土施糖类对丛枝菌根真菌侵染率和产孢的影响

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)不能进行光合作用,需要宿主植物提供碳水化合物供其完成整个生命周期,添加外源物质调控AMF和宿主植物的关系被认为是一种可行的措施。通过盆栽实验种植番茄,探索土施不同糖类对摩西球囊霉Glomus mosseae的侵染率、产孢能力和功能(宿主植物生长和养分)的影响。结果表明,添加葡萄糖和蔗糖可提高接种了摩西球囊霉的番茄的地上部生物量以及磷、钾吸收量,但对地上部氮吸收量影响不显著;添加麦芽糖和淀粉对地上部生物量及氮磷钾养分吸收量的影响均不显著。添加糖类处理,土壤碱解氮均有下降趋势;土壤速效磷、速效钾随着地上部磷和钾吸收量增加有下降趋势。糖类添加对土壤有机质没有影响。添加不同糖类均提高了AMF的侵染率,其中添加蔗糖处理的侵染率较单独施用摩西球囊霉菌处理增加了114%。单独施用摩西球囊霉菌剂处理土壤孢子数为10个/g,添加葡萄糖和淀粉处理的孢子数均为8个/g,添加蔗糖和麦芽糖处理的孢子数均为11个/g,添加糖类均对AMF产孢无显著影响。     

构树幼苗对接种丛枝菌根真菌的生长响应

利用石灰岩适生植物构树进行菌根真菌摩西球囊霉(GM)、地表球囊霉(GV)和透光球囊霉(GD)的单独接种(SI)、混合接种(CI)和不接种(N)处理试验,测定了构树幼苗生长3个月后的形态及生长指标.结果表明:接种VA真菌促进了宿主构树的生长,单株地上部分、地下部分生物量和全株生物量等生长指标均较对照组显著提高,4种处理下构树幼苗生物量较对照提高了2.49～8.19倍,其中CI处理生物量最大,而单株叶片数目与对照组没有显著差异.不同接种处理的构树幼苗生长响应不同.在SI处理中,GD对构树幼苗生长效应最大,而CI处理较SI处理对构树幼苗的促进效应更加明显.CI处理中地径、苗高和总叶面积分别是对照组的1.5、2.2和6.0倍.各处理中根冠比最大的为CI(0.446).说明宿主植物与菌种存在一定的选择性.     

接种丛枝菌根真菌对青冈栎幼苗生长和光合作用的影响

利用菌根真菌摩西球囊霉和根内球囊霉,对喀斯特地区造林树种青冈栎进行接种试验,测定菌根真菌对青冈栎幼苗生长、生物量和光合作用的影响。结果表明:接种丛枝菌根真菌能显著促进青冈栎幼苗株高、地径、叶面积和幼苗生物量的增长,并且能提高幼苗成活率和改善幼苗的光合能力。摩西球囊霉和根内球囊霉处理的青冈栎幼苗生物量分别是未接种处理的2.1和1.9倍;摩西球囊霉和根内球囊霉处理下的水分利用效率分别比对照处理提高了33.6%和8.8%;摩西球囊霉对青冈栎幼苗株高、地径、生物量的促进作用好于根内球囊霉,而根内球囊霉处理的幼苗叶面积、主根长、根冠比大于摩西球囊霉处理。总体而言,接种丛枝菌根真菌特别是摩西球囊霉能促进青冈栎幼苗的生长和生物量增长,在石漠化植被恢复中具有潜在应用价值。     

丛枝菌根真菌对枳根系形态和蔗糖、葡萄糖含量的影响

研究丛枝菌根真菌接种(摩西球囊霉、地表球囊霉和摩西球囊霉+地表球囊霉)对盆栽枳的生长、根系形态以及蔗糖、葡萄糖含量的影响.结果表明: 3个接种处理都显著提高枳的株高、茎粗、叶片数,以及地上部和地下部生物量,诱导1级、2级和3级侧根的发生,同时增加了根系投影面积、表面积、体积和总长度(主要是0～1 cm根长),但降低根系平均直径,其中以地表球囊霉效果最明显.丛枝菌根真菌接种显著提高枳的叶片蔗糖和根系葡萄糖含量,但降低叶片葡萄糖和根系蔗糖含量.由于根系“菌根碳库”的存在,丛枝菌根真菌接种导致根系维持较高的葡萄糖和较低的蔗糖含量,从而有利于宿主根系的生长和发育,建立更优的根系形态.     

