessed. The fertilization and inoculation effects depended on the tillage treatments. In no-tillage, the colonization was greater than in conventional tillage, but it was reduced by the N fertilization. In conventional tillage, the inoculation with G. mosseae increased colonization. Both conventional tillage and N fertilization promoted wheat root growth. Inoculation did not affect root growth but enhanced N concentration in roots when fertilizer was not applied.     

Effect of tillage and crop on arbuscular mycorrhiza colonization of winter wheat and triticale under Mediterranean conditions

Large‐scale inoculation with arbuscular mycorrhizal fungi (AMF) is generally impractical in most regions and we have little understanding of the factors that determine inoculation success. Nevertheless, the ability to take full advantage of indigenous AMF for sustainable production needs to be developed within cropping systems. We used part of a long‐term field experiment to understand the influence of tillage and the preceding crop on AMF colonization over the growing season. Arbuscular mycorrhiza colonization rate was more affected by treatment (tillage or the combination of crop and preceding crop) than by the total number of AMF spores in the soil. Conventional tillage (CT) had a statistically significant negative effect (P ≤ 0.05) on spore numbers isolated from the soil, but only in the first year of study. However, the AMF colonization rate was significantly reduced by CT, and the roots of wheat, Triticum aestivum, L, cv. Coa after sunflower, Helianthus annuus L., were less well colonized than were those of triticale, X Triticosecale Wittmack, cv. Alter after wheat, but the affect of tillage was more pronounced than was the effect of crop combination. Under no‐till there was a significant increase in AMF colonization rate throughout the sampling period in both wheat and triticale, indicating that the extraradical mycelium previously produced acted as a source of inoculum. In general, triticale showed greater AMF colonization than wheat, despite the preceding crop being less mycotrophic. Under these experimental conditions, typical of Mediterranean agricultural systems, AMF colonization responded more strongly to tillage practices than to the combination of crop and preceding crop.     

Mycorrhizas Mitigate Soil Replant Disease of Peach Through Regulating Root Exudates,Soil Microbial Population,and Soil Aggregate Stability

Soil replant disease is the main bottleneck interfering with tree growth of peach in soils with poor traits. A potted study was conducted to evaluate the effects of inoculation with an arbuscular mycorrhizal fungus (AMF), Acauloapora scrobiculata, on plant growth, mineral nutrients, soil enzyme activities, soil microbial populations, and root exudate compositions of peach (Prunus persica L. Batsch) seedlings grown in replant soil and non-replant soil. After 15 weeks in AMF inoculation, replant soil heavily inhibited root mycorrhizal colonization. In replant soil, AMF inoculation significantly increased shoot biomass and root phosphorus, potassium, calcium, copper, zinc, iron, and boron concentrations. Mycorrhizal peach seedlings showed a higher number of soil bacteria and total microbes but a lower number of soil fungi under replant conditions, as well higher soil urease and acid phosphatase activity and lower soil sucrase and catalase activity. Greater soil aggregate stability was observed in mycorrhiza-inoculated replant soil than in non-mycorrhizal soil due to the increase of water-stable aggregates in 2–4 mm and 1–2 mm size. In addition, a total of 92 substances were identified in root exudates, and the mycorrhizosphere had considerably more root exudate compositions. AMF inoculation had a significantly inhibitive effect on the relative abundance of allelochemical substances, including benzoic acid, benzaldehyde, diisooctyl phthalate, phenols, and sterols, while there was an increase in diphenyl-ethanedione and à-(benzoyloxy)-benzeneacetonitrile in replanted peach. It was concluded that AMF inoculation could partly mitigate soil replant disease of peach through modulating soil microbe balance, improving soil aggregate stability, and changing root exudate compositions.     

