水分胁迫下菌根菌接种对蔗叶活性氧代谢的影响

在室内水泥池以预接种主能苗移栽的方法，研究菌菌漏斗孢球囊霉（Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ）和紫色马勃（Ｃａｌｖａｔｉａ Ｌｉｌａｃｉｎａ）对甘蔗抗旱性的影响。结果表明，菌根菌接种后降低了蔗叶水分胁迫下的活性氧（Ｏ２＾－）产生速率，提高了超氧物歧化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）活性和谷胱甘肽（ＧＳＨ）的含量，活性氧清除能力增强，减少了活氧的积累及由此引发的膜脂过氧化，延缓了质膜透性的增加和膜结合     

NO-3胁迫下K+、Ca2+对黄瓜幼苗膜质过氧化及活性氧清除酶系统的影响

通过水培试验探讨了NO^-₃胁迫下K⁺、Ca²⁺对黄瓜幼苗膜质过氧化及活性氧清除酶系统的影响。结果表明，在相同NO^-₃浓度胁迫7d后， Ca²⁺浓度越大，膜脂过氧化产物丙二醛(MDA)含量越高，而K⁺浓度越大，电解质相对渗透率越高，由此说明K⁺、Ca²⁺对细胞膜造成伤害的机理不同。黄瓜幼苗活性氧清除酶系统对K⁺、Ca²⁺的响应亦不同，在一定程度上，K⁺和Ca²⁺ 可提高SOD、POD和CAT活性，保护植物免受自由基伤害，继而可增强植物对逆境的适应能力。     

低温胁迫对圆叶决明的伤害及施用Ca肥防护效果的研究

圆叶决明在0℃低温下分别胁迫6、12、18、24 h后,叶片叶绿素总量较对照(25℃)下降21.89%、26.04%、28.16%、29.31%,可溶性蛋白质含量、H₂O₂含量和·O^-₂净产生速率随胁迫时间增加,活性氧清除酶SOD的活性随胁迫时间先上升后下降。施Ca²⁺处理可明显降低圆叶决明叶片·O^-₂净产生速率、H₂O₂含量和细胞质膜的电解质渗透率,同时提高了叶绿素含量和抑制活性氧的产生,其中以0.5 mmol/L浓度的CaCl₂处理效果为最佳,说明Ca²⁺对低温胁迫下圆叶决明的膜结构起有效的保护作用。     

La(NO3)3 对盐胁迫下黑麦草幼苗生长及抗逆生理特性的影响

为探讨稀土元素镧(La)对牧草盐胁迫伤害的缓解作用, 采用水培法研究了叶面喷施20 mg·L^-1La(NO₃)₃ 对NaCl 胁迫下黑麦草幼苗生长及其抗逆生理特性的影响。结果表明: 盐胁迫显著抑制黑麦草幼苗的生长, 提高叶片电解质渗漏率及丙二醛(MDA)、O₂^- 和H₂O₂ 含量, 其作用随盐浓度的增大而增强。超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(AsA)、谷胱甘肽(GSH)、可溶性蛋白质、脯氨酸含量随盐浓度增大呈先升后降趋势, 可溶性糖和Na⁺/K⁺比逐渐增大, 质膜H⁺-ATP 酶活性逐渐降低, 过氧化物酶(POD)活性及POD 同功酶数量表达增强。喷施La(NO₃)₃ 处理可降低盐胁迫下黑麦草幼苗叶片的O₂^- 和H₂O₂ 含量, 提高SOD、CAT、POD、APX 和质膜H⁺-ATP 酶的活性及POD 同功酶的表达, 使AsA、GSH、可溶性蛋白质、可溶性糖和游离脯氨酸含量及幼苗生物量增加, Na⁺/K⁺比降低。表明La(NO₃)₃ 可通过提高抗氧化系统的活性和积累渗透溶质减轻盐胁迫伤害, 从而提高黑麦草的耐盐性。     

真菌对桉树植株的生理影响

在苗圃接种试验基础上，对桉树植株营养的吸收生理，根系活力进行了研究，根系显微观察表明，真菌组合在桉树根系上形成了混合菌根，即：PG[彩色豆马勃（Pisolithus tinctoriux)X苏格兰球囊霉（Glomus caledonium)]。接种菌根菌对桉树植株营养生理产生显著影响。接种组合PG不仅促进植株对N、P、K和B的吸收，还有利于提高苗木的根系活力和ABA的含量。     

