Testing the Effect of Soil Heterogeneity on Arbuscular Mycorrhiza Fungi (AMF) Contribution to Plant Productivity

Most natural soils are heterogeneous and nutrient availability and soil structure change greatly over small distances. It is still unclear whether AMF are advantageous for plants under such heterogeneous soil conditions. The objective of this study was to determine whether diverse AMF community support host plant community productivity in heterogeneous soil. It was also tested whether soil heterogeneity affects plant productivity. This was carried out in a greenhouse experiment made up of two factors: soil heterogeneity and AMF richness. Soil heterogeneity was simulated by mixing three soil types (sand, field soil and organic soil) together (homogenous soil (HM)), mixing them partly (semi homogenous (SH)) or keeping the three soil types separate in three compartments within one pot (heterogeneous (HT)). AMF richness was simulated by adding no AMF, one of four different AMF species separately, or all four different AMF together. The pots were planted with a mixture of Trifolium pratense and Lolium multiflorum. There was no effect of soil heterogeneity on total plant biomass. However, the biomass of the individual plant species was greatly affected by soil heterogeneity with Lolium being the most abundant in the heterogeneous soil and Trifolium being the most abundant in the homogenous soil. Total plant biomass did not increase with AMF richness. Moreover, opposite to the hypothesis, AMF richness was not beneficial for plant productivity in a heterogenous soil environment. However, there were significant differences in plant biomass with different AMF treatments in the SH and HT treatment indicating that effects of AMF on plant productivity are influenced by soil type. These effects on yield and AMF reflect a combination of local responses to growing conditions. The results show that AMF influence on plant yield may not always be positive but is strongly dependent on ecological elasticity and environmental condition.

Effects of Two Kinds of Arbuscular Mycorrhizal Fungi (AMF) Inoculums on Cucumber Seedlings Growth

To study the effects of AMF （ arbuscular mycorrhizal fungi） ineeulums on seedling growth of cucumber, vegetable seeds were inoculated with two kinds of AMF ineculums BF （ mycorrhiza for plants） and VT （ mycorrhiza for vegetables） from Czech Republic during sowing in trays in greenhouse. The root AMF infection rates in seedlings were 49.30% and 37.65% respectively after 35 d growth. The plant height, stem diameter, fresh and dry weight of those seedlings inoculated with BF and VT were higher than that in CK. Compared with the CK, VT inoculation significantly improved the root activity, chlorophyll content and photosynthetic rate of cucumber seedlings. Comprehensive analysis showed that VT could promote seedling growth of protected cucumber.

弱光及干旱条件下AMF对切花月季光合和AsA-GSH循环的影响

旨在探究弱光及干旱条件下丛枝菌根真菌(AMF)对切花月季光合、AsA-GSH循环以及渗透调节物质的影响。盆栽条件下设置100%全光照(L1)、50%全光照(L2)2个光照处理组,80%土壤持水量(W1)和40%土壤持水量(W2)2个水分处理组,接种AMF[变形球囊霉(Glomus versiforme)+异形根孢囊霉(Rhizophagus irregularis)]及不接种对照(CK)共8个处理。结果表明,AMF能够侵染切花月季根系,显著提高切花月季生长品质。弱光和/或干旱胁迫下,与不接种对照相比,接种AMF能有效地促进切花月季叶片的净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))和水分利用效率(WUE)增加,降低细胞间隙CO_(2)浓度(C_(i));在L2W2处理条件下,与不接种对照相比,接种AMF使切花月季叶片中的抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、单脱氢抗坏血酸还原酶(MDAR)和脱氢抗坏血酸还原酶(DHAR)活性分别提高5.2%、15.4%、21.7%和35.9%;接种AMF的抗坏血酸(AsA)含量与对照处理无显著差异,还原型谷胱甘肽(GSH)含量提高8.1%,GSH/GSSG比值增加7.9%;接种AMF后切花月季丙二醛(MDA)含量显著降低,可溶性糖、可溶性蛋白和脯氨酸(Pro)含量明显增加。结论认为AMF通过维持AsA/DHA和GSH/GSSG的稳定,提高AsA-GSH循环中相关酶活性,增加切花月季叶片可溶性糖、可溶性蛋白和脯氨酸含量而降低MDA含量来适应水分和光照的变化,形成适应光照和水分条件变化的生理生态对策来改善切花月季生长品质。