喀斯特土壤上香樟幼苗接种不同AM真菌后的耐旱性效应

为探索喀斯特土壤适生植物香樟幼苗在接种不同AM真菌后的耐旱适应性,进行了香樟幼苗接种幼套球囊霉(Glomus etunicatum)和层状球囊霉(Glomus lamellosum)后水分胁迫处理试验。结果表明：（1）接种AM真菌显著提高了香樟幼苗的生物量积累,AM促进植株生物量效应依次为中度>轻度>正常>重度,同一水分胁迫处理下生物量幼套球囊霉>层状球囊霉。（2）中度干旱下香樟幼苗菌根依赖性最大,幼套球囊霉接种植株的菌根依赖性较层状球囊霉大。（3）接种AM真菌显著提高了植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量,并降低了丙二醛含量;在正常供水下植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量层状球囊霉接种>幼套球囊霉接种>对照,干旱胁迫下表现为幼套球囊霉接种>层状球囊霉接种>对照;干旱胁迫下的幼套球囊霉接种植株丙二醛含量低于层状球囊霉接种植株。（4）总体上,可溶性糖与脯氨酸相关性极显著,可溶性蛋白质与丙二醛之间呈显著负相关性。幼套球囊霉接种香樟幼苗的耐旱性高于和层状球囊霉接种香樟幼苗。     

接种丛植菌根真菌对湿生植物氮磷吸收能力的影响

丛枝菌根(Arbuscular mycorrhizal,AM)真菌是一类能够与大多数陆生植物共生,并改善植物生长和氮磷吸收的微生物.湿生植物在湿地污染净化过程中起着决定性的作用,但利用AM真菌改良湿生植物氮磷吸收能力的研究鲜有报道.本研究选取了3种湿生植物千屈菜、旱伞草和黄花鸢尾,在盆栽培养的基础上,分别接种根内球囊霉(RE)、摩西球囊霉(GM)、幼套球囊霉(CE)三种AM真菌,并和空白对照比较接种AM真菌对不同植物地上、地下及整株的生物量和氮磷吸收的影响.结果表明,接种AM真菌对植物生长和氮磷吸收的影响呈现出植物间和植物内的差异,促进与抑制效应表现不一.综合AM真菌对植物生物量和氮磷吸收的促进效应,最佳AM真菌-植物的组合为:千屈菜-RE,旱伞草-RE,黄花鸢尾接种-GM.三种植物接种最佳的AM真菌后植物生物量、TN量和TP量分别提高了17.7%~29.8%、15.7%~39.0%和22.3%~62.6%.本研究为今后强化湿生植物的氮磷吸收能力提供了一种新的可选择的途径.     

感染羽茅的香柱菌属内生真菌对丛枝菌根真菌孢子萌发的影响

内生真菌与丛枝菌根(AM)真菌是构成草原生态系统的重要组成部分.内生真菌会抑制其宿主植物的AM真菌侵染率.本研究以感染2种香柱菌属内生真菌[Epichloё gansuensis(Eg)和E. sibirica(Es)]的天然禾草羽茅为供试材料,进行体外纯培养的内生真菌培养滤液、感染内生真菌的羽茅叶片(包括鲜叶和枯叶)浸提液,以及根系分泌物对摩西球囊霉(Gm)和幼套球囊霉(Ge)2种AM真菌孢子萌发影响试验.结果表明: 香柱菌属内生真菌的培养滤液会显著抑制2种AM真菌孢子的萌发,而感染香柱菌属内生真菌的羽茅根系分泌物只对Ge孢子萌发有显著抑制作用,且上述抑制作用与内生真菌种类无关;鲜叶浸提液对Gm和Ge的孢子萌发率均无显著影响,而枯叶浸提液对Ge的孢子萌发有显著抑制作用.在自然生态系统中,香柱菌属内生真菌通常存在于宿主植物体内,可能通过影响宿主植物的根系分泌物来影响AM真菌孢子的萌发.     

