Role Of Arbuscular Mycorrhiza Research Articles

Enhancing tomato plants' tolerance to combined heat and salt stress – The role of arbuscular mycorrhizae and biochar

The Mediterranean basin is highly susceptible to climate change, with soil salinization and the increase in average temperatures being two of the main factors affecting crop productivity in this region. Following our previous studies on describing the detrimental effects of heat and salt stress co-exposure on tomato plants, this study aimed to understand if substrate supplementation with a combination of arbuscular mycorrhizal fungi (AMF) and biochar could mitigate the negative consequences of these stresses. Upon 21 days of exposure, stressed tomato plants grown under supplemented substrates showed increased tolerance to heat (42 °C for 4 h/day), salt (100 mM NaCl), and their combination, presenting increased biomass and flowering rate. The beneficial effects of AMF and biochar were associated with a better ionic balance (i.e. lower sodium accumulation and higher uptake of calcium and magnesium) and increased photosynthetic efficiency. Indeed, these plants presented higher chlorophyll content and improved CO2 assimilation rates. Biochemical data further supported that tomato plants grown with AMF and biochar were capable of efficiently modulating their defence pathways, evidenced by the accumulation of proline, ascorbate, and glutathione, coupled with a lower dependency on energy-costly enzymatic antioxidant players. In summary, the obtained data strongly point towards a beneficial role of combined AMF and biochar as sustainable tools to improve plant growth and development under a climate change scenario, where soil salinization and heat peaks often occur together.

Role of Arbuscular Mycorrhiza (AM) Fungi and Lignin in Biological Control against Vascular Fusarium Wilt Disease

Role of Arbuscular Mycorrhiza (AM) Fungi and Lignin in Biological Control against Vascular Fusarium Wilt Disease

γ-Aminobutyric acid (GABA) and ectoine (ECT) impacts with and without AMF on antioxidants, gas exchange attributes and nutrients of cotton cultivated in salt affected soil

Salinity stress is one of the major hurdles in agriculture which adversely affects crop production. It can cause osmotic imbalance, ion toxicity that disrupts essential nutrient balance, impaired nutrient uptake, stunted growth, increased oxidative stress, altered metabolism, and diminished crop yield and quality. However, foliar application of osmoprotectant is becoming popular to resolve this issue in crops. These osmoprotectants regulate the cellular osmotic balance and protect plants from the detrimental effects of high salt concentrations. Furthermore, the role of arbuscular mycorrhizae (AMF) is also established in this regard. These AMF effectively reduce the salinity negative effects by improving the essential nutrient balance via the promotion of root growth. That’s why keeping in mind the effectiveness of osmoprotectants current study was conducted on cotton. Total of six levels of γ-Aminobutyric acid (GABA = 0 mM, 0. 5 mM, and 1 mM) and ectoine (ECT = 0 mM, 0.25 mM, and 0.5 mM) were applied as treatments in 3 replications. Results showed that 0.5 mM γ-Aminobutyric acid and ectoine performed significantly best for the improvement in cotton growth attributes. It also caused significant enhancement in K and Ca contents of the leaf, stem, bur, and seeds compared to the control. Furthermore, 0.5 mM γ-Aminobutyric acid and ectoine also caused a significant decline in Cl and Na contents of leaf, stem, bur, and seeds of cotton compared to control under salinity stress. A significant enhancement in chlorophyll contents, gas exchange attributes, and decline in electrolyte leakage validated the effectiveness of 0.5 mM γ-Aminobutyric acid and ectoine over control. In conclusion, 0.5 mM γ-Aminobutyric acid and ectoine have the potential to mitigate the salinity stress in cotton.

THE ROLES OF ARBUSCULAR MYCORRHIZAE IN SUPPORTING THE MANGROVE GROWTH

The current study aims to determinate the potential of Arbuscular mycorrhizae in supporting the mangrove growth, the role of Arbuscular mycorrhizae on the improvement of mangrove growth in terms of its colonization level with the mangrove roots, the mangrove ability of Arbuscular mycorrhizae in the way of supporting the rehabilitation of mangroves, and giving the recommendation to the local government related to the potential of mycorrhizal fungi in rehabilitating the degraded magrove areas living in the coastal areas of Kwandang, North Gorontalo regency.
 Moreover, this study used a descriptive qualitative analysis method using ex-post-facto approach. To collect the data, it used a pruposive sampling on rhizosfer and mangrove roots in order to observe the spore density, the diversity and the mycorrhizal colonization.
 The results of this study show that the ability of Arbuscular mycorrhizae in supporting the mangrove growth is categorized in the high level. It can be seen from the spora density. On average in research location, the number of the spores that were successfully isolated is 42 spores/ 100 grams of soil. Arbuscular mycorrhizae has a role in the way of increasing the mangrove growth. This can be seen from the high percentage of colonization with mangrove roots whereas 57,87%.