The Effects of Arbuscular Mycorrhizal Fungi on Reactive Oxyradical Scavenging System of Tomato Under Salt Tolerance

The effects of arbuscular mycorrhizal fungi （AMF）, Glomus mosseae, on oxygen radical scavenging system of tomato under salt stress were studied in potted culture experiments. The response of tomato （Lycopersieon eseulentum L.） cultivar Zhongza 9 seedlings with AMF inoculation and control to salt stress （0, 0.5 and 1.0% NaCl solution, respectively） was investigated. The results showed that the salt stress significantly reduced the dry matter content of roots, stems and leaves, and also the leaf area as compared with the control treatment. However, arbuscular mycorrhizal-inoculated （AM） significantly improved the dry matter and the leaf area in the salt-stressed plants. The effect of AMF on dry matter was more pronounced in aerial bromass than in root biomass which might be due to AM colonization. The activities of SOD, POD, ASA-POD, and CAT in leaves and roots of mycorrhizal and non-mycorrhizal treatment of tomato plants were increased and had different rules under different NaCl concentrations （solution of 0, 0.5 and 1% NaCl）, but all enzymes had a rise in the beginning of treatment under salt stress conditions. The AMF did not change the rule of tomato itself under salt stress, but AMF increased these enzyme activities in different levels. The AMF treatment significantly increased SOD, POD and ASA-POD activities in leaves and roots, whereas it had little effects on CAT in root. O2- production rate and MDA content in leaves increased continuously, which showed a positive line correlation with salt stress concentration. O2- production rate and MDA content in tomato plants significantly decreased by AM treatment compared with nonmycorrhizal treatment. In conclusion, AM could alleviate the growth limitations imposed by saline conditions, and thereby play a very important role in promoting plant growth under salt stress in tomato.

神东矿区接种AMF对植物−土壤生态化学计量及养分回收的影响

矿区采煤沉陷地植被恢复和微生物复垦是打造绿色矿山的关键点。丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)和恢复植被类型对植物−枯落叶−土壤连续体的生态化学计量学特征及养分回收的影响尚不明朗,但对阐明西北干旱采煤沉陷区生态修复后养分循环和可持续发展具有重要意义。选择复垦10 a后接种AMF与对照的紫穗槐、沙棘、文冠果、欧李、野樱桃5种恢复植被及对应植被的0~10 cm土壤进行研究,旨在探明接菌和恢复植被类型对植物−枯落叶−土壤连续体碳(C)、氮(N)、磷(P)含量和生态化学计量比,养分回收率、养分限制的影响。结果表明:5种恢复植被各器官平均养分含量与全国水平相比呈现出高C、P低N的特点,土壤N的缺乏限制了枯落物分解和植物生长。冗余分析表明影响植物生态化学计量的主要土壤因子是土壤有机碳、P、土壤易提取球囊霉素并且土壤养分与叶养分回收在菌根介导下呈正相关。AMF接种提高了植物、土壤养分含量、N、P回收率和土壤碳氮比,降低了植被的氮磷比,进而缓解植物N限制,增加植物生长速率支持恢复植被重建,促进连续体养分循环。在不同人工重建植被中接菌的固氮植被紫穗槐和沙棘养分含量、稳定性及生长速率高。植物−枯落叶−土壤连续体生态化学计量及养分回收特征预测土壤氮限制沉陷区可持续生态恢复,接种AMF则促进沉陷区持续生态恢复的潜力。