丛枝菌根真菌对黄花蒿生长及药效成分的影响

通过盆栽接种试验,研究丛枝菌根(AM)真菌对药用植物黄花蒿的生长、营养吸收和药效成分的影响.结果表明:接种摩西球囊霉和地表球囊霉增加了黄花蒿对N、P、K的吸收,及叶片叶绿素含量、净光合速率、气孔导度、蒸腾速率、茎粗和地上生物量,尤其以接种摩西球囊霉的促进作用更强;接种摩西球囊霉后植株茎、小枝和叶中的青蒿素含量分别提高了32.8%、15.2%和19.6%,接种地表球囊霉后分别提高了26.5%、10.1%和14.9%;接种摩西球囊霉和地表球囊霉的黄花蒿地上部的挥发油收油率比未接种的分别提高45.0%和25.0%,而且挥发油成分发生了改变.     

丛枝菌根真菌对番茄信号物质的诱导效应

盆栽番茄Lycopersicon esculentum幼苗分别接种丛枝菌根(AM)真菌摩西球囊霉Glomus mosseae、地表球囊霉G.versiforme、根内球囊霉G.intraradices、幼套球囊霉G.etunicatum及珠状巨孢囊霉Gigaspora margarita 35d后,开始测定番茄植株内源信号物质水杨酸(SA)、茉莉酸(JA)、一氧化氮(NO)和过氧化氢(H2O2)含量变化,抗性相关酶活性,丙二醛(MDA)含量以及生长量等指标。结果表明,接种AM真菌增加了番茄植株鲜重、株高、地上部和地下部干重、叶片和根系NO、JA、H2O2含量和结合态SA含量,其中,以摩西球囊霉G.mosseae诱导作用最大,叶片和根系内NO、JA、H2O2和结合态SA含量分别比对照增加了3.3和1.9倍、6.8和8.0倍、0.9和1.2倍、1.9和2.6倍,而根系中游离态SA含量一直处于较低水平,只有摩西球囊霉G.mosseae处理在诱导高峰时根系游离态SA含量比对照略有增加。接种AM真菌处理的番茄叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)活性显著增加,其中以摩西球囊霉G.mosseae的诱导效应最大,与未接种对照相比分别增加了0.6和0.3倍、7.9和3.1倍、0.4和1.2倍、2.3和1.9倍;幼套球囊霉G.etunicatum的诱导效应最小:与未接种对照相比分别增加了0.26和0.14倍、2.3和1.0倍、0.1和0.28倍、0.55和0.31倍;而MDA含量下降,分别降低了66%和68%、34%和41%、51%和50%、12%和26%、18%和29%。表明AM真菌能诱导植物同时产生多种信号物质,而且这些信号参与了AM真菌-番茄共生体系统抗性的表达。     

盐渍条件下AM真菌对大豆生长和离子含量的影响

盐渍条件下研究了丛枝菌根(AM)真菌对大豆Glycine max植株生长和叶片离子含量的影响。结果表明,接种摩西球囊霉Glomus mosseae处理的叶片K+含量和K/Na比显著高于对照,而Na+含量无显著差异。G.mosseae显著增加了大豆植株生长量,这一效应随盐处理浓度的提高而增大。表明盐渍条件下AM真菌提高大豆抗盐性与其增加K+吸收和运输有关。     

Balancing multiple mutualists: asymmetric interactions among plants, arbuscular mycorrhizal fungi, and fungal endophytes