Role of arbuscular mycorrhizas in citrus (Citrus spp.) crop production—a review

Role of arbuscular mycorrhizas in citrus (<i>Citrus</i> spp.) crop production—a review

The Role of Mycorrhiza in Transformation of Nitrogen Compounds in Soil and Nitrogen Nutrition of Plants: A Review

The role of mycorrhizal symbiosis as a control of the biogeochemical cycle of nitrogen in soils and in the nitrogen nutrition of plants is considered. The contribution of ericoid mycorrhiza (ErM) and ectomycorrhiza (EcM) to nitrogen (N) supply of host plants is well known, whereas the role of arbuscular mycorrhiza (ArM) is insufficiently understood. Exoenzymes released into the soil from the ErM and EcM mycelium favor the hydrolysis of high-molecular-weight N-containing organic compounds of plant litter and soils to $${\text{NH}}_{4}^{ + }$$ or amino acids that are then transported toward plant roots and are absorbed by them. ArM-producing fungi have a limited capacity to release hydrolytic enzymes capable to decompose high-molecular-weight organic compounds into the soil (or do not have it at all). Therefore, they are specialized on the absorption of inorganic forms of N and amino acids appearing in the soil in the course of decomposition of high-molecular-weight N-containing compounds by saprotrophic microorganisms. The activity of hydrolytic exoenzymes and the role of mycorrhiza in the nitrogen nutrition of plants become more significant under conditions of the low supply with mineral N compounds and decrease upon the rise in availability of mineral N compounds. At the same time, mycorrhizal fungi and host plants may compete for the limited resource. The isotopic composition of N in plants (δ15N) and the fractionation of 15N isotope between the mycorrhizal fungi and host plants are considered indicative of the participation of mycorrhiza in the nitrogen nutrition of plants.

Role of arbuscular mycorrhiza in alleviating the effect of cold on the photosynthesis of cucumber seedlings

Arbuscular mycorrhiza (AM) is known to enhance the rate of photosynthesis in plants, but there is little information on whether this effect is maintained at low temperature when the development of AM fungi is restrained. We therefore investigated the influence of AM on gas exchange, PSII fluorescence, and some photosynthesis-related biochemical parameters in cucumber seedlings under cold stress. Cold stress decreased, as expected, the chlorophyll content, net photosynthetic rate, and parameters related to photochemical quenching, while increasing nonphotochemical quenching and sugar contents in leaves. In contrast, AM had opposite effects on most of the determined parameters; it improved the efficiency of photosynthesis in the cucumber seedlings both at cold stress and at control ambient temperature. In addition, we recorded significant alleviation of the cold stress effect on sugar contents in leaves, which indicated that higher carbon-sink strength was an important factor maintaining higher efficiency of photosynthesis in mycorrhizal cucumber seedlings under cold stress.

The role of arbuscular mycorrhiza in mercury and mineral nutrient uptake in maize

This work aimed to study the role of arbuscular mycorrhizal fungi (AMF) in Hg and major mineral nutrient uptake and tissue localization of these elements in the roots of maize plants. Maize plants were grown in pots filled with non- and Hg-contaminated substrate (50 μg Hg g−1 as HgCl2) and inoculated with two types of AMF inocula: a) Glomus sp. originating from Hg-polluted soil of a former Hg smelting site in Idrija, Slovenia, and b) commercial AM inoculum Symbivit. Controls were inoculated by corresponding bacterial extracts only. Tissue localization of Hg and major mineral nutrients was performed by laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) on cryofixed and freeze-dried root cross-sections. AMF colonization increased plant biomass in non-contaminated substrate, while this effect was not seen in Hg-contaminated substrate. Hg increased total plant biomass more than AMF inoculation, possibly through hormetic effects. AMF increased Hg uptake into the roots, as well as Hg transfer to the shoots. AMF affected plant mineral nutrient uptake, depending on the type of AMF inoculum and the presence of Hg. In the roots, Hg was mainly localized in rhizodermis and endodermis, followed by the cortex and the central cylinder. Higher Hg concentrations were detected in the central cylinder of AM plants than in that of the controls, pointing to a higher Hg mobility and potential bioavailability in AMF inoculated plants.