宁夏沙生药用植物AMF、DSE侵染特征及DSE鉴定

为研究宁夏沙生药用植物根系丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)与深色有隔内生真菌(dark septate endophytes,DSE)的侵染特征及DSE物种多样性,在宁夏各地采集健康的黄耆、苦豆子和柠条等13种沙生药用植物的根样,显微观察AMF和DSE的侵染特征,采用形态学结合分子生物学鉴定,研究DSE物种多样性。结果表明:13种植物根系中均有AMF定植;除乳浆大戟外12种植物根系均有DSE定植;AMF定植率高于DSE定植率。在苦豆子、沙蒿、沙冬青、黄耆、柠条5种植物根系分离得到4株DSE菌株,分别是Cladosporium cladosporioides、Alternaria sp.、Aspergillus fumigatus、Paraphoma chrysanthemicola。

不同AMF菌肥对桑树“嘉陵30”生长和叶品质的影响

“嘉陵30”是我国西南地区大面积推广种植的优质果叶两用桑树(Morus alba)品种,为了研究不同丛枝菌根真菌(AMF)菌肥对其生长和桑叶品质的影响,实验添施了5种AMF菌肥,并比较桑树植株的色素含量、生长发育和叶片品质在施加前后的差异,以此筛选出适合“嘉陵30”的最佳菌肥。结果显示:(1)色素含量方面,与对照相比,施加隐类球囊霉(Paraglom occultum)菌肥的植株叶绿素b、总叶绿素和类胡萝卜素含量均显著增加,分别提高30.00%、21.96%和21.35%。(2)生长发育方面,与对照相比,施加隐类球囊霉菌肥的植株株高、基径、叶面积、叶干重、茎干重、总干重均显著增加,分别提高50.32%、21.06%、31.68%、27.25%、98.39%和39.01%。(3)叶片品质方面,与对照组相比,施加根内球囊霉(Glomus intraradices)的植株叶C、N、粗蛋白以及总氨基酸含量均显著增加,分别提高4.07%、3.94%、4.51%和7.14%,而生物碱显著降低64.30%。上述结果表明,施加隐类球囊霉菌肥在促进植株生长发育和增加生物量的积累方面效果最佳,而施加根内球囊霉菌肥在提高桑叶品质方面效果更好。

Effectivity of arbuscular mycorrhizal fungi collected from reclaimed mine soil and tallgrass prairie

We examined suitability of arbuscular mycorrhizal fungi (AMF) associated with cool-season nonnative forages on reclaimed surface-mined land in southeast Ohio for establishment of native warm-season grasses. The goal of establishing these grasses is to diversify a post-reclamation landscape that is incapable of supporting native forest species. A 16-week glasshouse study compared AMF from a 30-year reclaimed mine soil (WL) with AMF from native Ohio tallgrass prairie soil (CL). Four native grasses were examined from seedling through 16 weeks of growth. Comparisons were made between CL and WL AMF on colonized (+AMF) and non-colonized plants (–AMF) at three levels of soil phosphorus (P). Leaves were counted at 4 week intervals. Shoot and root biomass and percent AMF root colonization were measured at termination. We found no difference between WL and CL AMF. Added soil P did not reduce AMF colonization, but did reduce AMF efficacy. Big bluestem (Andropogon gerardii Vitman), Indiangrass (Sorghastrum nutans (L.) Nash), and tall dropseed (Sporobolus asper (Michx.) Kunth) benefited from AMF only at low soil P while slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners) exhibited no benefit. Establishment of tallgrass prairie dominants big blue-stem and Indiangrass would be supported by the mine soil AMF. It appears that the non-native forage species have supported AMF equally functional as AMF from a regionally native tallgrass prairie. Tall dropseed and slender wheatgrass were found to be less dependent on AMF than big bluestem or Indiangrass and thus would be useful in areas with little or no AMF inoculum.

