设施栽培黄瓜根内AMF与DSE结构发育特征

本研究旨在观察和测定设施栽培黄瓜根系丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)与暗隔内生真菌(dark septate endophytic fungi,DSE)形态结构,明确其发育特征,为进一步探索AMF与DSE相互作用奠定基础。自山东莱阳、寿光和莱西等设施蔬菜主产区选择黄瓜Cucumis sativus样地,从不同连作年限、黄瓜生育期和土层深度分别采集黄瓜根系和根区土壤;观察根内AMF与DSE形态特征、测定AMF和DSE侵染数量、分析AMF或DSE侵染发育数量与黄瓜根结线虫Meloidogyne incognita病害的相关性。从黄瓜根系中可观察到典型的AMF泡囊、疆南星型(Arum,A)与重楼型(Paris,P)丛枝结构、DSE菌丝和微菌核。以黄瓜结果中期根系AMF和DSE侵染率最高,分别为57%和28%,苗期最低,分别为18%和8%;初花期的丛枝为P型,苗期和结果中期则为A型+P型。连作7年和7–10年的黄瓜根内丛枝为A型+P型,AMF和DSE的侵染率均分别显著高于连作10年的侵染率,连作10年的丛枝为A型。黄瓜根系以0–15cm土层中AMF侵染率最高(29%),丛枝为P型;以30cm的侵染率最低(12%),丛枝为A型;15–30cm土层的为A型+P型。AMF P型着生率、P/A比率和DSE侵染率分别与根结线虫病的为害程度具有相关性。研究结果还表明黄瓜根系AMF侵染率与DSE侵染率呈显著正相关关系。     

入侵植物与本地植物互作对丛枝菌根真菌AMF侵染率的影响

外来植物成功入侵与菌根共生体存在着密不可分的关系,丛枝菌根真菌（AMF）侵染率是反映其侵染植物情况的重要指标,影响侵染率的因素很多,但是入侵植物与本地植物互作对AMF侵染率的影响目前还不清楚。因此,本研究以外来入侵植物黄顶菊Flaveria bidentis、豚草Ambrosia artemisiifolia、三叶鬼针草Bidens pilosa和本地植物狗尾草Setaria viridis、黄香草木犀Melilotus officinalis、藜Chenopodium album为研究对象,设置入侵植物单种处理、本地植物单种处理、每种入侵植物分别与本地植物两两混种处理以及每种入侵植物同时与所有本地植物混种处理,观察测定不同处理下入侵植物与本地植物根系丛枝、泡囊、菌丝及总侵染率,比较研究本地植物种类变化对入侵植物和本地植物根系AMF侵染率的影响,以及3种入侵菊科植物对本地植物AMF侵染率的影响规律是否一致。结果表明,与入侵植物单种相比,除豚草与藜、豚草同时与3种本地植物混种两个处理中,豚草根系的AMF菌丝及总侵染率显著增加外,其余所有处理中入侵植物总侵染率均无显著差异;与狗尾草或黄香草木犀单种相比,每种入侵植物同时与所有本地植物混种处理中,本地植物狗尾草和黄香草木犀根系上的AMF菌丝及总侵染率均显著降低,即随本地植物种类数目的增加,对本地植物根系的菌丝及总侵染率存在显著抑制作用,而对入侵植物无显著影响。     

暖季型草坪草AMF 侵染与孢子密度季节动态研究

以广州地区常见暖季型草坪草(地毯草Axonopus compressus、狗牙根Cynodon dactylon、结缕草Zoysia japonica)为研究对象, 通过测定植物根系AMF 侵染率、根际土壤AMF 孢子密度以及土壤理化性质, 探讨AMF 侵染率和孢子密度的季节动态变化特征, 以及与土壤理化性质之间的关系。结果表明: (1)三种草坪草的根系AMF 侵染以菌丝侵染为主, 总体表现为夏季最高, 秋季和冬季次之, 春季最低, 囊泡侵染率较低, 很少丛枝侵染; (2)季节对根际土壤AMF 孢子密度有一定的影响, 草坪草根际土壤孢子密度最大值多出现在夏季或冬季, 而春季和秋季则较低; (3)对于土壤因子, AMF 菌丝侵染率与土壤有机质含量成极显著正相关, 而囊泡侵染率与电导率成显著正相关, 与全氮和全磷成极显著负相关; 对于气候因子, AMF 总侵染率和菌丝侵染率均与月均气温和月均降水成极显著正相关。     