Most organisms engage in beneficial interactions with other species; however, little is known regarding how individuals balance the competing demands of multiple mutualisms. Here we examine three-way interactions among a widespread grass, Schedonorus phoenix , a protective fungal endophyte aboveground, Neotyphodium coenophialum , and nutritional symbionts (arbuscular mycorrhizal fungi) belowground. In a greenhouse experiment, we manipulated the presence/absence of both fungi and applied a fertilizer treatment to individual plants. Endophyte presence in host plants strongly reduced mycorrhizal colonization of roots. Additionally, for plants with the endophyte, the density of endophyte hyphae was negatively correlated with mycorrhizal colonization, suggesting a novel role for endophyte abundance in the interaction between the symbionts. Endophyte presence increased plant biomass, and there was a positive correlation between endophyte hyphal density and plant biomass. The effects of mutualists were asymmetric: mycorrhizal fungi treatments had no significant impact on the endophyte and negligible effects on plant biomass. Fertilization affected all three species – increasing plant biomass and endophyte density, but diminishing mycorrhizal colonization. Mechanisms driving negative effects of endophytes on mycorrhizae may include inhibition via endophyte alkaloids, altered nutritional requirements of the host plant, and/or temporal and spatial priority effects in the interactions among plants and multiple symbionts.     

丛枝菌根真菌对羊草生物量和氮磷吸收及土壤碳的影响

采用大田试验的方法在内蒙古锡林格勒草原进行牧草接种试验,通过灭菌和未灭菌两种土壤研究接种丛枝菌根真菌Glomus mosseae和Glomus claroidium对内蒙古典型草原优势种羊草生长的影响.结果显示,接种丛枝菌根真菌对羊草的地上部干重未产生显著影响,但向未灭菌土壤中接种能显著增加羊草根系量,同时接种G.mosseae显著增加了地上部的N、P含量及吸收量,有效地改善了植株N、P营养,提高了牧草品质;2种菌对根系的营养吸收影响不同,接种G.mosseae在灭菌土壤和未灭菌土壤中均能显著增加根系的N、P吸收量,而接种G.claroidium仅在土壤未灭菌状态下增加根系N、P吸收量;接种对土壤中的菌丝密度未产生显著影响,但接种后土壤中微生物量碳有增加的趋势,短期内难以观察到接种对土壤有机碳的影响.研究表明,丛枝菌根真菌能够提高牧草对N、P吸收,促进牧草的生长,改善牧草品质,增强牧草根际微生物量碳.     

西藏高原天然长芒草地丛枝菌根真菌接种效应

采用草地均匀打孔方法,就草地土壤未消毒条件下接种丛枝菌根（AM）真菌对长芒草(Stipa bungeana)的侵染效应以及对植物生长、吸磷效率、土壤微生物区系等的影响进行研究.结果表明,1)接种处理、不接种处理的菌根效应存在着明显的差异,多数接种处理根围土壤AM真菌孢子密度、菌根侵染率和侵染强度显著提高,但对丛枝丰度的影响相对较低.2)接种后AM真菌孢子密度对菌根侵染率具有极显著影响(r=0.7679**);随菌根侵染率的增加,植株总干物重和吸磷总量均呈极显著提高,r值分别为0.7556**、0.8018**.3)与植株地上部相比,接种AM真菌对提高根系干物重、根系吸磷量和含磷量的促进作用相对较大.4)多数接种处理根际土壤酸性磷酸酶、碱性磷酸酶活性均呈一定程度的提高,根际土壤细菌数量显著增加,真菌、放线菌的数量变化则不甚明显.5)各接种处理对寄主植物的综合侵染效应在总体上呈Glomus mosseae+G. intraradices+Scutellospora calospora＞G. mosseae+G. aggregatum＞Glomus sp.＞G. mosseae＞G. mosseae+ G. etunicatum+G. intraradices+S. erythropa＞G. geosporum的趋势.     