Diversity of Arbuscular Mycorrhizal Fungi Species Associated with Soybean (Glycine max L. Merill) in Benin

Arbuscular Mycorrhizal Fungi (AMFs) could be used to sustainably improve crop yields. The present study evaluated the diversity of AMF species associated with soybean (Glycine max L. Merill) in main soybean-producing areas in Benin. Composite soil samples from 13 production areas at a rate of 04 villages per production areas were collected. A spore trapping device was set up to reveal the diversity of spores. The physical and chemical properties of the soils, the frequency and intensity of mycorrhization of roots, and the diversity of AMF spores were determined in the soil samples following trapping. As result, eight morphotypes belonging to four genera: Glomus, Acaulospora Gigaspora and Disversispora and three families: Diversisporales, Glomérales and Paraglomérales were observed. An important variability of spore densities was observed from one production areas to another with a higher abundance in the production areas of Copargo estimated at 3584 spores/100g soil. The biological diversity indexes as Shannon (0.0311), Simpson (0.0204) and Hill (0.0235), varied significantly (p < 0.05) from one production areas to another. There was significant correlation between the parameters studied, particularly between the physico-chemical parameters of the soils and between the physico-chemical parameters and the biological diversity indexes. For the mycorrhization parameters, the mycorhization frequencies did not vary from one production areas to another, unlike the intensities, which significantly varied from one production areas to another (2.31% to 24.62%). Finally, this study revealed that the physico-chemical parameters of the soils had an influence on the other parameters studied. Moreover, there were an abundance and a significant diversification of AMFs associated with soybean in the different production areas, which are influenced by certain physico-chemical soil parameters.

Effect of Inoculation with Arbuscular Mycorrhizal Fungus on Nitrogen and Phosphorus Utilization in Upland Rice-Mungbean Intercropping System

The effect of arbuscular mycorrhiza fungi （AMF） on plant growth and nutrition utilization in upland rice and mungbean intercropping system was studied. A pot experiment was conducted in the greenhouse and AMF colonization rates of rice and mungbean roots, plant nutrient contents, the ability of nitrogen fixation, and nutrient contents changed in the soil were analyzed. The results were obtained as follows： the rates of AMF colonization of rice and mungbean roots were reached to 14.47 and 92.2% in intercopping system, and increased by 4.11 and 11.95% compared with that of in monocropping; the nirtrogen contents of mungbean and rice were increased by 83.72 and 64.83% in shoots, and 53.76 and 41.29% in roots, respectively, while the contents of iron in shoot and root of mungbean were increased by 223.08 and 60.19%, respectively. In the intercropping system with inoculation of AMF, the biomass of mungbean increased by 288.8%. However, the biomass of rice was not significantly changed among all treatments with or without inoculation of AMF recorded. The number and dry weight of nodules were significantly increased either when mungbean was intercropped with rice or inoculated with AMF. When compared with that of monocropping without AMF inoculation, the contents of nitrogen, phosphorus and iron in nodules of intercropping mungbean with inoculation increased by 80.14, 69.54 and 39.62%, respectively. Additionally, intercropping with AMF inoculation significantly increased soil nitrogen content, but reduced soil phosphorus content. We concluded that upland rice-mungbean intercropping system and inoculation with AMF improved the nutrient uptake, the ability of nitrogen fixation and the growth of mungbean.