丛枝菌根真菌对豆科作物生长和生物固氮及磷素吸收的影响

本研究以大豆为材料,采用盆栽和田间试验,探讨丛枝菌根真菌(AMF)对豆科作物生长的影响。盆栽试验设置了接种(+AMF)和不接种(-AMF)丛枝菌根真菌处理,田间试验设置了AMF菌丝非限制与限制处理。盆栽试验结果表明: 接种AMF显著提高了大豆地上部生物量(16.5%)和大豆根瘤数(131.4%),地上部磷含量、磷吸收量、氮含量和氮吸收量也显著增加。田间试验中,AMF菌丝非限制处理下大豆的地上部生物量、根系生物量、根瘤数量分别比限制处理下显著提高了123.6%、61.5%和212.5%,地上部和根系磷吸收量、氮含量、氮吸收量均显著高于限制处理,大豆根际土壤速效氮和有效磷含量也均显著高于限制处理。本研究可为进一步认识豆科作物与AMF的共生关系及田间磷肥高效利用提供理论参考。     

丛枝菌根真菌对入侵植物南美蟛蜞菊生长及竞争力的影响

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)能促进植物的养分吸收及生长发育。入侵中国华南地区的外来入侵植物南美蟛蜞菊(Wedelia trilobata)常分布于养分匮乏的荒地,却能迅速生长并排挤本地植物而快速扩张领地。【目的】探究丛枝菌根真菌是否促进南美蟛蜞菊的生长与竞争能力。【方法】采用南美蟛蜞菊及其同属本地植物蟛蜞菊(Wedelia chinensis)的盆栽对比控制试验,并设置接种及不接种AMF变形球囊霉(Glomus versiforme)、不同磷营养水平以及单种或混种的种植方式3种处理对两种植物的生长及竞争能力进行比较。【结果】AMF均能侵染上述两种植物,并且AMF对南美蟛蜞菊根系的侵染率显著高于其对蟛蜞菊根系的侵染,尤其是在低磷水平下南美蟛蜞菊的菌根侵染率更高,而且AMF的侵染显著促进了低磷水平下南美蟛蜞菊的生长及其对蟛蜞菊的竞争能力。【结论】丛枝菌根真菌能够促进南美蟛蜞菊的生长,增强其对本地植物的竞争优势,该效应很可能对外来植物南美蟛蜞菊的成功入侵产生一定的作用。     

丛枝菌根真菌侵染率对喀斯特坡地坡位与灌木物种的响应

明确丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)侵染率对喀斯特坡地坡位与物种的响应及其关键影响因子，是合理利用土壤AMF促进喀斯特植被恢复的前提。该研究在充分调查喀斯特峰丛洼地典型灌丛坡地环境背景信息的基础上，采用曲利苯蓝染色-镜检法检测并计算典型灌木黄荆(Vitex negundo)、红背山麻杆(Alchornea trewioides)和火棘(Pyracantha fortuneana)根系AMF侵染频度、侵染强度和丛枝丰度等侵染率参数。结果表明：(1)相同坡位火棘的侵染频度、侵染强度和丛枝丰度均显著低于红背山麻杆和黄荆；下坡位黄荆和火棘的侵染强度均高于中、上坡位，而中坡位红背山麻杆的丛枝丰度显著高于上、下坡位(P<0.05)。(2)物种显著影响AMF侵染频度、侵染强度和丛枝丰度，坡位显著影响AMF侵染强度，物种与坡位的交互作用仅对AMF丛枝丰度有显著影响(P<0.05)。(3)影响AMF侵染率的关键土壤因子是土壤深度和全钾含量(P<0.05)。因此，合理利用土壤AMF促进喀斯特地区植被恢复需要考虑地形与物种的选择，并应注重兼...     

