Mycorrhizal infection of wild oats: maternal effects on offspring growth and reproduction

Summary The objective of this study was to determine whether infection of Avena fatua L. plants by the mycorrhizal fungus Glomus intraradices Schenck & Smith could influence the vigor of the offspring generation. Two experiments demonstrated that mycorrhizal infection of the maternal generation had slight but persistent positive effects on offspring leaf expansion in the early stages of growth. In two other experiments, mycorrhizal infection of mother plants had several long lasting effects on their offspring. Offspring produced by mycorrhizal mother plants had greater leaf areas, shoot and root nutrient contents and root:shoot ratios compared to those produced by non-mycorrhizal mother plants. Moreover, mycorrhizal infection of mother plants significantly reduced the weight of individual seeds produced by offspring plants while it increased the P concentrations of the seeds and the number of seeds per spikelet produced by offspring plants. The effects of mycorrhizal infections of maternal plants on the vigor and performance of offspring plants were associated with higher seed phosphorus contents but generally lighter seeds. The results suggest that mycorrhizal infection may influence plant fitness by increasing offspring vigor and offspring reproductive success in addition to previously reported increases in maternal fecundity.     

Tolerance ofFestuca rubra L. to zinc in relation to mycorrhizal infection

Summary Plant yield of mycorrhizal and non-mycorrhizalFestuca rubra L. was linearly decreased with increasing zinc concentrations in nutrient solution. In all cases, non-mycorrhizal plant growth was significantly greater than that of mycorrhizal plants. Zinc and phosphorus concentrations of root and shoot of mycorrhizal plants were greater in all zinc treatments while mycorrhizal plants showed equal or lower tolerance indices to zinc than non-mycorrhizal plants. Yield depressions of mycorrhizal plants may be the result of enhanced zinc and phosphorus concentrations combined with the cost for growth and maintenance of the mycorrhizal fungi.     

Impact of Crown Rust (Puccinia coronata f. sp. avenae) on Competitive Interactions between Wild Oats (Avena fatua) and Stipa (Nassella pulchra)

Crown rust of oats (Puccinia coronata f. sp. avenae) was investigated as a biocontrol agent for wild oats (Avena fatua) on San Clemente Island, California. Successful restoration of the native habitats of this island will involve the reduction of wild oats and revegetation with native grasses such as stipa (Nassella pulchra). Determination of the outcome of interference between wild oats and stipa is important in the prediction of the success of the biocontrol agent. An addition series design was used to investigate these interactions, with densities of each species ranging from 0 to 2000 seeds per m². Eight replicates were established, four of which were randomly chosen and infected with the pathogen. After 75 days, plant height, dry weight, and seed production were measured. The data were fit to a hyperbola surface model by use of a nonlinear regression procedure. Results indicate that wild oat is the superior competitor at the seedling stage; however, early rust infection greatly reduces fitness of wild oats, causing an increased fitness for stipa. Simulations with a plant community model constructed from the results of the greenhouse experiment and information in the literature indicated that an equilibrium may be established between wild oat and stipa if high initial seeding rates of stipa are used in revegetation.     

Effect of vesicular arbuscular mycorrhiza and soluble phosphate onAbelmoscus esculentus (L.) Moench

Summary Effect of VA mycorrhiza and soluble phosphorus onAbelmoscus esculentus (L.) Moench was studied in a phosphorus deficient sandy loam soil with pH 5.5. The mycorrhizal infection and spore production were reduced by an increase of added soluble phosphorus. Root, shoot and total plant dry weight were significantly greater in mycorrhizal plants than in non-mycorrhizal controls, at all levels of added soluble P. Mycorrhizal dependency was found to decrease with increase in added soluble P. Depression of growth, as compared with growth at 100% was noticed in mycorrhizal plants when 200% of the recommended P was added.     

Regulation of reproduction in wild and cultivatedLycopersicon esculentum Mill. by vesicular-arbuscular mycorrhizal infection

Summary We examined how mycorrhizal infection byGlomus etunicatum Becker and Gerd. affected flowering phenology and components of reproduction in eight wild accessions and two cultivars ofLycopersicon esculentum Mill. We did this by performing a detailed demographic study of flower, fruit and seed production. Mycorrhizal infection had variable effects on the ten accessions. Infection significantly decreased the time taken to initiate flowering in some accessions. In addition, infection increased flowering duration in some accessions. In many accessions, infection significantly increased seed production, primarily by increasing the number of inflorescences and infructescences. In some accessions, mycorrhizal infection also increased the proportion of flowers that produced mature fruits or the number of seeds per fruit. Among accessions, shoot phosphorus content was correlated with seed productivity for both mycorrhizal and non-mycorrhizal plants. However, non-mycorrhizal plants produced more seed biomass per mg of shoot phosphorus than mycorrhizal plants.     