有机物料还田对冬小麦农田土壤温室气体排放影响的研究

探讨有机物料还田对冬小麦田温室气体排放特性的影响,对提高经济效应和环境效应有积极意义。本研究应用静态箱-气相色谱法对秸秆还田（J）、秸秆还田+牛粪（JF）和秸秆还田+菌渣（JZ）3种有机物料还田下分别施氮肥243 kg （N）·hm^-2（减氮10%,N1）、216 kg （N）·hm^-2（减氮20%,N2）对冬小麦农田N₂O、CO₂和CH₄的排放通量进行监测,探讨了不同施肥措施对麦田温室气体累积排放量、增温潜势的影响。试验期间同步记录每项农事活动机械燃油量、施肥量和灌溉量,测定产量,地上部生物量,估算农田碳截留。结果表明,冬小麦农田土壤N₂O和CO₂是排放源,是CH₄的吸收汇,氮肥施入、灌溉以及强降水促进了土壤N₂O和CO₂的生成,却弱化了CH₄作为大气吸收汇的特征。牛粪+秸秆（JF）处理N₂O和CO₂排放总量最高,分别为3.5 kg （N₂O-N）·hm^-2和19 689.67 kg （CO₂-C）·hm^-2,但CH₄的吸收值最大,为5.33 kg （CH₄-C）·hm^-2,均显著高于菌渣+秸秆（JZ）和秸秆（J）处理（P<0.05）;各处理N₂O和CO₂的总量随施氮量的增加呈升高趋势,CH₄的总量随施氮量的增加而呈降低趋势。JFN2、JN2和JZN2处理农田综合增温潜势（GWP）均为负值,表明有机物料还田且减氮20%条件下农田生态系统为大气的碳汇,麦季净截留碳1 038~2 024 kg·hm^-2,其他处理GWP值均为正。JZN2处理小麦产量为8 061 kg·hm^-2,显著高于JFN2处理（P<0.05）。综上所述,JZN2处理不仅能够保证小麦产量,且对环境效应最有利,为本区域冬小麦较优的施肥管理模式。     

微塑料输入与秸秆添加对潮土和黄棕壤氮淋溶的影响

为探究微塑料输入与秸秆添加对农田土壤氮淋溶的影响，以潮土和黄棕壤为研究对象，每种土壤各设置8个处理，包括对照（CK）、低量微塑料（PE1）、中量微塑料（PE2）、高量微塑料（PE3）、秸秆（S）、秸秆+低量微塑料（S+PE1）、秸秆+中量微塑料（S+PE2）、秸秆+高量微塑料（S+PE3），研究了添加秸秆与不添加秸秆条件下，不同微塑料输入量对土壤氮淋溶的影响。结果表明，仅添加微塑料条件下，与对照（CK）相比，潮土PE1、PE2、PE3处理总氮（TN）淋溶量均无显著差异，黄棕壤仅PE1处理显著增加了TN淋溶量。在添加秸秆（S）处理中，与对照（CK）相比，潮土添加秸秆后显著降低了硝态氮（NO₃^--N）、铵态氮（NH₄⁺-N）、TN淋溶量，分别降低了31.15%、13.45%、15.26%，黄棕壤添加秸秆后显著增加了TN淋溶量，增加了22.56%。添加秸秆处理相较于不添加秸秆处理，潮土各浓度微塑料输入下NO₃^--N、NH₄⁺-N、TN的累计淋溶量呈降低趋势，而黄棕壤低量微塑料输入降低了TN淋溶量，高量微塑料输入增加了TN淋溶量。偏最小二乘路径模型（PLS-PM）分析表明，在潮土中添加秸秆主要通过影响淋溶液pH和NO₃^--N淋溶量影响氮素淋溶，微塑料添加量对氮淋溶无显著影响；在黄棕壤中添加秸秆主要通过影响淋溶液NO₃^--N、NH₄⁺-N淋溶量影响氮淋溶，微塑料添加量主要通过影响淋溶液NH₄⁺-N淋溶量影响氮淋溶。研究结果可为农田土壤微塑料污染风险的管控及减少土壤氮素的淋失提供依据。     

