AM Species Research Articles

Divergent soil P accrual in ectomycorrhizal and arbuscular mycorrhizal trees: insights from a common garden experiment in subtropical China.

Tree species establish mycorrhizal associations with both ectomycorrhizal (EM) and arbuscular mycorrhizal fungi (AM), which play crucial roles in facilitating plant phosphorus (P) acquisition. However, little attention has been given to the effects of EM and AM species on soil P dynamics and the underlying mechanisms in subtropical forests, where P availability is typically low. To address this knowledge gap, we selected two EM species (Pinus massoniana - PM and Castanopsis carlesii - CC) and two AM species (Cunninghamia lanceolata - Chinese fir, CF and Michelia macclurei - MM) in a common garden established in 2012 in subtropical China. We investigated soil properties (e.g., pH, soil organic carbon, total nitrogen, and dissolved organic nitrogen), soil P fractions, phospholipid fatty acids (PLFAs), enzyme activities, foliar manganese (Mn) concentration, and foliar nutrients and stoichiometry. Our findings revealed that soils hosting EM species had higher levels of resin P, NaHCO3-Pi, extractable Po, total P, and a greater percentage of extractable Po to total P compared to soils with AM species. These results indicate that EM species enhance soil P availability and organic P accumulation in contrast to AM species. Moreover, EM species exhibited higher P return to soil (indicated by higher foliar P concentrations) when compared to AM species, which partly explains higher P accumulation in soils with EM species. Additionally, resin P showed a positive correlation with acid phosphatase (ACP) activity, whereas no correlation was found with foliar Mn concentration, which serves as a proxy for the mobilization of sorbed soil P. Such findings indicate that organic P mineralization has a more substantial impact than inorganic P desorption in influencing P availability in soils hosting both EM and AM species. In summary, our study contributes to a more comprehensive understanding of the effects of mycorrhizal associations on soil P accumulation in subtropical forests and provide valuable insights into plant-soil interactions and their role in P cycling in regions with limited P availability.

Corrigendum

New Phytologist 234 (2022), 1639–1653, doi: 10.1111/nph.18066. Since its publication, the authors of Yan et al. (2022) have identified an error in one of the figures presented in their article. In Fig. 3, the tips representing the mycorrhizal types were assigned incorrect colors. The correct Fig. 3 is shown below. All relevant results and conclusions remain unchanged. The authors take this opportunity to acknowledge concerns about the assignments of mycorrhizal symbiosis. There are two species (Acer truncatum and Ulmus macrocarpa) that should be assigned to AM species according to Steidinger et al. (2019). While the authors were doing the sampling work, these two species were associated with ECM fungi in the study sites. As Sun et al. (2019) notes, the empirical evidence is also a main method to assign plant mycorrhizal types besides the phylogenetic-taxonomic method and species within the same genus or family could have different mycorrhizal types due to the local conditions. To make the detailed information of species more clear, the authors have generated an additional column in Supporting Information Table S1 of abbreviated names to support Fig. 3 as shown below. The tree files used in this study have been updated in Dryad: 10.5061/dryad.j0zpc869s (Yan et al., 2022). We apologize to our readers for this mistake. Corrected Fig. 3 and Supporting Information Table S1 Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Population Response of Rhizosphere Microbiota of Garden Pea Genotypes to Inoculation with Arbuscular Mycorrhizal Fungi.

This study of a legume's rhizosphere in tripartite symbiosis focused on the relationships between the symbionts and less on the overall rhizosphere microbiome. We used an experimental model with different garden pea genotypes inoculated with AM fungi (Rhizophagus irregularis and with a mix of AM species) to study their influence on the population levels of main trophic groups of soil microorganisms as well as their structure and functional relationships in the rhizosphere microbial community. The experiments were carried out at two phenological cycles of the plants. Analyzes were performed according to classical methods: microbial population density defined as CUF/g a.d.s. and root colonization rate with AMF (%). We found a proven dominant effect of AMF on the densities of micromycetes and actinomycetes in the direction of reduction, suggesting antagonism, and on ammonifying, phosphate-solubilizing and free-living diazotrophic Azotobacter bacteria in the direction of stimulation, an indicator of mutualistic relationships. We determined that the genotype was decisive for the formation of populations of bacteria immobilizing mineral NH4+-N and bacteria Rhizobium. We reported significant two-way relationships between trophic groups related associated with soil nitrogen and phosphorus ions availability. The preserved proportions between trophic groups in the microbial communities were indicative of structural and functional stability.