Growth response and phosphorus uptake of rye with long and short root hairs: Interactions with mycorrhizal infection

Plant growth and phosphorus (P) uptake of two selections of rye (Secale cereale L.) differing in length of root hairs, in response to mycorrhizal infection were investigated. Rye plants with short root hairs (SRH) had a greater length of root infected by Glomus intraradices (up to 32 m pot^–1) than those with long root hairs (LRH) (up to 10 m pot^–1). Application of P decreased the percentage of root length infected in both selections. In low-P soil, mycorrhizal infection increased shoot and root P concentration, especially in LRH plants. Generally, LRH had higher shoot dry weight than SRH plants. P uptake was increased both by LRH and by mycorrhizal infection. Differences in specific P uptake and P utilization efficiency between SRH and LRH plants were observed in non-mycorrhizal plants. With low P supply, P utilization efficiency (dry matter yield per unit of P taken up) of LRH plants increased with time. However, mycorrhizal infection reduced P utilization efficiency, particularly of SRH plants. SRH plants, which were agronomically less efficient (i.e. low dry matter yield at low P supply) were more responsive to either mycorrhizal infection or P addition than the LRH plants. No interaction was observed between mycorrhizal infection and root hair length.     

Contribution of an arbuscular mycorrhizal fungus to the uptake of cadmium and nickel in bean and maize plants

Two experiments were carried out in pots with three compartments, a central one for root and hyphal growth and two outer ones which were accessible only for hyphae of the arbuscular mycorrhizal fungus, Glomus mosseae ([Nicol. and Gerd.] Gerdemann and Trappe). In the first experiment, mycorrhizal and nonmycorrhizal bean (Phaseolus vulgaris L.) plants were grown in two soils with high geogenic cadmium (Cd) or nickel (Ni) contents. In the second experiment, mycorrhizal and nonmycorrhizal maize (Zea mays L.) or bean plants were grown in a non-contaminated soil in the central compartment, and either the Cd- or Ni-rich soil in the outer compartments. In additional pots, mycorrhizal plants were grown without hyphal access to the outer compartments. Root and shoot dry weight was not influenced by mycorrhizal inoculation, but plant uptake of metals was significantly different between mycorrhizal and nonmycorrhizal plants. In the first experiment, the contribution of mycorrhizal fungi to plant uptake accounted for up to 37% of the total Cd uptake by bean plants, for up to 33% of the total copper (Cu) uptake and up to 44% of the total zinc (Zn) uptake. In contrast, Ni uptake in shoots and roots was not increased by mycorrhizal inoculation. In the second experiment, up to 24% of the total Cd uptake and also up to 24% of the total Cu uptake by bean could be attributed to mycorrhizal colonisation and delivery by hyphae from the outer compartments. In maize, the mycorrhizal colonisation and delivery by hyphae accounted for up to 41% of the total Cd uptake and 19% of the total Cu uptake. Again, mycorrhizal colonisation did not contribute to Ni uptake by bean or maize. The results demonstrate that the arbuscular mycorrhizal fungus contributed substantially not only to Cu and Zn uptake, but also to uptake of Cd (but not Ni) by plants from soils rich in these metal cations. Deceased 21 September 1996 Deceased 21 September 1996     

Root apical meristems ofAllium porrum L. as affected by arbuscular mycorrhizae and phosphorus