丛枝菌根真菌(AMF)对蒙古沙冬青幼苗的促生特性及作用机制

为解决蒙古沙冬青(Ammopiptanthus mongolicus)幼苗根系不发达、再生性差、移栽造林成活率低的技术难题及其资源的有效扩繁和保存,试验采用丛枝菌根真菌(AMF)不同接菌方式处理蒙古沙冬青实生幼苗根系,分析AMF对其侵染状况及植株生长和生物量的变化,根系及叶片生理特性、根际土壤酶活性变化及其与幼苗生长和生物量变化的关联性。研究旨在探讨根系菌根化作用对蒙古沙冬青幼苗的促生长及作用机制。结果表明:丛枝菌根真菌(根内根孢囊霉Rhiaophagus intraradice,摩西斗管囊霉Funneliformis mosseae)可有效侵染蒙古沙冬青幼苗根系并与其根系构建互惠共生体,不同菌种与宿主植物的亲和程度存在差异。(1)单接菌和混合接菌与未接菌(CK)相比生长量均有所提高,主要表现在植物株高(34.7%~47.3%)和根长(32.7%~72.9%)相对较大。其中混合接菌较单接菌处理显著增加了总根投影面积、总根体积、根冠比、根干重及根表面积、植株总生物量和苗木质量指数。(2)接种AMF,特别是接种R.i+F.m幼苗根系活力、根系阳离子交换量及根系可溶性蛋白含量较对照显著提升338.7%、177.2%和240.4%,根系硝酸还原酶及碱性磷酸酶活性也显著高于单一接菌(R.i、F.m)及未接菌处理。同时该处理下幼苗叶净光合速率和可溶性蛋白含量较对照显著提高237.5%和54.3%。(3)3种接菌方式均可显著提升蒙古沙冬青幼苗根际土壤脲酶、碱性磷酸酶和蔗糖酶活性,且3种土壤酶均在混合接菌时活性提升速率最为显著,分别较对照激增564.7%、145.8%和154.3%。综合以上指标分析,AMF通过侵染蒙古沙冬青根系刺激幼苗根际土壤酶的产生和分泌并促进其根系阳离子交换及活力提升,有助于增强根系代谢过程中酶促作用及蛋白等营养物质的积累,同时影响和改善了幼苗光合代谢和营养储存,从而促进沙冬青根系及幼苗生长和生物量累积。

Comparison of Arbuscular Mycorrhizal Fungal Community in Roots and Rhizosphere of Invasive Cenchrus incertus and Native Plant in Inner Mongolia,China

Plant invasions could significantly alter arbuscular mycorrhizal(AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant invasion could improve our understanding of the invasion processes. Here, we examined the AM fungal community composition both in roots and rhizosphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia by using terminal restriction fragment length polymorphism analyses(T-RFLP). The results showed that AM fungal abundance in the rhizosphere soils of C. incertus was significantly lower than that of S. viridis. The AM fungal community composition in the rhizosphere soils of the two plant species also largely differed. In general, AM fungal community structures in roots corresponded very well to that in rhizosphere soils for both plant species. The dominant AM fungal type both in invasive and native plants was T-RFLP 524 bp, which represents Glomus sp.(Virtual taxa 109 and 287). Three specific T-RF types(280,190 and 141bp) were significantly more abundant in C. incertus, representing three clusters in Glomus which also named as VT(virtual taxa) 287, 64 and 214, Rhizophagus intraradices(VT 113) and Diversispora sp.(VT 60). While the specific T-RF types,189 and 279 bp, for S. viridis, only existed in Glomus cluster 1(VT 156), were significantly less abundant in C. incertus. These results indicated that AM fungi might play an important role in the invasion process of C. incertus, which still remains to be further investigated.

油茶炭疽病发生与丛枝菌根真菌(AMF)关系研究

为应用丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)防控油茶炭疽病,探究土壤AMF与油茶炭疽病发生程度之间的关系。采用湿筛沉淀法和AMF定殖染色法探究油茶炭疽病发生样点土壤的AMF孢子密度、丰富度、多样性指数和菌根定殖率及病健植株发病率与病情指数间的关系。结果表明,病健油茶根部AMF孢子密度、定殖率具有显著差别,感病油茶土壤中AMF孢子的丰富度与多样性指数有下降趋势(P<0.05);AMF孢子密度、丰富度、定殖率与油茶炭疽病发病率和病情指数呈极显著负相关关系(P<0.01),多样性指数与油茶炭疽病发病率和病情指数呈显著负相关关系(P<0.05)。研究发现AMF孢子密度、菌根定殖率、丰富度和多样性指数越大,油茶炭疽病越轻,显示AMF对防治油茶炭疽病具有潜在应用价值。