低pH对番茄幼苗菌根丛枝形成和磷营养功能的影响

以番茄Solanum lycopersicum为宿主,在pH 4.5和pH 6.5条件下分别接种3种丛枝菌根真菌(AMF),即根内球囊霉Rhizophagus irregularis、珠状巨孢囊霉Gigaspora margarita和脆无梗囊霉Acaulospora delicata,探讨低pH对AMF在根系中的丛枝形成和功能的影响。结果表明,低pH能够显著抑制AMF对根系的侵染以及丛枝的形成;3个菌种之间存在差异,表现为珠状巨孢囊霉的侵染强度最高,根内球囊霉的丛枝丰度对低pH最敏感;AMF显著增加番茄的生物量,降低其根冠比;番茄在pH 6.5的菌根依赖性低于在pH 4.5的对应值,对根内球囊霉的菌根依赖性最低;低pH对碱性磷酸酶(ALP)活性的影响与根系侵染有相似的模式;AMF显著提高地上部磷含量,增强根系LePT4的表达,但pH的影响并不显著。以上结果表明,低pH对AMF与植物共生关系的建立和维持有一定的抑制作用,低pH胁迫条件下AMF的促生作用更大,不同AMF菌种/菌株提高植株低pH抗性的能力存在差异。     

福建红树林植物丛枝菌根侵染研究

2010年5月和12月,对福建沿海3个红树林生长区(洛阳江、九龙江口、漳江口)的红树林植物丛枝菌根（AM）侵染状况进行研究。结果表明：（1）红树林生长区中6种植物根内均发现AMF侵染结构,其中桐花树、秋茄、鱼藤和芦苇的丛枝为Arum（疆南星）型;（2）6种植物的丛枝菌根侵染率差异较大,老鼠簕的侵染率最高,鱼藤最低;（3）桐花树和秋茄的丛枝菌根侵染率呈显著差异,而其在不同生长区之间无差异;（4）桐花树和秋茄的丛枝菌根侵染率在不同时间呈显著差异,而钝草的丛枝菌根侵染率在不同时间的差异不显著。     

低pH影响丛枝菌根真菌丛枝发育和磷的吸收

以番茄Solanum lycopersicum为寄主植物,在pH 3.7、pH 4.5、pH 5.5和pH 6.5条件下接种根内根孢囊霉Rhizophagus intraradices,分别在培养4周和7周取样测定低pH对丛枝菌根真菌(AMF)丛枝发育和磷吸收利用的影响。结果表明,当pH低于5.5时,低pH显著抑制AMF对根系的侵染和丛枝的形成,且抑制效应随pH的降低而增强;与侵染率相比,丛枝丰度随土壤pH的降低而降低的幅度更大;低pH显著降低了植株生物量;与不接种处理相比,接种AMF显著提高植株生物量;相关分析表明,在菌根侵染指标中丛枝丰度与植株生长相关性最高;方差分解分析表明,pH对植株生物量的贡献率(88%和77%,两次取样)大于AMF的贡献率(5%和8%,两次取样);低pH对碱性磷酸酶活性的影响与根系侵染有相似的趋势;AMF能显著提高地上部P浓度,而低pH显著降低地上部P浓度以及根系中LePT3、LePT4和LePT5的表达。这些结果表明,低pH对AMF与植物的共生关系有显著的抑制作用,其中对丛枝的形成与功能的抑制效应最大。     

AM真菌与镉互作影响桑生长和无机元素吸收转运

为评价Cd胁迫下接种AM真菌(AMF)对减轻桑树Cd毒害及Cd迁移规律的影响,采用了分室培养法开展试验。在菌根室种植无菌桑苗并接种AMF(Gigaspora rosea),菌丝室设置兼菌丝收集器功能的Cd陷阱。陷阱中的Cd处理浓度为0、5、20、40mg/kg,菌根室每室种植3株桑苗,6个重复,对照不接种AMF。培养60d后检测桑苗的菌根侵染率、不同部位的生长量、AMF菌丝生物量、4种矿质营养元素组分及Cd在AMF菌丝体和桑株中的定位及转运情况。结果表明:在0–40mg/kg的Cd处理下,不接种AMF处理的对照桑,其菌根侵染率、AMF菌丝生物量以及镉含量都为0。接种AMF处理中,当Cd<5mg/kg时,桑苗菌根侵染率、AMF菌丝生物量、桑苗鲜生物量、枝叶中N、K、Ca、Mg以及根系N、K、Ca矿质元素的积累都有促进作用,在5mg/kg时促生效果最佳;当Cd>5mg/kg时,随着Cd浓度的升高,桑苗菌根侵染率、AMF菌丝生物量、桑苗鲜生物量、枝叶中N、K、Ca、Mg以及根系N、K、Ca矿质元素的积累都受到渐强的抑制;陷阱中Cd浓度高低与根系中Mg元素的吸收量之间显著负相关;接种AMF可以显著提高桑株生物量和矿质营养的积累;Cd主要集中在桑苗的根部,Cd处理浓度与AMF菌丝体中以及桑株中的Cd含量均显著正相关;Cd在菌根桑苗中的迁移率(<9%)和不同部位(根-茎、根-叶)的转移系数(<0.1)都极其低。结果证明:Cd胁迫对桑苗的菌根侵染率、营养生长、AMF菌丝生长和矿质吸收(除Mg外)都存在低促高抑的剂量效应;AMF对Cd胁迫有一定的抗性,接种AMF显著促进植物的生长以及矿质营养元素的吸收和转运;重金属Cd在菌根桑中的分布、迁移是不均匀的,具有一定的独特性。     