Summary Arbuscular mycorrhizal (AM) fungi significantly improve plant growth in soils with low phosphorus availability and cause many changes in root morphology, similar to those produced by increased P nutrition, mainly depending on root apex size and activity. The aim of this work was to discriminate between the morphogenetic role of AM fungi and P in leek (Allium porrum L.) by feeding mycorrhizal and nonmycorrhizal plants with two nutrient solutions containing 3.2 or 96 M P and examining specific parameters related to adventitious root apices (apex size, mitotic cycle, and RNA synthesis). The results showed that AM fungi blocked meristem activity as indicated by the higher percentages of inactive apices and metaphases in the apical meristem of mycorrhizal plants, whereas the high P supply lengthened the mitotic cycle without blocking the apices, resulting in steady, slow root growth. The possible involvement of abscisic acid in the regulation of root apex activity is discussed.Abbreviations ABA abscisic acid - AM arbuscular mycorrhizae - CI and CII nonmycorrhizal control plants grown with low or high phosphorus concentration - MI and MII mycorrhizal plants grown with low or high phosphorus concentration - PGR plant growth regulator     

A COMPARATIVE STUDY OF THE GROWTH OF WILD OATS (AVENA FATUA L. AND A. LUDOVICIANA DUR.) AND OF CULTIVATED CEREALS WITH VARIED NITROGEN SUPPLY

Growth analysis of wild oats ( Avena fatua and A. ludoviciana ) grown in pots with different levels of nitrogen supply showed many similarities to spring barley, winter oats and winter wheat.
Small differences that could affect competition between wild oats and cereals occurred mainly in the seedlings. Wild oat seedlings were smaller than the corresponding cultivated cereals in total dry weight, total nitrogen content, leaf area and number of shoots. However, very young wild oat plants had higher net assimilation rates than the cultivated cereals and soon caught up and passed them. The difference in net assimilation rate did not persist, and in the later stages of growth differences in dry-matter production depended mainly on differences in leaf area. Another important difference between wild oats and cultivated cereals was that 98–100% of the wild oat seeds and none of the crop seeds were dormant 2 months after harvest.
Ear emergence in wild oats spread over a longer period, the range of ear heights was greater and the tallest ears were taller than in the corresponding cultivated cereals. Assimilation in the ear appeared to account for less of the total dry matter of the plants of wild and cultivated oats than of wheat. The wild oats produced more seeds per plant than the cultivated cereals, but the 1000-grain weight, and hence the total dry weight of seeds, was lower in the weeds than in the crop.
Addition of nitrogen to the soil affected the growth of the wild oats in the same ways as the cultivated cereals; they took up the same amount of nitrogen per plant as winter oats and winter wheat but more than spring barley.
It is concluded that wild oats are most susceptible in the seedling stage to competition from the crop and that nitrogenous fertilizer applied to an infested field is unlikely to alter the balance between the yields of crop and of wild oats.     

Functional aspects of root architecture and mycorrhizal inoculation with respect to nutrient uptake capacity

The aim of this research was to investigate the effect of arbuscular mycorrhizal (AM) colonisation on root morphology and nitrogen uptake capacity of carob ( Ceratonia siliqua L.) under high and low nutrient conditions. The experimental design was a factorial arrangement of presence/absence of mycorrhizal fungus inoculation ( Glomus intraradices) and high/low nutrient status. Percent AM colonisation, nitrate and ammonium uptake capacity, and nitrogen and phosphorus contents were determined in 3-month-old seedlings. Grayscale and colour images were used to study root morphology and topology, and to assess the relation between root pigmentation and physiological activities. AM colonisation lead to a higher allocation of biomass to white and yellow parts of the root. Inorganic nitrogen uptake capacity per unit root length and nitrogen content were greatest in AM colonised plants grown under low nutrient conditions. A better match was found between plant nitrogen content and biomass accumulation, than between plant phosphorus content and biomass accumulation. It is suggested that the increase in nutrient uptake capacity of AM colonised roots is dependent both on changes in root morphology and physiological uptake potential. This study contributes to an understanding of the role of AM fungi and root morphology in plant nutrient uptake and shows that AM colonisation improves the nitrogen nutrition of plants, mainly when growing at low levels of nutrients.     