外源多胺对低氧胁迫下黄瓜幼苗根系活性氧及保护酶活性变化的影响

用亚精胺(Spd)处理了低氧胁迫下的黄瓜幼苗，并对根系中的活性氧及保护酶进行了检测。结果表明，低氧处理后黄瓜幼苗根系的脂质过氧化产物丙二醛(MDA)含量显著升高，活性氧生成速率含量和保护酶活性，都有一个先升后降的过程；Spd处理后，低氧胁迫下的黄瓜幼苗根系中的MDA、活性氧含量显著下降，过氧化物歧化酶(SOD)和过氧化物酶(POD)都保持较高的活性，而过氧化氢酶(CAT)活性较弱。超氧阴离子(O^-₂)生成速率的变化与SOD活性的变化有一定的相关性，H₂O₂的含量变化与过氧化物酶(POD)有一定的相关性。     

仿生膜对轻度加工葡萄自由基和保护酶的影响

以红地球葡萄为试验材料,研究壳聚糖仿生膜对轻度加工葡萄品质和超氧阴离子自由基(O₂^-·)、丙二醛(MDA)含量、电解质渗漏以及超氧化歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等保护酶活性动态变化的影响,探讨轻度加工果实组织衰老和与保护酶的关系,以及仿生膜在果实成熟衰老进程的作用。结果表明：与对照相比,1.5%的壳聚糖仿生膜能抑制SOD、POD、CAT活性下降,减低O₂^-·生成速率,进而抑制MDA的积累,维持细胞膜的稳定性,延缓果实成熟衰老进程。相关性分析表明,O₂^-·生成速率与SOD、CAT呈极显著负相关(r=－0.975^**,－0.546^**),与POD呈显著正相关(r=0.442^*),说明保护酶对抑制O₂^-·产生具有重要作用。1.5%壳聚糖仿生膜可有效抑制保护酶活性降低和自由基的产生,1.2%和1.8%壳聚糖仿生膜没有明显的效果。     

热激减轻柿果冷害与活性氧代谢的关系

为探讨热激处理延缓采后柿子果实冷害的效果，该文研究了柿子果实经48 ℃热空气处理3 h后，在1℃下冷藏期间，热激处理对柿果冷害指数、活性氧清除酶活性、超氧物阴离子自由基(O₂^·-)生成速率和MDA含量的影响。结果表明，热激处理提高了柿果超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)及谷胱甘肽还原酶(GR)活性，降低了超氧物阴离子自由基(O₂^·-)生成速率和MDA含量，并延缓了柿果冷害指数。这表明，热激处理(48℃，3 h)减轻柿果冷害的发生与活性氧清除酶活性的提高，及活性氧积累的降低有关。     

外源一氧化氮对镉胁迫下长春花质膜过氧化、ATPase及矿质营养吸收的影响

重金属污染已成为全球范围的主要问题之一,其中土壤镉（Cd）污染已成为当今社会普遍关注的问题。镉是植物生长发育的非必需元素,极小浓度即可产生较大危害。一氧化氮（NO）是一种氧化还原信号分子和活性氮（RNS）, 参与植物对重金属镉胁迫的应答。长春花（Catharanthus roseus）是我国广泛栽培的兼具园林绿化和抗癌药源等有重要价值的多年生草本花卉植物。为了解镉胁迫下外源NO 对园林地被植物生理响应的调控机制,采用盆栽试验研究了外源NO（硝普钠SNP）对镉胁迫下长春花幼苗生长、 活性氧代谢、 质膜ATPase酶和5'-核苷酸酶活性以及矿质营养元素吸收的影响。结果表明, 25 mg/kg 镉胁迫严重抑制长春花幼苗的生长,显著增加地上部和根系镉的富集量,抑制对大量元素和微量元素的吸收。施加0.45、 0.90、 1.80 mg/kg 的SNP显著降低镉从根系向地上部的转运,缓解因镉胁迫对钾（K）、 钙（Ca）、 镁（Mg） 和 铁（Fe）、 铜（Cu）、 锌（Zn） 吸收产生的抑制效应,降低镉胁迫的毒害作用,促进植物生长。镉胁迫下,丙二醛（MDA）含量和活性氧（O2和H2O2）水平显著升高。施加低浓度 SNP 能够显著缓解细胞质膜过氧化,降低硫代巴比妥酸反应产物（TBARS）堆积,且对抗氧化酶和ATPase酶具有相同作用。添加0.45、 0.90、 1.80 mg/kg 的SNP 可提高镉胁迫下长春花地上部和根系的抗氧化酶［过氧化氢酶（CAT）、 超氧化物歧化酶（SOD）、 过氧化物酶（POD）］活性与抗氧化物（还原型谷胱甘肽GSH）含量,诱导质膜H+-ATPase、 Ca2+-ATPase和 5-AMPase 活性提升到正常水平（对照CK）。添加1.80 mg/kg 的SNP对镉毒害的缓解作用最有效,而添加3.60、 7.20 mg/kg 的SNP的处理则无明显效果。     