The impact of domestication and crop improvement on arbuscular mycorrhizal symbiosis in cereals: insights from genetics and genomics.

Contents Summary 1135 I. Introduction 1135 II. Recruitment of plant metabolites and hormones as signals in AM symbiosis 1136 III. Phytohormones are regulators of AM symbiosis and targets of plant breeding 1137 IV. Variation in host response to AM symbiosis 1137 V. Outlook 1137 Acknowledgements 1139 References 1139 SUMMARY: Cereals (rice, maize, wheat, sorghum and the millets) provide over 50% of the world's caloric intake, a value that rises to >80% in developing countries. Since domestication, cereals have been under artificial selection, largely directed towards higher yield. Throughout this process, cereals have maintained their capacity to interact with arbuscular mycorrhizal (AM) fungi, beneficial symbionts that associate with the roots of most terrestrial plants. It has been hypothesized that the shift from the wild to cultivation, and above all the last c. 50years of intensive breeding for high-input farming systems, has reduced the capacity of the major cereal crops to gain full benefit from AM interactions. Recent studies have shed further light on the molecular basis of establishment and functioning of AM symbiosis in cereals, providing insight into where the breeding process might have had an impact. Classic phytohormones, targets of artificial selection during the generation of Green Revolution semi-dwarf varieties, have emerged as important regulators of AM symbiosis. Although there is still much to be learnt about the mechanistic basis of variation in symbiotic outcome, these advances are providing an insight into the role of arbuscular mycorrhiza in agronomic systems.

Arbuscular mycorrhizal fungi increase the proportion of cellulose and hemicellulose in the root stele of vetiver grass

Arabidopsis thaliana is the model plant that is mainly used in studying cellulose and hemicellulose (CH) biosynthesis. Unfortunately, A. thaliana does not associate with mycorrhiza and as a result there are only rare reports on the role of arbuscular mycorrhiza (AM) fungi on CH biosynthesis. This study aims to investigate the effects of AM fungi on changing the CH content in mycorrhizal plant. Three AM fungi, Glomus aggregatum, Rhizophagus intraradices and Funneliformis mosseae, were inoculated to vetiver grass (Chrysopogon zizanioides) and grown for 12 months. Roots were harvested, and the proportions of CH, lignin, lipids and hydrosoluble content were analysed. The corresponding root tensile strength (positively correlated with the proportion of CH) was measured to counter check the CH content. Plants inoculated with AM showed a higher proportion of CH (P < 0.05) compared with uninoculated ones. This increase was coupled to a 40–60% enhancement in tensile strength. Potential mechanisms for this phenomenon are discussed. This is the first study showing that the proportion of CH and tensile strength of plant root could be significantly affected by AM symbiosis. It is thus desirable that future research on CH biosynthesis uses mycorrhizal-associating plants, such as medic (Medicago truncatula) and rice (Oryza sativa).

The role of arbuscular mycorrhiza in zinc uptake by lettuce grown at two phosphorus levels in the substrate

Arbuscular mycorrhizal fungi (AMF) play an important role in Zn uptake by plants and can partially mitigate the effects of its deficit. On the other hand, they are involved in reducing the accumulation of Zn and its toxicity to plants when it is present in excessive concentrations in the soil. The aim of the study was to investigate the effect of two AMF, i.e., Funneliformis mosseae and Rhizophagus intraradices on Zn uptake by lettuce plants grown at two P levels and elevated concentrations of Zn in a peat substrate. The experiment demonstrated the effectiveness of mycorrhization of lettuce grown in the peat substrate; however, the arbuscular mycorrhiza did not reduce the uptake of Zn by lettuce. The AMF used in the experiment differentially affected the Zn content in lettuce. Compared to uninoculatedplants, R. intraradices increased the Zn content in lettuce, whereas F. mosseae did not affect the Zn content.

The role of arbuscular mycorrhizas in reducing soil nutrient loss.