Arbuscular mycorrhizal fungi from three genera induce two-phase plant growth responses on a high P-fixing soil

Plant growth enhancing effects of arbuscular mycorrhizal (AM) fungi are suitably quantified by comparisons of mycorrhizal and non-mycorrhizal plant growth responses to added phosphorus (P). The ratio between the amounts of added P required for the same yield of mycorrhizal and non-mycorrhizal plants is termed the relative effectiveness of the mycorrhiza. Variation in this relative effectiveness was examined for subterranean clover grown on a high P-fixing soil. Plants were either left non-mycorrhizal or inoculated with one of three AM fungal species with well-characterised differences in external hyphal spread. With no P added, plants from all treatments produced <10% of their maximum growth achieved at non-limiting P supply. The growth response of non-mycorrhizal plants was markedly sigmoid. Mycorrhizal growth responses were not sigmoid but their shape was two-phased. The first phase was an asymptotic approach to 25–30% of maximum growth, followed by a second asymptotic rise to maximum growth. Growth effects of Glomus invermaium and Acaulospora laevis were quite similar. Plants in these treatments produced up to four times greater shoot dry biomass than non-mycorrhizal plants. Scutellospora calospora was less effective. The relative effectiveness of AM fungi varied with the level of P application. This is expected to apply to all soils on which a sigmoid response is obtained for growth of non-mycorrhizal plants. In a simple approximation the relative effectiveness was calculated to range from 1.46 to 15.57. Shoot P contents were increased by up to 25 times by A. laevis, significantly more than by the other two fungi. The further mycelial spread of this fungus is thought to have contributed to its relatively greater effect on plant P content.     

Benefit and cost analysis and phosphorus efficiency of VA mycorrhizal fungi colonizations with sorghum (Sorghum bicolor) genotypes grown at varied phosphorus levels

Sorghum [Sorghum bicolor (L.) Moench] was grown in a greenhouse in a low P (3.6 mg kg^-1) soil (Typic Argiudolls) inoculated with the vesicular-arbuscular mycorrhizal fungi (VMAF) Glomus fasciculatum and P added at 0, 12.5, 25.0, and 37.5 mg kg^-1 soil to determine the effects of VAMF-root associations on plant growth, benefit and cost analysis, and P efficiency (dry matter produced/unit P absorbed). Root colonization with VAMF and shoot growth enhancements decreased with increased soil P applications. Mycorrhizal plants were less P efficient than nonmycorrhizal plants. Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants were considered the benefit derived by plants from VAMF-root associations. Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants with similar P concentrations were considered the costs paid by plants for VAMF-root associations. Values of benefit and cost analysis for VAMF-root associations were highest when soil P was lowest and decreased with increasing P applications. Genotypic differences for calculated costs were pronounced, but not benefits. Benefit and cost analysis.may be helpful to evaluate host plant genotypes and VAMF species to optimize efficiencies of VAMF symbiosis in different soil environments.     

Epidemic Development and Virulence in 1995–1998 of Puccinia coronata, a Potential Biocontrol Agent of Wild Oats on San Clemente Island

The biology of islands differs from that of large land masses in having less complex ecosystems. Introduced exotic weeds are often a major threat to fragile island ecosystems because of their expansion into habitats previously occupied by endemic species. San Clemente Island, 120 km off the California coastline, is an example of this process in which numerous exotic weed species have been introduced and some are endangering the native flora. Crown rust of oats caused by Puccinia coronata f.sp. avenae was investigated as a potential biocontrol agent against two wild oat species, Avena barbata and Avena fatua, introduced on San Clemente Island. Epidemiology and virulence of this rust were studied. The island was surveyed from 1995 to 1998 for occurrence of P. coronata on wild oats. Wild oats were found sprouting in the northern part of the island shortly after autumn rainfall and subsequently covered the main grasslands of the island. The rust also appeared first on the northern part of the island and progressively spread south. However, disease severities in the south were considerably lower than those in the north. Diverse virulence types, although related to Californian and Mexican forms, were detected among the isolates. The potential use of P. coronata as an augmentative biocontrol agent for wild oat species on San Clemente Island is discussed.     

European and African maize cultivars differ in their physiological and molecular responses to mycorrhizal infection

Physiological and molecular responses to phosphorus (P) supply and mycorrhizal infection by Glomus intraradices were compared in European (River) and African (H511) maize (Zea mays) cultivars to examine the extent to which these responses differed between plants developed for use in high- and low-nutrient-input agricultural systems. Biomass, photosynthetic rates, nutrient and carbohydrate contents, mycorrhizal colonization and nutrient-responsive phosphate transporter gene expression were measured in nonmycorrhizal and mycorrhizal plants grown at different inorganic phosphorus (P(i)) supply rates. Nonmycorrhizal River plants grew poorly at low P(i) but were highly responsive to mycorrhizal infection; there were large increases in biomass, tissue P content and the rate of photosynthesis and a decline in the expression of phosphate transporter genes. Nonmycorrhizal H511 plants grew better than River plants at low P(i), and had a higher root : shoot ratio. However, the responses of H511 plants to higher P(i) supplies and mycorrhizal infection were much more limited than those of River plants. The adaptations that allowed nonmycorrhizal H511 plants to perform well in low-P soils limited their ability to respond to higher nutrient supply rates and mycorrhizal infection. The European variety had not lost the ability to respond to mycorrhizas and may have traits useful for low-nutrient agriculture where mycorrhizal symbioses are established.     