Influence of mycorrhizal inoculation and different pruning regimes on fresh root yield of alley and sole cropped cassava (manihot esculenta crantz) in Nigeria

The effect of mycorrhizal fungus inoculation on fresh root yield of cassava (Manihot esculenta crantz) cv TMS 4 (2) 1425 as influenced by two hedgerow tree species and their mixtures, subjected to 2- and 3-month pruning regimes were investigated in alley cropping experiments at three different sites within the same eco-climatic region in Nigeria. Mixture of the prunings of the two hedgerow tree species (Gliricidia sepium and Senna siamea) with mycorrhiza gave higher fresh root yield than the sole hedgerow tree with mycorrhizal inoculation. Gliricidia sepium prunings were found to give higher fresh root yield than the prunings from the Senna siamea. The 2-month prunings of G. sepium recorded higher yield than its 3-month prunings while 2-month prunings of Senna siamea recorded higher yield than its 3-month prunings. However, mycorrhiza inoculation with 2- and 3-month prunings in the two hedgerow species used were found higher than their counterparts without mycorrhizal inoculation in all the three sites. Mycorrhizal inoculation without the hedgerow prunings recorded the lowest fresh root yield but was still higher than the fresh root yield from the sole without mycorrhizal inoculation. Thus, inoculation with mycorrhiza increased alley-cropped cassava fresh root yield over uninoculated plants under both pruning regimes. Generally, this study shows that inoculation of cassava with mycorrhiza alone without mulching with prunings significantly increased cassava fresh root yield.     

Interactions between the arbuscular mycorrhizal fungus Glomus intraradices and the plant growth promoting rhizobacteria Paenibacillus polymyxa and P. macerans in the mycorrhizosphere of Cucumis sativus

Interactions between the arbuscular mycorrhizal (AM) fungus Glomus intraradices and bacteria from the genus Paenibacillus (P. macerans and P. polymyxa) were examined in a greenhouse pot experiment with Cucumis sativus with and without organic matter amendment (wheat bran). P. polymyxa markedly suppressed AM fungus root colonization irrespective of wheat bran amendment, whereas P. macerans only suppressed AM fungus root colonization in combination with wheat bran amendment. Dual inoculation with P. macerans and G. intraradices in combination with wheat bran amendment also caused severe plant growth suppression. Inoculation with G. intraradices was associated with increased levels of dehydrogenase activity and available P in the growth substrate suggesting that mycorrhiza formation accelerated the decomposition of organic matter resulting in mobilization of phosphorus. Inoculation with both Paenibacillus species increased all measured microbial fatty acid biomarkers in the cucumber rhizosphere, except for the AM fungus biomarker 16:1ω5, which was reduced, though not significantly. Similarly, inoculation with G. intraradices increased all measured microbial fatty acid biomarkers in the cucumber rhizosphere, except for the Gram-positive bacteria biomarker 15:0 anteiso, which was overall decreased by G. intraradices inoculation. In combination with wheat bran amendment G. intraradices inoculation caused a 39% reduction in the amount of 15:0 anteiso in the treatment with P. polymyxa, suggesting that G. intraradices suppressed P. polymyxa in this treatment. In conclusion, plant growth promoting species of Paenibacillus may have suppressive effects of AM fungi and plant growth, especially in combination with organic matter amendment. The use of an inert plant growth media in the present study allowed us to study rhizosphere microbial interactions in a relative simple substrate with limited interference from other soil biota. However, the results obtained in the present work mainly show potential interactions and should not be directly extrapolated to a soil situation.     

干旱胁迫下丛枝菌根真菌对玉米生理生化特性的影响

在土壤有效磷含量较高的条件下,研究了接种丛枝菌根真菌（arbuscular mycorrhizal fungus, AMF）对不同水分处理梯度（田间最大持水量的70%、 45%和20%）条件下玉米生长和抗旱性的影响。结果表明,在三种不同水分处理条件下,接种AMF显著提高了玉米植株地上部的生物量,且对玉米地上部、 地下部全磷含量有显著提高作用。水分胁迫显著降低了玉米叶片水势,增加了玉米叶片脯氨酸、 丙二醛、 过氧化物酶和过氧化氢酶含量,而不同水分梯度条件下接种AMF均显著提高了植株叶片水势,降低了脯氨酸含量,提高了叶片保护酶（过氧化物酶和过氧化氢酶）活性从而减少丙二醛的积累,减轻植物叶片膜脂过氧化的伤害。由此说明,接种AMF在土壤有效磷含量较高的条件下能够与玉米根系形成良好的共生关系,提高玉米的抗旱性。     