Substantial amounts of nutrients are lost from soils via leaching and as gaseous emissions. These losses can be environmentally damaging and expensive in terms of lost agricultural production. Plants have evolved many traits to optimize nutrient acquisition, including the formation of arbuscular mycorrhizas (AM), associations of plant roots with fungi that acquire soil nutrients. There is emerging evidence that AM have the ability to reduce nutrient loss from soils by enlarging the nutrient interception zone and preventing nutrient loss after rain-induced leaching events. Until recently, this important ecosystem service of AM had been largely overlooked. Here we review the role of AM in reducing nutrient loss and conclude that this role cannot be ignored if we are to increase global food production in an environmentally sustainable manner.

International Congress on Mycorrhizae: mycorrhizal symbiosis a key factor for improving plant productivity and ecosystems restoration.

The Mycorrhizae and Mediterranean Ecosystems Group (MYCOMED), the African Network on Mycorrhiza (AFRINOM) and the French Mycorrhizologist Network (RAMYF) co-organized an International Congress on BMycorrhizal Symbiosis a Key Factor for Improving Plant Productivity and Ecosystems Restoration^ in Marrakech, Morocco, October 15–17, 2014. Three hundred participants from 45 different countries attended the congress, which included 65 oral presentations and 100 posters. Abstracts of all talks and posters can be found at the website (http://icmycorrhizae2014.uca.ma) of Cadi Ayyad University. The congress was an international forum for exchange of knowledge and expertise between scientists developing fundamental and applied mycorrhizal research as well as companies commercializing mycorrhizal inoculum. The objectives were to update scientific and technical knowledge on mycorrhizal fungi as providers of key ecological services, to valorize the mycorrhizal symbiosis in practices in the socioeconomic environment of Mediterranean and tropical areas and to share the experiences of scientists with young researchers, policy makers and end-users. The contents addressed included three topics: (i) biology, ecology and diversity of mycorrhizal fungi in tropical and Mediterranean environments; (ii) mycorrhizal symbiosis and plant tolerance to biotic and abiotic stresses and (iii) valorization and transfer of mycorrhizal biotechnologies in agro-ecological engineering strategies and the socio-economic environment of tropical and Mediterranean areas. In the opening conference on the role of arbuscular mycorrhiza for plant health, Prof. Paola Bonfante (Italy) provided an overview on the cellular and molecular mechanisms which allow plants to take up essential minerals in model legume plants, and revealed how mycorrhiza may have a systemic impact on the fruit transcriptomics and nutrient content in agricultural important crops such as tomato. Dr. Marc Buee (France) introduced topic (i) by raising the fundamental question of how to connect metagenomics and mycorrhizal fungal ecology. Through various examples, spanning from local to large-scale studies using biogeographic approaches, he presented the advantages and risks of highthroughput sequencing to investigate ectomycorrhizal fungal ecology, with unprecedented scales of sampling, and illustrated how fungal genome resources feed metagenomics to increase knowledge on the ecology of mycorrhizal fungal communities and assemblages. In introducing topic (ii), Prof. Guillaume Becard (France) talked about plant mechanisms that discriminate beneficial and pathogenic microorganisms via microbial signals. These molecular signals are involved in the processes of nodulation, mycorrhization, root development and basal plant immunity. They could have a huge potential for sustainable agriculture because of their implication in enhancing plant nutrition, growth and defense against pathogens and pests. Dr. Silvio Gianinazzi (France) introduced topic (iii) by presenting the domestication of beneficial soil microorganisms as an innovative technology for agriculture. He suggested that Mohamed Hafidi, Ahmed Qaddoury, Robin Duponnois, Daniel Wipf, Mohamed Hijri and Amadou Bâ contributed equally to this work.

Chromium toxicity and tolerance in plants

Chromium (Cr) is the second most common metal contaminant in ground water, soil, and sediments due to its wide industrial application, hence posing a serious environmental concern. Among various valence states, Cr(III) and Cr(VI) are the most stable forms. Cr(VI) is the most persistent in the soil and is highly toxic for biota. Since Cr is a non-essential element for plants, there is no uptake mechanism; Cr is taken up along essential elements such as sulfate through sulfate transporters. Cr accumulation in plants causes high toxicity in terms of reduction in growth and biomass accumulation, and Cr induces structural alterations. Cr interferes with photosynthetic and respiration processes, and water and minerals uptake mechanism. Various enzymatic activities related to starch and nitrogen metabolism are decreased by Cr toxicity either by direct interference with the enzymes or through the production of reactive oxygen species. Cr causes oxidative damage by destruction of membrane lipids and DNA damage. Cr may even cause the death of plant species. Few plant species are able to accumulate high amount of Cr without being damaged. Such Cr-tolerant, hyperaccumulator plants are exploited for their bioremediation property. The present review discusses Cr availability in the environment, Cr transfer to biota, toxicity issues, effect on germination and plant growth, morphological and ultrastructural aberrations, biochemical and physiological alterations, effect on metabolic processes, Cr-induced alterations at the molecular level, Cr hyperaccumulation and Cr detoxification mechanism, and the role of arbuscular mycorrhizae in Cr toxicity, in plants.