横断山脉亚高山带几种高山栎林下丛枝菌根菌(AMF)调查

[目的]明确横断山脉亚高山带高山栎林下AMF孢子分类地位。[方法]自横断山脉亚高山带不同地段选择6个高山栎根围土壤和根系样本,对其土壤中AMF孢子利用湿筛沉淀法进行选取。利用AMF特异引物对其ITS区段18S rRNA基因进行扩增,结合形态学与分子生物学手段对其进行鉴定,构建系统发育演化树并推测其亲缘关系。[结果]四川、西藏高山栎林下土壤AMF孢子与根系克隆为类球囊霉属(Paraglomus),云南香格里拉高山栎林下土壤AMF孢子与根系克隆为球囊霉属(Glomus)。克隆结果表明:AMF能够广泛存在于高山栎组植物根系。根系苯胺蓝染色结果可见明显类似丛枝和泡囊的结构。综合高山栎土壤AMF孢子与根际AMF鉴定结果认为,高山栎林下存在大量AMF,且目前不同采样地高山栎林下根围土和根系分别仅发现一种AMF存在,提示各高山栎同时仅能与一种AMF发生共生关系。此外,高山栎林下AMF孢子在演化过程中发生分化并介于Paraglomus与Glomus的分类地位之间,且西藏、四川地区AMF与云南香格里拉地区AMF存在差异。[结论]本研究发现,自然条件下横断山脉亚高山地区高山栎林下菌塘普遍存在AMF,且云南香格里拉地区高山栎根系AM与Glomus属更接近,说明AM在长期演化过程中随地域迁移出现分化。为了解横断山脉亚高山带高山栎林下AMF的形成与演化提供理论参考。

盐胁迫下外源褪黑素和丛枝菌根真菌对月季幼苗生长生理特性的影响

【目的】盐胁迫易导致月季生长发育不良、观赏品质下降,严重影响其在高盐环境或沿海地区室外绿化应用,探究施用外源褪黑素(MT)和接种丛枝菌根真菌(AMF)对其幼苗生长、叶绿素荧光参数以及激素代谢的调控作用,解析它们促进月季适应盐胁迫的生理生化机制,对于增强月季抗盐性,扩大月季应用范围具有重要意义。【方法】以月季品种‘月月红’幼苗为试验材料,采用室内盆栽试验,设置对照(CK)、100 mol/L NaCl胁迫、根际施用MT、根际接种AMF幼套近明球囊霉(Claroideoglomus etunicatum)及其组合等8个处理,考察各处理对月季幼苗生长、叶绿素荧光参数、激素代谢及抗氧化系统的影响。【结果】(1)施用MT可以促进AMF对月季幼苗根系的侵染,提高侵染率、丛枝着生率、泡囊数和侵入点数;(2)月季幼苗株高、茎粗以及生物量等在盐胁迫下显著下降,在MT或AMF处理下均不同程度增加,而AMF+MT处理下株高、茎粗无显著变化,地上部干重、地下部干重分别显著增加24.1%和37.0%;(3)月季幼苗叶绿素含量在盐胁迫下显著下降,叶绿素荧光参数也降低,MT或AMF处理能提高盐胁迫月季幼苗叶绿素含量以及叶绿素荧光参数,AMF+MT处理则使叶绿素总量、叶绿素a/b分别增加46.2%和67.2%,PSⅡ最大光化学效率(F_(v)/F_(m))、潜在活性(F_(v)/F_(o))、实际光化学效率(ΦPSⅡ)、有效光化学量子效率(Fv'/Fm')、光化学淬灭系数(qP)分别增加4.9%、51.0%、175.0%、168.7%和92.5%,而NPQ下降42.7%;(4)在盐胁迫下,月季叶片中玉米素(ZT)、赤霉素(GA)、生长素(IAA)含量下降,而脱落酸(ABA)含量增加,MT或AMF处理有利于盐胁迫下ZT、GA、IAA含量的提高以及ABA含量的下降,AMF+MT处理后ZT、GA、IAA分别增加146.9%、116.9%、35.7%,ABA下降21.1%;(5)在盐胁迫下,抗氧化酶SOD、CAT活性增强,超氧阴离子(O_(2)^(-·))产生速率和H_(2)O_(2)累积大量增加,MT或AMF处理有助于增加抗氧化酶活性并减少O_(2)^(-·)产生速率和H_(2)O_(2)含量,而AMF+MT处理能够进一步激活SOD、CAT活性,降低O_(2)^(-·)产生速率和H_(2)O_(2)累积。【结论】接种AMF、添加MT或者AMF+MT处理均可以提高盐胁迫下月季幼苗叶绿素含量,保护叶绿素荧光系统,维持植物内源激素的平衡,激活SOD、CAT等抗氧化酶活性以及降低脂质过氧化和H_(2)O_(2)累积,以减轻盐胁迫对月季幼苗的伤害,促进月季生长,并以AMF+MT处理增强月季幼苗抗盐性的效果更佳。