Effects of simultaneous infections of endophytic fungi and arbuscular mycorrhizal fungi on the growth of their shared host grass Achnatherum sibiricum under varying N and P supply

Grasses can be infected by endophytic fungi and arbuscular mycorrhizal (AM) fungi simultaneously. Here, we investigated the interactions of a native grass, Achnatherum sibiricum, with both endophytic and AM fungi (Glomus mosseae, GM and Glomus etunicatum, GE) at different nitrogen (N) and phosphorus (P) levels. The results showed that endophyte infection significantly suppressed the colonization rates and spore density of GE, but had no effect on those of GM. Endophyte infection increased shoot biomass regardless of the nutrient conditions. The effects of AM fungi on host growth were dependent on mycorrhizal species. There was no significant interaction between endophytic fungi and GE on host growth; however, a significant interaction between endophytic fungi and GE occurred in total phenolic concentrations and P uptake. As for GM, a significant interaction among endophytic fungi, AM fungi and nutrient availability occurred in shoot growth. Under sufficient N and P conditions, endophyte infection alleviated the detrimental effects of GM colonization on host growth.     

Role of Extrinsic Arbuscular Mycorrhizal Fungi in Heavy Metal-Contaminated Wetlands with Various Soil Moisture Levels

This study presents an efficient heavy metal (HM) control method in HM-contaminated wetlands with varied soil moisture levels through the introduction of extrinsic arbuscular mycorrhizal fungi (AMF) into natural wetland soil containing indigenous AMF species. A pot culture experiment was designed to determine the effect of two soil water contents (5–8% and 25–30%), five extrinsic AMF inoculants (Glomus mosseae, G. clarum, G. claroideum, G. etunicatum, and G. intraradices), and HM contamination on root colonization, plant growth, and element uptake of common reed (Phragmites australis (Cav.) Trin. ex Steudel) plantlets in wetland soils. This study showed the prevalence of mycorrhizae in the roots of all P. australis plantlets, regardless of extrinsic AMF inoculations, varied soil moisture or HM levels. It seems that different extrinsic AMF inoculations effectively lowered HM concentrations in the aboveground tissues of P. australis at two soil moisture levels. However, metal species, metal concentrations, and soil moisture should also be very important factors influencing the elemental uptake performance of plants in wetland ecosystems. Besides, the soil moisture level significantly influenced plant growth (including height, and shoot and root dry weight (DW)), and extrinsic AMF inoculations differently affected shoot DW.     

接种AM真菌对短命植物生长发育及矿质养分吸收的影响

 采用分室培养方法研究接种幼套球囊霉(Glomus etunicatum，BEG168)、摩西球囊霉(G. mosseae, BEG167)、混合菌剂(M)对两种沙漠早春短命植物小车前(Plantago minuta)和尖喙牻牛儿苗（Erodium oxyrrhynchum）生长发育及矿质养分吸收的影响。结果表明，接种AMF处理的小车前和尖喙牻牛儿苗根系形成了典型的菌根结构，侵染率为22 %～60%；接种AMF提高了小车前和尖喙牻牛儿苗两种植物的生物量、株高及N、P养分吸收量。小车前单独接种BEG167、BEG168以及混合接种都显著提高了单株种子数量，其增幅分别 为67%、50%和78%。上述结果说明，在极端贫瘠和干旱的古尔班通古特沙漠中，丛枝菌根真菌对于早春短命植物小车前和尖喙牻牛儿苗的生态适应性的贡献表现为促进营养生长、提高后代（种子）繁殖数量。     

Nitrogen addition overrides the effects of Stellera chamaejasme litter on the growth of Leymus chinensis and its associated mycorrhizal fungi

氮添加掩盖了狼毒凋落物对羊草生长及其菌根真菌的影响 退化草地上迅速蔓延、生长的有毒植物能产生大量的凋落物,而氮输入能促进有毒植物的生长, 并改变其根际微生物特别是丛枝菌根真菌(AMF)的特征。然而,有毒植物的凋落物如何影响可食牧草的生长及其根际AMF,N沉降是否以及如何介导这些影响,目前尚不清楚。本文在中国东北的草甸草原上进行了温室实验以检验添加狼毒(Stellera chamaejasme)凋落物和氮素对优势植物羊草(Leymus chinensis) 的生长、AMF和土壤特征的影响。结果表明,添加凋落物显著增加了羊草分株数、地上生物量和土壤速效磷(AP)浓度,并降低了AMF孢子密度。然而,凋落物与氮素的交互作用并未显著影响羊草和AMF。狼毒凋落物通过提高AP对羊草产生正效应,并结合土壤养分平衡与凋落物诱导的化感成分的变化对AMF产生负效应。另外,高氮添加能缓解土壤的氮限制并抑制凋落物分解,从而减缓凋落物对羊草和AMF的影响。上述结果表明,除了关注有毒植物对家畜的有害作用外,还应客观地、全面地评价有毒植物的生态功能;同时,氮沉降应作为预测退化草地有毒植物与可食植物的种间关系的一项重要指标。     