农田生态系统杂草的养分和水分效应研究

通过田间试验研究了冬小麦田杂草的土壤养分和水分效应．发现田间保留一定量的杂草能够提高表层土壤水分含量,尤以0～20cm层次表现明显,显示出很好的土壤水分保持效应。同时在保留杂草的处理中,0～60cm土壤碱解氮储量消耗最少．速效P储量在增加．而速效K储量增加得最多。并且在冬小麦返青期不论土壤养分情况怎么样．在收获后都以保留杂草的处理土壤速效养分(碱解氮、速效磷和速效钾)储量最高．表现出较高的土壤养分供给能力。     

冬季积雪变化背景下AM真菌对荒漠土壤胞外酶活性的影响

土壤胞外酶作为土壤生物化学反应的催化剂,直接驱动了土壤物质循环和能量流动过程,土壤胞外酶活性对冬季积雪变化响应敏感,对于缺水且养分贫瘠的荒漠生态系统养分循环过程影响显著。为研究暖湿趋势下古尔班通古特沙漠冬季积雪变化和丛枝菌根（Arbuscular mycorrhiza,AM）真菌对土壤酶活性的影响,设置冬季积雪变化和原位抑制AM真菌活性的双因素长期定位试验,采用裂区随机区组试验设计,主区为对照（增水40 mm,W）和AM抑制处理（增水40 mm同时添加苯菌灵,BW）,副区为积雪增加100%(+S)、自然降雪（CK）和积雪减少100%(-S)。分土层采集土壤样品,测定不同处理下土壤理化性质及土壤碳、氮和磷循环相关酶活性,分析冬季积雪变化背景下AM真菌对荒漠土壤酶活性和微生物代谢限制的影响。结果表明：（1）AM真菌提高了植物地上部净初级生产力;降低土壤中速效磷和铵态氮含量,增加有机碳含量;在积雪增加和自然降雪基础上,AM真菌降低了土壤中与碳、氮和磷循环相关的酶活性;积雪减少基础上,AM真菌增加了碳和氮循环相关酶活性。（2）通过矢量分析得出,荒漠土壤微生物活性受土壤碳和磷的限制,在积雪增加和自然降雪基础上,AM真菌降低了土壤中微生物碳限制,在积雪减少基础上,AM真菌对土壤微生物碳和磷限制影响无一致性规律。综上所述,冬季积雪变化背景下,AM真菌对促进荒漠土壤速效磷和铵态氮吸收,提高土壤碳和氮循环相关酶活性,缓解土壤微生物碳限制等方面均起到重要作用。     

设施蔬菜土壤丛枝菌根真菌多样性及群落构建的季相变化

摘 要：为研究设施生态系统丛枝菌根（Arbuscular mycorrhiza, AM）真菌群落变化的关键驱动过程,采集设施番茄不同生长季（休耕、花期、果期）土壤样品,利用Illumina MiSeq高通量测序技术分析AM真菌物种和谱系多样性及群落结构变化特征,并结合群落谱系分析方法探讨不同生长季随机性过程和确定性过程之间的相对贡献。结果表明,不同生长季AM真菌的物种多样性和谱系多样性均发生显著改变：相比于休耕期,番茄生育期（花期、果期）土壤中AM真菌丰富度、Shannon多样性、Pielou均匀度、谱系多样性（PD）和平均成对谱系距离（MPD）分别显著下降了42.82%~59.18%、43.25%~48.31%、17.46%~25.40%、57.14%~67.86%和50.00%;除球囊霉属相对多度显著增加,近明球囊霉属和类球囊霉属相对多度均显著下降,原囊霉属相对多度先增加后降低。置换多元方差分析（PERMANOVA）和非度量多维度分析（NMDS）结果表明休耕期基于物种组成和谱系组成的AM真菌群落结构显著差别于番茄生育期,但花期和果期之间差异不显著。谱系分析结果显示,休耕期净亲缘关系指数NRI=0,表明AM真菌在谱系结构上是随机的,花期和果期NRI>0,表明谱系聚集,暗示了AM真菌群落构建由随机性过程主导向确定性过程主导的转变,中性群落模型（NCM）结果也支持该推断。Mantel检验结果显示,土壤pH、养分（有机碳、全量氮磷钾和有效磷）、盐分含量以及土壤温湿度作为确定性因素显著影响AM真菌群落的季相变化。综上所述,设施生态系统高集约化生产方式促进了AM真菌群落构建从随机性过程主导向确定性过程主导转变,导致多样性降低和群落结构变化,研究结果对揭示设施蔬菜栽培条件引起的土壤质量退化及其过程中的微生物组演变规律具有重要意义。