The role of arbuscular mycorrhizas in decreasing aluminium phytotoxicity in acidic soils: a review

Soil acidity is an impediment to agricultural production on a significant portion of arable land worldwide. Low productivity of these soils is mainly due to nutrient limitation and the presence of high levels of aluminium (Al), which causes deleterious effects on plant physiology and growth. In response to acidic soil stress, plants have evolved various mechanisms to tolerate high concentrations of Al in the soil solution. These strategies for Al detoxification include mechanisms that reduce the activity of Al3+ and its toxicity, either externally through exudation of Al-chelating compounds such as organic acids into the rhizosphere or internally through the accumulation of Al-organic acid complexes sequestered within plant cells. Additionally, root colonization by symbiotic arbuscular mycorrhizal (AM) fungi increases plant resistance to acidity and phytotoxic levels of Al in the soil environment. In this review, the role of the AM symbiosis in increasing the Al resistance of plants in natural and agricultural ecosystems under phytotoxic conditions of Al is discussed. Mechanisms of Al resistance induced by AM fungi in host plants and variation in resistance among AM fungi that contribute to detoxifying Al in the rhizosphere environment are considered with respect to altering Al bioavailability.

Role of Arbuscular Mycorrhizae (AM) Fungi and Multi Bioinoculants in Cotton Plant Growth

Aim: The present study reflects the effect of Arbuscular Mycorrhizae (AM) fungi and other bioinoculants on the growth of cotton seedlings. Study Design: Screening of efficient biofertilizers from undisturbed forest soils to improve the crop yield of cotton in barren lands of Mahabubnagar District. Place and Duration of Study: Department of Microbiology, Palamuru University, Mahabubnagar, Andhra Pradesh, India, between May 2011 and February 2012. Methodology: Mahyco hybrid variety, the most widely cultivated variety in Mahabubnagar District, Andhra Pradesh, India was selected among the sixteen varieties of cotton seeds for this study. Soil samples were analyzed for physicochemical characteristics. Seven different isolates of AM fungi were maintained as pure cultures in laboratory, which were isolated from different Agroforestry tree rhizosphere soils. Among these pure cultures, R1R2 has shown maximum colonization with Mahyco variety and this isolate was identified as Glomus mosseae. Mahyco hybrid variety was also tested with three different bioinoculants (Rhizobium sp., Azospirillum sp., Bacillus sp.) along with the combination of AM pure culture of R1-R2. These three potential bioinoculants were identified based on 16S rRNA gene sequence. Preliminarily Mahyco hybrid variety was investigated with individual pure cultures of AM fungi and with other bioinoculants. R1-R2 was taken in single, dual, triple and multi combinations with other three bioinoculants. Research Article British Microbiology Research Journal, 2(3): 123-130, 2012 124 Results: In single combination M+R1-R2 showed the best growth by M+Rhizobium, followed by M+Bacillus and in dual combination M+R1-R2+Rhizobium and in triple combination M+R1-R2+Rhizobium+Azospirillum and in multicombination i.e. M+R1R2+Rhizobium+Azospirillum+Bacillus showed the best growth among all the combinations. Conclusion: The multicombination mediates increased the cotton growth characteristics. The effect of multicombination was not significantly different in treatment affected by various varieties. Inoculation of multicombination along with AM pure culture resulted significant increase in shoot and root length of cotton plant. So multicombination was proved to be superior.

Roles of Arbuscular Mycorrhizas in Plant Nutrition and Growth: New Paradigms from Cellular to Ecosystem Scales

Root systems of most land plants form arbuscular mycorrhizal (AM) symbioses in the field, and these contribute to nutrient uptake. AM roots have two pathways for nutrient absorption, directly through the root epidermis and root hairs and via AM fungal hyphae into root cortical cells, where arbuscules or hyphal coils provide symbiotic interfaces. New physiological and molecular evidence shows that for phosphorus the mycorrhizal pathway (MP) is operational regardless of plant growth responses (positive or negative). Amounts delivered cannot be determined from plant nutrient contents because when responses are negative the contribution of the direct pathway (DP) is reduced. Nitrogen (N) is also delivered to roots via an MP, but the contribution to total N requirement and the costs to the plant are not clear. The functional interplay between activities of the DP and MP has important implications for consideration of AM symbioses in ecological, agronomic, and evolutionary contexts.