干旱条件下接种AM真菌对小马鞍羊蹄甲幼苗根系的影响

为了探讨岷江干旱河谷丛枝菌根真菌(AMF)对寄主植物幼苗根系的影响,通过接种购买的AMF摩西球囊霉菌(Funneliformis mosseae)到优势乡土灌木小马鞍羊蹄甲(Bauhinia faberi var.microphylla)幼苗,在重度、中度和轻度干旱条件下培养3个月,研究不同干旱条件下AMF对幼苗根系形态特征、结构特征、功能性状的影响。方差分析结果表明:(1)3种干旱胁迫条件下,接菌均显著增加了幼苗的根总长、根表面积、根分枝数、根尖数(P0.001),在中度胁迫和轻度胁迫下,接菌显著促进根鲜重、根体积的增加(P0.001),轻度胁迫条件下接菌幼苗的根鲜重、根总长、根表面积、根体积、根尖数最高并显著高于其它处理,但接菌与未接菌的根平均直径之间没有显著差异;(2)接菌幼苗根系趋向于叉状分支结构,在重度胁迫时,叉状分支趋势更显著(P0.001);(3)接菌幼苗的根比例都显著小于未接菌的,但幼苗比根长不存在显著差异。相关分析结果表明:菌根侵染率与根鲜重、根总长、根表面积、根体积、根分枝数、根尖数呈极显著正相关(P0.001),与拓扑指数、根比例呈极显著负相关(P0.001)。研究表明,在干旱条件下,AMF虽然没有提高生长初期的根系的吸收效率,但接种AMF显著影响幼苗根系形态特征和结构特征,更利于植物适应干旱环境,并且AMF对幼苗根系的促生作用随着干旱胁迫程度减轻而提高。     

Effect of edaphic factors and seasonal variation on spore density and root colonization of arbuscular mycorrhizal fungi in sugarcane fields

Sugarcane fields in 14 different study sites were analyzed for the presence of different arbuscular mycorrhizal fungal (AMF) spores. A total of 23 AMF species representing four genera were identified, among which Glomus fasciculatum and G. mosseae were the dominant species. The mean spore density in the root-zone soils of sugarcane plants varied from 119 to 583 per 100 g of soil, and the mean percentage root colonization varied from 60 to 89 %. A study of the effect of edaphic factors on AM spore density and percentage root colonization revealed a positive correlation between pH and AMF spore density and root colonization and a negative correlation between electrical conductivity, nitrogen, and phosphorus. A positive correlation was observed between AMF spore density and root colonization. Season was also found to play a vital role in determining AMF spore density and percentage root colonization, with high spore density and root colonization observed during the summer season and lower spore densities and root colonization during the winter season.     

Chemical defense,mycorrhizal colonization and growth responses in <Emphasis Type="Italic">Plantago lanceolata</Emphasis> L.