Sour Orange (Citrus Aurantium L.) Growth is Strongly Mycorrhizal Dependent in Terms of Phosphorus (P) Nutrition Rather than Zinc (Zn)

The partial sterilization of soil eliminates useful microorganisms, resulting in the reduced growth of mycorrhizae-dependent citrus plants, which are often unresponsive to the application of fertilizer. Research was conducted to test the hypothesis that indigenous mycorrhizae (IM) inoculation is as efficient as selected mycorrhizal inoculation under sterile and non-sterile soil conditions. Rhizophagus clarus and indigenous mycorrhiza spores, isolated from citrus orchards, were used as arbuscular mycorrhizae fungi under greenhouse conditions with sterile and non-sterile Çanakçi series (Typic xerofluvent) soils with low phosphorus (P) fertility. Different P (0 and 100 mg kg^?1) and zinc (Zn) (0, 5 and 10 mg kg^?1) concentrations were used at the start of the experiments. The shoot, root dry weight (RDW), root colonization, and P, Zn, iron (Fe), copper (Cu) and manganese (Mn) concentrations of the shoot were determined; mycorrhizae dependency (MD) was also calculated.

The results indicate that R. clarus and indigenous mycorrhiza in sterile and non-sterile soil conditions considerably increased the growth of citrus plants. Owing to existing beneficial indigenous rhizosphere microorganisms, citrus plant growth without inoculation was better in non-sterile soils than in the sterile soils. In non-sterilized soil, the plant growth parameters of R. clarus-inoculated soils were higher than those of indigenous mycorrhiza-inoculated soils. Mycorrhizae infection increased certain citrus plant growth parameters, such as root infection, biomass and nutrient uptake (P, Zn, Fe, Mn and Cu). In sterile soil, the addition of up to 5 mg kg^?1 soil Zn and the inoculation of R. clarus significantly increased plant growth; inoculation with indigenous mycorrhiza produced more dry weight upon the addition of up to 100 mg kg^?1 phosphorus pentoxide (P₂O₅). Under sterile soil conditions, without considering fertilizer addition, MD was found to be higher than that of non-sterile soils. In general, the contribution of the indigenous soil spores is significant. However, indigenous soil mycorrhizae may need to be managed for better efficiency in increasing plant growth and nutrient uptake. The major finding was that the inoculation of citrus seedlings with mycorrhiza is necessary under both sterilized and non-sterilized soil conditions.     

The effects of biological,chemical, and organic fertilizers application on root growth features and grain yield of Sorghum

Abstract

To investigate the effect of some biological and chemical fertilizers on the root physiological and growth indexes and also Sorghum grain yield, this study was carried out in randomized complete block design with three replicates. The treatments of the study included (1) arbuscular mycorrhizal fungus Glomus mosseae?+?vermicompost, (2) mycorrhiza fungus?+?Nitroxin, (3) mycorrhiza fungus+ Rhizobium sp., (4) mycorrhiza fungus?+?NPK chemical fertilizer (40-40-20), (5) mycorrhiza fungus, and (6) control treatment. The highest root colonization rate and specific root length were observed in the co-inoculation with mycorrhiza?+?Nitroxin treatment. The other root growth parameters were observed at the mycorrhiza?+?vermicompost treatment. Also the highest rate of Sorghum physiological growth indexes root such as root area index and net assimilation rate were belonged to the co-inoculation of mycorrhiza?+?Nitroxin treatment. The highest root growth rate and root relative growth rate were obtained in the mycorrhiza?+?vermicompost treatment. So it can be concluded that biological fertilizers can be used as an appropriate alternative for chemical fertilizers in sustainable agriculture system.     