Roles of arbuscular mycorrhizas in plant phosphorus nutrition: interactions between pathways of phosphorus uptake in arbuscular mycorrhizal roots have important implications for understanding and manipulating plant phosphorus acquisition.

Arbuscular mycorrhizal (AM) symbiosis is the most common plant strategy that increases phosphorus (P) acquisition, involving approximately 80% of terrestrial plants. The AM fungal symbionts provide a very effective pathway (the AM pathway) for uptake, scavenging P from large soil volumes and overcoming depletion in the rhizosphere that occurs when direct (epidermal) root uptake is faster than replacement from the bulk soil. Recent physiological and molecular research has shown that the AM pathway makes very large contributions to total plant P even in plants that show no growth increases when AM, compared with non-mycorrhizal (NM) counterparts. The AM contribution remains unless radioactive tracers are used to track delivery via the AM pathway. Importantly, this finding demonstrates that the direct pathway delivers less P to AM plants than to NM counterparts and implies fungus-to-plant signaling. The mechanisms by which direct uptake is reduced are unknown, but the hidden contribution of AM uptake means that AM fungi cannot be regarded as parasites, because there is mutualistic exchange of P for organic C regardless of plant growth responses. Furthermore, the dominance of the AM pathway helps to explain the persistence of AM symbiosis over evolutionary time, even in plants that apparently show no benefits.

Arsenic toxicity in crop plants: physiological effects and tolerance mechanisms

Heavy metals are toxic substances released into the environment, contributing to a variety of toxic effects on living organisms in food chain by accumulation and biomagnifications. Certain pollutants such as arsenic (As) remain in the environment for an extensive period. They eventually accumulate to levels that could harm physiochemical properties of soils and lead to loss of soil fertility and crop yield. Arsenic, when not detoxified, may trigger a sequence of reactions leading to growth inhibition, disruption of photosynthetic and respiratory systems, and stimulation of secondary metabolism. Plants respond to As toxicity by a variety of mechanisms including hyperaccumulation, antioxidant defense system, and phytochelation. Arbuscular mycorrhizae symbiosis occurs in almost all habitats and climates, including disturbed soils. There is growing evidence that arbuscular mycorrhizae fungi may alleviate metal/metalloid toxicity to host plant. Here, we review (1) arsenic speciation in the environment and how As is taken up by the roots and metabolised within plants, and (2) the role of arbuscular mycorrhizae in alleviating arsenic toxicity in crop plants.

Alleviation of salt-induced ionic, osmotic and oxidative stresses in Cajanus cajan nodules by AM inoculation

Legume-Rhizobium symbiotic nitrogen (N2) fixation plays a critical role in sustainable nitrogen management in agriculture. The nitrogen fixed by the root nodules not only affects the nitrogen cycle of nature, but is also of great economic importance. A number of physiological and biochemical processes in the nodules are affected by salt stress. The objective of this study was to evaluate the role of arbuscular mycorrhiza (AM) in moderating toxic effects of salt stress on nodular metabolism in Cajanus cajan (L.) Millspaugh (pigeonpea) cv. Manak. Exposure of plants to salinity stress (4, 6 and 8 dSm−1) caused ionic imbalance, which resulted in increased Na+ and reduced K+ and Ca2+ contents in the nodules. Salinity induced increased synthesis and accumulation of proline and glycine betaine. Salt stress significantly increased the antioxidant enzyme activities in the nodules of all plants. Nodular growth suffered remarkably and a marked decline in nodule biomass was observed under salt stress. Leghemoglobin content and acetylene reduction activity (ARA) also declined under saline conditions. AM could significantly improve nodule dry mass, leghemoglobin content and nitrogenase activity, and phosphorus content under salt stress. Activities of antioxidant enzymes increased markedly in nodules of mycorrhizal-stressed plants. This study suggested a correlation between improved functional efficiency of nodules and higher osmolyte accumulation and enhanced antioxidant enzyme activities of AM plants under stressed conditions relative to the nodules of uninoculated plants.