Allelochemicals defend plants against herbivore and pathogen attack aboveground and belowground. Whether such plant defenses incur ecological costs by reducing benefits from plant mutualistic symbionts is largely unknown. We explored a potential trade-off between inherent plant chemical defense and belowground mutualism with arbuscular mycorrhizal fungi (AMF) in Plantago lanceolata L., using plant genotypes from lines selected for low and high constitutive levels of the iridoid glycosides (IG) aucubin and catalpol. As selection was based on IG concentrations in leaves, we first examined whether IG concentrations covaried in roots. Root and leaf IG concentrations were strongly positively correlated among genotypes, indicating genetic interdependence of leaf and root defense. We then found that root AMF arbuscule colonization was negatively correlated with root aucubin concentration. This negative correlation was observed both in plants grown with monocultures of Glomus intraradices and in plants colonized from whole-field soil inoculum. Overall, AMF did not affect total biomass of plants; an enhancement of initial shoot biomass was offset by a lower root biomass and reduced regrowth after defoliation. Although the precise effects of AMF on plant biomass varied among genotypes, plants with high IG levels and low AMF arbuscule colonization in roots did not produce less biomass than plants with low IG and high AMF arbuscule colonization. Therefore, although an apparent trade-off was observed between high root chemical defense and AMF arbuscule colonization, this did not negatively affect the growth responses of the plants to AMF. Interestingly, AMF induced an increase in root aucubin concentration in the high root IG genotype of P. lanceolata. We conclude that AMF does not necessarily stimulate plant growth, that direct plant defense by secondary metabolites does not necessarily reduce potential benefits from AMF, and that AMF can enhance concentrations of root chemical defenses, but that these responses are plant genotype-dependent.     

Arbuscular mycorrhizal fungi benefit from 7 years of free air CO2 enrichment in well-fertilized grass and legume monocultures

Rising atmospheric carbon dioxide partial pressure (pCO₂) and nitrogen (N) deposition are important components of global environmental change. In the Swiss free air carbon dioxide enrichment (FACE) experiment, the effect of altered atmospheric pCO₂ (35 vs. 60 Pa) and the influence of two different N‐fertilization regimes (14 vs. 56 g N m^?2 a^?1) on root colonization by arbuscular mycorrhizal fungi (AMF) and other fungi (non‐AMF) of Lolium perenne and Trifolium repens were studied. Plants were grown in permanent monoculture plots, and fumigated during the growth period for 7 years. At elevated pCO₂ AMF and non‐AMF root colonization was generally increased in both plant species, with significant effects on colonization intensity and on hyphal and non‐AMF colonization. The CO₂ effect on arbuscules was marginally significant (P=0.076). Moreover, the number of small AMF spores (≤100 μm) in the soils of monocultures (at low‐N fertilization) of both plant species was significantly increased, whereas that of large spores (>100 μm) was increased only in L. perenne plots. N fertilization resulted in a significant decrease of root colonization in L. perenne, including the AMF parameters, hyphae, arbuscules, vesicles and intensity, but not in T. repens. This phenomenon was probably caused by different C‐sink limitations of grass and legume. Lacking effects of CO₂ fumigation on intraradical AMF structures (under high‐N fertilization) and no response to N fertilization of arbuscules, vesicles and colonization intensity suggest that the function of AMF in T. repens was non‐nutritional. In L. perenne, however, AM symbiosis may have amended N nutrition, because all root colonization parameters were significantly increased under low‐N fertilization, whereas under high‐N fertilization only vesicle colonization was increased. Commonly observed P‐nutritional benefits from AMF appeared to be absent under the phosphorus‐rich soil conditions of our field experiment. We hypothesize that in well‐fertilized agricultural ecosystems, grasses benefit from improved N nutrition and legumes benefit from increased protection against pathogens and/or herbivores. This is different from what is expected in nutritionally limited plant communities.     

Fungal root symbionts and their relationship with fine root proportion in native plants from the Bolivian Andean highlands above 3,700?m elevation

Here, we examined the colonization by fungal root symbionts in the cultivated Andean grain Chenopodium quinoa and in 12 species that dominate plant communities in the Bolivian Altiplano above 3,700 m elevation and explore for the possible relationships between fungal colonization and fine root proportion. The 12 most abundant species in the study area were consistently colonized by AMF and DSE. In contrast, the annual Andean grain C. quinoa showed negligible or absence of mycorrhizal fungi colonizing roots. On the other hand, C. quinoa, Junelia seriphioides and Chersodoma jodopappa were infected to a varying degree by the root pathogen Olpidium sp. We observed no relationship between AMF and DSE colonization and proportion of fine roots in the root system, but instead, the ratio between DSE and AMF colonization (ratio DSE/AMF) negatively related with proportion of fine roots. Our findings support the hypothesis regarding the importance of DSE at high altitudes and suggest a functional relationship between the rate of DSE/AMF and proportion of fine roots. The colonization by the root pathogen Olpidium sp. in C. quinoa deserves further study since this Andean grain is increasingly important for the local economy in these marginal areas.     