Ca2+和CaM对苹果果实Ca2+-ATPase,SOD和PEA活性的影响

采用45Ca2+ 示踪等方法研究苹果果肉质膜微囊Ca2+ ATPase与Ca2+ 运输之间的关系 ,在Ca2+ 和CaM激活剂和抑制剂存在条件下培养果实圆片 ,探索Ca2+-ATPase ,SOD和PEA活性受Ca2+和 (或 )CaM调控的可能性。结果表明 ,存在于质膜上的Ca2+-ATPase并受载体A23187刺激而活性增加 ,Ca2+-ATPase活性与Ca2+运输依抑制剂EB浓度增加而下降 ,二者变化趋势十分一致 ,从而证实了Ca2+-ATPase推动苹果果肉质膜微囊Ca2+的主动运输。果肉质膜微囊Ca2+-ATPase同时受到Ca2+和CaM调节 ,而SOD和PEA活性仅受Ca2+ 的调节 ,而与CaM无关。     

Effects of mycorrhiza colonization on growth,root exudates,antioxidant activity and photosynthesis trait of cucumber grown in Johnson modified nutrient solution

Mycorrhiza can improve plant growth and increase nutrient uptake. This study was conducted as factorial experiment based on complete random design (CRD) to study effects of mycorrhiza inoculation under limited iron (Fe) condition on antioxidant activity, phenol content and photosynthesis trait of cucumber (Cucumis sativus cv. N3). Treatments were Johnson modified nutrient solution (MNS) with 25% Fe (MNS1) = 0.57 mg/L Fe, 50% (MNS2) = 1.14 mg/L Fe and 100% (MNS3) = 2.3 mg/L Fe and mycorrhiza inoculation (M+) and non-mycorrhiza inoculation (M?) with 3 replications under hydroponic conditions. The results showed that plant growth and shoot phenol content decreased in the MNS1 treatment; whereas phenol content of the root exudates and antioxidant activity significantly increased in this treatment. All photosynthesis attribute increased in the MNS3 treatment. Mycorrhiza inoculation increased plant growth, phenol content, antioxidant activity and photosynthesis trait of cucumber. Also, mycorrhiza inoculation enhanced SPAD value in the MNS2 treatment and photosynthesis rate, transpiration and mesophyll conductance in all the modified nutrient solutions. Moreover, mycorrhiza symbiosis was stimulated by the internal carbon dioxide (CO₂) content of the stomata in the MNS2 and MNS3 treatments. Furthermore, Mycorrhiza inoculation improved phenol content of the shoots and roots in all the nutrient solutions, whereas antioxidant activity was affected by mycorrhiza inoculation only in the MNS2 treatment.     

Interactions between azospirillum and va mycorrhiza and their effects on growth and nutrition of maize and ryegrass

Interactions between the N₂-fixing bacterium Azospirillum brasilense and the mycorrhizal fungus Glomus mosseae were studied in relation to their effects on the growth and nutrition of Zea mays (C₄) and Lolium perenne (C₃) plants. Although roots from plants inoculated with Azospirillum exhibited C₂H₂ reduction activity no significant effect of inoculation on N concentration in the plant shoots was found. With non-mycorrhizal plants, inoculation with Azospirillum resulted in increased dry matter production at the first harvest compared to the effect achieved by supplying N as fertilizer, but this trend was reversed at the last harvest. However, with mycorrhizal maize plants, Azospirillum, which stimulated the development of VA mycorrhiza, was still effective in improving plant growth and nutrient uptake at the last harvest. Azospirillum and N behaved similarly in enhancing the growth and nutrition of mycorrhizal maize. The dual inoculation of maize by Azospirillum and Glomus produced plants of a similar size, N content, and a higher P content, than those supplied with N and P.     

Promotion of mycorrhiza formation and growth of willows by the bacterial strain <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. 23L on fly ash

Re-vegetation of fly ash, the principal by-product of coal fired power stations, is hampered by its unfavourable chemical and physical properties for plant growth. In the present study, we evaluated the use of inoculation with a mycorrhiza-associated bacterial strain (Sphingomonas sp. 23L) to promote mycorrhiza formation and plant growth of three willow clones (Salix spp.) on fly ash from an over-burdened dump in a pot experiment. The high pH_H2O (8.7) and low nitrogen content (N_t = 0.1 g kg⁻¹) in combination with hydrophobicity of the particle surfaces caused low plant growth. Inoculation of the willows with Sphingomonas sp. 23L improved the nitrogen uptake by plants, increased plant growth and stimulated formation of ectomycorrhizae with an autochthonous Geopora sp. strain on all three willow clones. The ectomycorrhiza formed by the Geopora sp. was morphologically and anatomically described. The inoculation significantly increased the shoot growth of two Salix viminalis clones and the root growth of a S. viminalis x caprea hybrid clone. We conclude that inoculation with mycorrhiza promoting bacterial strains might be a suitable approach to support mycorrhiza formation with autochtonous site-adapted ectomycorrhizal fungi in fly ash and thereby to improve re-vegetation of fly ash landfills with willows.