The interaction with arbuscular mycorrhizal fungi or Trichoderma harzianum alters the shoot hormonal profile in melon plants

Arbuscular mycorrhizal fungi (AMF) and Trichoderma harzianum are known to affect plant growth and disease resistance through interaction with phytohormone synthesis or transport in the plant. Cross-talk between these microorganisms and their host plants normally occurs in nature and may affect plant resistance. Simultaneous quantification in the shoots of melon plants revealed significant changes in the levels of several hormones in response to inoculation with T. harzianum and two different AMF (Glomus intraradices and Glomus mosseae). Analysis of zeatin (Ze), indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), jasmonic acid (JA) and abscisic acid (ABA) in the shoot showed common and divergent responses of melon plants to G. intraradices and G. mosseae. T. harzianum effected systemic increases in Ze, IAA, ACC, SA, JA and ABA. The interaction of T. harzianum and the AMF with the plant produced a characteristic hormonal profile, which differed from that produced by inoculation with each microorganism singly, suggesting an attenuation of the plant response, related to the hormones SA, JA and ethylene. These results are discussed in relation to their involvement in biomass allocation and basal resistance against Fusarium wilt.     

<Emphasis Type="Italic">Epichloë</Emphasis> exudates promote in vitro and in vivo arbuscular mycorrhizal fungi development and plant growth

Background and aims

We studied, through exudates employment, the effect of Epichloë (endophytic fungi), both independently and in association with Bromus auleticus (grass), on arbuscular mycorrhizal fungi (AMF) colonization, host and neighbouring plants biomass production and soil changes.

Methods

Through in vitro and greenhouse experiments, Epichloë endophytes effect on AMF development was evaluated. In vitro studies of exudates effect on Gigaspora rosea and Rhizophagus intraradices were performed using root or endophyte exudates. A 6-month greenhouse experiment was conducted to determine Bromus auleticus endophytic status effect and endophyte exudates role in biomass production, neighbouring plants mycorrhizal colonization and soil properties.

Results

Endophyte exudates and E+ plant root exudates promoted in vitro AMF development in the pre-infective stage of G. rosea and in carrot root culture mycelium of R. intraradices in a dose-response relationship, while control media and E- plants exudates had no effect. R. intraradices colonization and plant growth was clearly increased by endophytes and their exudates.

Conclusions

This is the first work evidencing the direct effect of Epichloë endophytes and infected plants root exudates on AMF extramatrical development. While higher levels of AMF colonization were observed in E+ plants, no clear effect was detected in neighbouring plants colonization, plant biomass or soil properties.

     

Neotyphodium Coenophialum-Infected Tall Fescue and Its Potential Application in the Phytoremediation of Saline Soils

The growth response of endophyte-infected (EI) and endophyte-free (EF) tall fescue to salt stress was investigated under two growing systems (hydroponic and soil in pots). The hydroponic experiment showed that endophyte infection significantly increased tiller and leaf number, which led to an increase in the total biomass of the host grass. Endophyte infection enhanced Na accumulation in the host grass and improved Na transport from the roots to the shoots. With a 15 g l^?1 NaCl treatment, the phytoextraction efficiency of EI tall fescue was 2.34-fold higher than EF plants. When the plants were grown in saline soils, endophyte infection also significantly increased tiller number, shoot height and the total biomass of the host grass. Although EI tall fescue cannot accumulate Na to a level high enough for it to be termed a halophyte, the increased biomass production and stress tolerance suggested that endophyte / plant associations had the potential to be a model for endophyte-assisted phytoextraction in saline soils.