Growth and Arbuscular Mycorrhizal Fungal Colonization of Two Prairie Grasses Grown in Soil from Restorations of Three Ages

I compared growth and arbuscular mycorrhizal fungal (AMF) colonization of two prairie grasses (Wild rye [Elymus canadensis] and Little bluestem [Schizachyrium scoparium]), an early‐ and a late‐dominating species in prairie restorations, respectively, grown in soil from restored prairies of differing age, soil characteristics, and site history. There were no consistent patterns between restoration age and soil inorganic nutrients or organic matter. The oldest restoration site had higher soil mycorrhizal inoculum potential (MIP) than 2‐ and 12‐year‐old restorations. However, MIP did not translate into actual colonization for two species grown in soils from the three restorations, nor did MIP relate to phosphorus availability. There were significant differences in root mass and colonization among Wild rye plants but not among Little bluestem plants grown in soils from the three restorations. Wild rye grown in 2‐year‐old restoration soil had significantly higher AMF colonization than when it was grown in soils from the 12‐ and 17‐year‐old restorations. Wild rye grown in 2‐year‐old restoration soil also had higher colonization than Little bluestem grown in 2‐ and 12‐year‐old restoration soils. Little bluestem had no significant correlations between shoot biomass, root biomass or colonization, and concentrations of soil P, total N, or N:P. However, for Wild rye, total soil N was positively correlated with root mass and negatively correlated with colonization, suggesting that in this species, mycorrhizae may affect N availability. Collectively, these results suggest that soil properties unrelated to restoration age were important in determining differences in growth and AMF colonization of two species of prairie grasses.     

Distribution of arbuscular mycorrhizal fungi in marshy and shoreline vegetation of Deepar Beel Ramsar Site of Assam,India

Arbuscular mycorrhizal fungal (AMF) symbiosis was thought to be rare in wetland plant roots, although several recent studies suggested that this association might be important in wetland ecosystems. In this research work we have studied the distribution of AMF in the marshy and shoreline vegetation of Deepar Beel Ramsar site of Assam, India. The study reveals the percentage of mycorrhizal colonization in the roots of different plant species which were observed from 20.89 to 86.47% and particularly found larger among the members of the family Poaceae. The Vetiveria zizanioides L. from the family Cyperaceae showed the highest (86.47%) percentage of root colonization, however, only one plant species viz. Scirpus lateriflorus Gmel. from the same family was found to be nonmycorrhizal. The rhizospheric soil samples of most of the plant species were found to be dominated by Glomus morphotypes. All total 18 AMF morphotypes were recorded which comprises four genera viz. Glomus (66.67%), Acaulospora (16.66%), Gigaspora (11.11%) and Scutellospora (5.56%). The observation of diversity of AMF in 25 different plant species among the wetland plants gives a glimpse of AMF diversity and their host selectivity in the said ecosystem.     

Differential benefits of arbuscular mycorrhizal and ectomycorrhizal infection of Salix repens

 The functional significance of arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) for Salix repens, a dual mycorrhizal plant, was investigated over three harvest periods (12, 20 and 30 weeks). Cuttings of S. repens were collected in December (low shoot P) and March (high shoot P). Glomus mosseae (an arbuscular mycorrhizal fungus, AMF) resulted in low AM colonization (<5%), but showed large short-term (<12 weeks) effects on shoot growth and root length. Hebeloma leucosarx (an ectomycorrhizal fungus, EcMF) resulted in high EcM colonization (70%), but benefits occurred over a longer term (>12 weeks). Furthermore, G. mosseae colonization resulted in higher shoot P uptake, shoot growth, root growth and response duration for S. repens collected in December than for those collected in March, whereas with H. leucosarx and the non-mycorrhizal treatment there were no differences between cuttings collected on different dates. Low AMF colonization was effective in the short term for cuttings at both collecting dates. Low AMF colonization of S. repens occurred irrespective of the amount of AMF inoculum used. The intensities and relative amounts of AMF structures in S. repens and Trifolium repens were compared over three harvest periods (12, 20 and 30 weeks) to assess plant species effects on AM colonization patterns. Accepted: 13 October 2000