广西金花茶根系丛枝菌根真菌染色方法探讨

金花茶(Camellia nitidissima)为山茶科山茶属植物,属于国家一级保护植物,具有很高的观赏价值及药用价值。但目前金花茶野生资源少,因此寻找高效的人工种植方法快速繁殖金花茶优良种苗,进而大幅度提高规模化种植金花茶的产量十分必要。丛枝菌根(arbuscular mycorrhiza,AM)真菌能显著促进植物生长发育、提高作物产量、增强植物抗逆性和抗病性,金花茶接种AM真菌,对金花茶有积极的影响。由于几乎所有的AM真菌接种试验均涉及菌根发育状况观察与侵染率测定,而目前AM侵染状况的观察测定方法种类繁多,良莠不齐,因此本研究探究一种金花茶根系AM真菌检测的最佳染色方法,以便更好地观察AM真菌对金花茶根系的侵染情况。本研究以金花茶健康植株根系为试验材料,探讨5种染色剂(苏丹红Ⅳ、酸性品红、苯胺蓝、台酚蓝、醋酸墨水)对金花茶根系AM真菌的染色效果。研究表明:5%醋酸墨水染色液的染色效果最佳,根皮层细胞内AM真菌的菌丝、泡囊、孢子等结构清晰可见,且能够明确分辨AM真菌与其他未知真菌,根的染色效果可以长久保存;利用苏丹红Ⅳ和酸性品红染色的AM真菌菌丝、泡囊与背景反差不明显,而且酸性品红的染色效果保存时间短,不利于观察;苯胺蓝和台酚蓝的染色效果略次于醋酸墨水,且价格昂贵,成本高。除醋酸墨水外,其他4种染色剂均是疑似致癌物,长期使用对操作人员的健康产生非常大的安全隐患。醋酸墨水染色操作简便、毒性低、成本低廉、染色效果极佳,适用于金花茶根系AM真菌的染色和制片观察。本研究结果可为今后金花茶菌根种苗的应用提供新的思路。

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

为研究设施生态系统丛枝菌根(Arbuscularmycorrhiza,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IlluminaMiSeq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。

AMF对低温胁迫下黄瓜幼苗生长和叶片抗氧化系统的影响

【目的】研究丛枝菌根真菌(arbuscular mucorrhiz fungi,AMF)对低温胁迫下黄瓜(Cucumis sativusL.)幼苗生长和抗氧化酶活性等生理指标的影响。【方法】以黄瓜品种‘津春2号’为试材,利用人工气候箱进行低温处理(昼/夜,15/10℃),研究低温胁迫下接种AMF对黄瓜幼苗生长、电解质渗透率、根系活力和叶绿素、丙二醛(MDA)、可溶性蛋白质含量及过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性的影响。【结果】与低温胁迫的未接菌对照相比,接种AMF可以使低温胁迫下黄瓜幼苗的株高增长量、茎粗增长量、地上部和地下部鲜质量的增长量、地上部和地下部干质量的增长量均显著提高,可溶性蛋白含量增加10.24%,根系活力提高178.32%,POD、SOD、CAT活性分别提高57.63%、6.72%和35%,MDA含量和电解质渗透率分别降低11.05%和16.08%。【结论】接种AMF可通过促进低温胁迫下黄瓜幼苗叶片可溶性蛋白的大量积累和抗氧化酶活性的提高,来降低膜脂过氧化水平,从而增强黄瓜幼苗对低温胁迫的适应性。