Effect of arbuscular mycorrhizal colonization and two levels of compost supply on nutrient uptake and flowering of pelargonium plants

Two challenges frequently encountered in the production of ornamental plants in organic horticulture are: (1) the rate of mineralization of phosphorus (P) and nitrogen (N) from organic fertilizers can be too slow to meet the high nutrient demand of young plants, and (2) the exclusive use of peat as a substrate for pot-based plant culture is discouraged in organic production systems. In this situation, the use of beneficial soil microorganisms in combination with high quality compost substrates can contribute to adequate plant growth and flower development. In this study, we examined possible alternatives to highly soluble fertilizers and pure peat substrates using pelargonium (Pelargonium peltatum L’Her.) as a test plant. Plants were grown on a peat-based substrate with two rates of compost addition and with and without arbuscular mycorrhizal (AM) fungi. Inoculation with three different commercial AM inocula resulted in colonization rates of up to 36% of the total root length, whereas non-inoculated plants remained free of root colonization. Increasing the rate of compost addition increased shoot dry weight and shoot nutrient concentrations, but the supply of compost did not always completely meet plant nutrient demand. Mycorrhizal colonization increased the number of buds and flowers, as well as shoot P and potassium (K) concentrations, but did not significantly affect shoot dry matter or shoot N concentration. We conclude that addition of compost in combination with mycorrhizal inoculation can improve nutrient status and flower development of plants grown on peat-based substrates.     

Cycling of nutrients from dying roots to living plants,including the role of mycorrhizas

This paper presents information about the release of nitrogen and phosphorus from dying grass roots and the capture of phosphorus by other, living plants. We have paid particular attention to the part played by mycorrhizas in this phosphorus capture, and the possible importance of mycorrhizal links between dying and living roots.WhenLolium perenne plants were grown with ample nutrients and their roots then detached and buried in soil, about half the nitrogen and two-thirds of the phosphorus was lost in three weeks, but only one-fifth of the dry weight. The C:N and C:P ratios suggest that microbial growth in the roots would at first be C-limited but would become N- and P-limited within three weeks.Rapid transfer of³²P can occur from dying roots to those of a living plant if the two root systems are intermingled. The amount transferred was substantially increased in two species-combinations that are known to form mycorrhizal links between their root systems. In contrast, in a species-combination where only the living (receiver) plant could become mycorrhizal no significant increase of³²P transfer occurred. This evidence, although far from conclusive, suggests that mycorrhizal links between dying and living roots can contribute to nutrient cycling. This research indicates a major difference in nutrient cycling processes between perennial and annual crops.     

Yellow leaf spot of cashew: A case of molybdenum deficiency

Summary Rooted cuttings ofSeverinia buxifolia were inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungusGlomus intraradices or provided an inoculum filtrate (non-VAM plants) and grown in one of seven media combinations of fired montmorillonite clay (FMC) and Canadian peatmoss (CP) at ratios of 100%, 80%, 67%, 50%, 33%, 20%, or 0% FMC. Mycorrhizal infection increased with higher proportions of FMC, but the growth of both VAM and non-VAM plants was reduced with increased FMC amendment. The growth benefit (top and root fresh-dry weights) conferred by mycorrhizal infection was greater at higher levels of FMC in the media. Improved phosphorus uptake by inoculated severinia plants appeared at least partially responsible for increased growth compared to non-VAM plants under conditions of high soluble salts and pH associated with high FMC composition. Florida Agr. Expt. Sta. Journal Series No. 6319.     