干旱胁迫下AMF对云南蓝果树幼苗生长和光合特征的影响

采用盆栽试验与称重控水法,将土壤相对含水量分别控制在田间最大持水量的100%、91.68%、82.85%、60.00%、41.86%和21.28%,并在这6个不同的土壤相对含水量条件下,分别设添加苯菌灵(杀真菌剂)(低AMF)和不添加苯菌灵(高AMF)处理,研究干旱胁迫下AMF对极小种群野生植物云南蓝果树幼苗生长和光合特征的影响,揭示云南蓝果树濒危的微生物学机制,为云南蓝果树保护措施的制定与实施奠定基础。结果表明,添加苯菌灵处理显著降低了不同水分条件下的AMF侵染率,说明试验中AMF处理的实生苗在生长和光合特征上的差异是苯菌灵处理下侵染率下降导致的;随着干旱胁迫的加剧,云南蓝果树幼苗的根部AMF侵染率显著降低、叶面积等生长指标和净光合速率(Pn)等光合参数都发生显著变化;高AMF处理可以显著增加水分充足和轻度干旱胁迫条件下云南蓝果树幼苗的大部分生长指标和光合参数,而对重度胁迫下的云南蓝果树幼苗没有显著影响,说明重度干旱胁迫对其影响大于AMF的影响;另外,整合了可塑性指数分析和隶属函数分析两种方法对其抗旱性进行评价,云南蓝果树幼苗基本上无法通过调节形态和光合能力来适应水分环境的变化,但是高AMF处理可使云南蓝果树幼苗具有较强的可塑性和更强的抗旱性。实验结果为云南蓝果树的科学保育及种苗繁育提供了理论依据。

接种丛枝菌根真菌(AMF)对施磷石膏云烟87的生长以及砷污染的影响

【目的】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)能够促进作物养分的吸收及生长,且对土壤砷污染有一定的抗性。磷石膏(phosphogypsum,PG)因含有丰富的磷、硫等养分可以为作物生长提供必要的养分,同时也可能带来砷污染的风险。【方法】为了探讨接种AMF对云烟87生长的影响以及磷石膏农用可能引起的砷污染风险,通过盆栽模拟试验研究了不同PG添加量(0和40 g/kg以PG0、PG40表示)和接种不同AMF[不接种None mycorrhizal(NM)、接种G.mosseae丛枝菌根真菌(GM)、接种G.aggregatum丛枝菌根真菌(GA)]对云烟87苗期生长及其磷、硫、砷吸收的影响。【结果】试验结果表明:无论接种与否,PG40处理的云烟87植株磷含量、吸收量及吸收效率均显著增加,其地上部硫含量及吸收量也显著增加;除NM处理外,添加PG均显著增加了云烟87根系的硫含量、硫吸收量及吸收效率,并显著增加了其植株的生物量。相同PG添加水平下,与NM处理相比,接种GM显著增加了云烟87根系的磷、硫吸收效率和植株的磷、硫含量及吸收量,另外,GM处理显著降低了其地上部砷含量及吸收量但显著增加了其植株的磷砷吸收比。在PG0处理下,接种GA显著增加了云烟87植株的磷含量及吸收量,并显著增加了其地上部硫含量及吸收量。在PG40处理下,接种GA显著增加了云烟87根系的硫含量和吸收量以及植株的生物量。无论是否添加PG,接种GA不同程度地降低了云烟87地上部砷含量和吸收量从而增加了其地上部的磷砷吸收比。【结论】在所有复合处理中,以添加磷石膏40 g/kg和接种GM对云烟87生长的促进效果较好,对施用磷石膏造成的砷污染有一定程度的抵御作用。