Effects of species of VA-mycorrhizal fungi on growth and mineral uptake of sorghum at different temperatures

Sorghum [Sorghum bicolor (L.) Moench] plants were grown in growth chambers at 20, 25 and 30°C in a low P Typic Argiudoll (3.65 µg P g^–1 soil, pH 8.3) inoculated with Glomus fasciculatum, Glomus intraradices, and Glomus macrocarpum to determine effects of vesicular-arbuscular mycorrhizal fungi (VAMF) species on plant growth and mineral nutrient uptake. Sorghum root colonization by VAMF and plant responses to Glomus species were temperature dependent. G. macrocarpum colonized sorghum roots best and enhanced plant growth and mineral uptake considerably more than the other VAMF species, especially at 30°C. G. fasciculatum enhanced shoot growth at 20 and 25°C, and mineral uptake only at 20°C. G. intraradices depressed shoot growth and mineral uptake at 30°C. G. macrocarpum enhanced shoot P, K, and Zn at all temperatures, and Fe at 25 and 30°C above that which could be accounted for by increased biomass. Sorghum plant growth responses to colonization by VAMF species may need to be evaluated at different temperatures to optimize beneficial effects.     

The effect of carbohydrate on the development of a Cattleya hybrid in association with its mycorrhizal fungus

To investigate beneficial effects of mycorrhizal fungi to advanced leafy orchids, growth studies on the development of symbiotic seedlings of the orchid Cattleya (aclandiae x schoeffeldiana) x aclandiae were conducted in vitro over a period of 18 months using split plates with minerals and carbohydrates on one side and water agar on the other. Mycorrhizal infection and shoot and root growth of seedlings on the nutrient side were compared to growth on the water agar side with nutrient uptake by the orchid only possible via external mycorrhizal hyphae. Seed germination was followed by mycorrhizal infection and rapid development of protocorms on both nutrient and non-nutrient sides of the plates. With 0.5% starch, development of protocorms was sustained for a least 12 weeks, compared to only 6 weeks with 0.1% starch. Advanced protocorms with two small leaves and a smoll root were transferred at week 22 to new fungal plates. When harvested at week 43, plantlets on 0.5% starch (both nutrient and water agar sides) had 2.7 times the dry weight of plantlets on 0.1% starch. Shoot-root ratios were higher on the lower level of carbon. In all plantlets, mycorrhizal infection involved less than 5% of the root length. With zero, 0.1% or 0.5% starch, the roots were re-infected on transfer to fresh fungal plates but young roots that developed following the transfer stayed free of infection, Plantlets on 0.5% starch (nutrient and water agar side) after 18 months had longer roots than plantlets grown in the absence of starch or on 0.1% starch. Shoots were small but significantly larger on the nutrient side than on the water agar side, independent of the carbohydrate level. The shoot-root ratio was highest on the nutrient side with no starch present. In this latter case, plantlet development was steady but plantlets on the non-nutrient side developed slowly; thus there was little evidence of nutrient translocation by the mycorrhizal fungus from the nutrient to the non-nutrient side in the absence of carbohydrates. Mycorrhizal infection is discussed as a mechanism for heterotrophic carbon assimilation. In advanced leafy orchids of Cattleya, external carbon resulted in increased root growth, decreased shoot/root ratio and sometimes yellowish-green plantlets.     

Influences of Arbuscular Mycorrhizal Fungus Glomus mosseae on Growth and Nutrition of Lentil Irrigated with Arsenic Contaminated Water

Arsenic (As) contamination of irrigation water represents a major constraint to Bangladesh agriculture. While arbuscular mycorrhizal (AM) fungi have their most significant effect on P uptake, they have also been shown to alleviate metal toxicity to the host plant. This study examined the effects of As and inoculation with an AM fungus, Glomus mosseae, on lentil (Lens culinaris L. cv. Titore). Plants were grown with and without AM inoculum for 9 weeks in a sand and terra green mixture 50:50 v/v and watered with five levels of As (0, 1, 2, 5, 10 mg As L⁻¹ arsenate). Inoculum of Rhizobium leguminosarum b.v. Viceae strain 3841 was applied to all plants. Plants were fed with modified Hoagland solution (1/10 N of a full-strength solution and without P). Plant height, leaf number, pod number, plant biomass and shoot and root P concentration/offtake increased significantly due to mycorrhizal infection. Plant height, leaf/ pod number, plant biomass, root length, shoot P concentration/offtake, root P offtake and mycorrhizal infection decreased significantly with increasing As concentration. However, mycorrhizal inoculation reduced As concentration in roots and shoots. This study shows that growing lentil with compatible AM inoculum can minimise As toxicity and increase growth and P uptake.