Ectomycorrhizal (dipterocarp) and arbuscular mycorrhizal (non‐dipterocarp) tree hosts and their relative distribution in a tropical forest predict soil bacterial communities

Abstract The type of mycorrhizal associations (i.e. ectomycorrhizal [EM] or arbuscular mycorrhizal [AM]) formed by trees is of fundamental importance for a range of soil properties and processes in forests, yet their importance for the distribution of other important soil biota such as bacteria is largely unknown. We used an experimental common garden and amplicon sequencing to assess how abiotic and biotic variation differentially influenced bacterial communities associated with 13 climax tree species (8 EM members of the Dipterocarpaceae and 5 AM species from different families) planted into a secondary tropical forest in Borneo. Rhizosphere bacterial (RB) communities differed significantly between EM and AM trees but not among EM species and only marginally among AM species. RB communities were related to the density and size of neighbouring EM but not AM trees. Diversity of RB on AM trees responded positively to AM neighbours and negatively to EM neighbours but RB diversity associated with EM trees was unaffected by neighbourhood. Plant‐growth‐promoting taxa of RB assorted similarly to total RB but more strongly. Synthesis. Our results suggest that the distribution of RB communities is associated with plant mycorrhizal type and plant neighbourhood. Because rhizosphere bacteria alter nutrient cycling and influence plant species composition, their distributions are likely important for understanding ecosystem processes and plant demographics in forest ecosystems.

Tree species affect the vertical distribution of soil organic carbon and total nitrogen

AbstractBackgroundForest soils are considered sinks for atmospheric C. Many studies revealed that tree species and their mycorrhizal association affect forest floor and topsoil organic C (OC) and total N, while the knowledge of their effect on subsoil OC and N is still scarce.AimsWe aimed to identify (1) tree species and mycorrhizal association effects on forest floor, topsoil (0–30 cm) and subsoil (30–80 cm) OC and N stocks and vertical distribution and (2) drivers for soil OC and N distribution.MethodsWe sampled forest floor, topsoil and subsoil under Fagus sylvatica L., Quercus robur L., Acer pseudoplatanus L. and Fraxinus excelsior L. in four Danish common garden experiments along a gradient in soil texture and determined OC and N stocks.ResultsTotal N (forest floor + soil) was higher under oak than beech, while total OC was unaffected by species. Forest floor C and N were higher under oak and beech, both ectomycorrhizal species (ECM), compared to under maple and ash, which are both arbuscular mycorrhizal species (AM). Relatively more OC and N were transferred to the topsoil under AM than ECM species, and this could be explained by greater endogeic earthworm biomass in AM species. In contrast, a higher proportion of OC was stored under ECM than AM species in the subsoil, and here OC correlated negatively with anecic earthworms. Subsoil N was highest under oak.ConclusionsTree species and in particular their mycorrhizal association affected the vertical distribution of soil OC and N. Tree species differences in topsoil OC and N were not mirrored in the subsoil, and this highlights the need to address the subsoil in future studies on AM‐ versus ECM‐mediated soil OC and N stocks.

Occurrence of Arbuscular Mycorrhizal Fungi in Mangrove Forest of Achara in Maharashtra, IndiaOF ARBUSCULAR MYCORRHIZAL FUNGI IN MANGROVE FOREST OF ACHARA IN MAHARASHTRA, INDIA

Present work is an attempt to study the arbuscular mycorrhizal fungal diversity of Achara mangrove forest located at Maharashtra on the west coast of India. Of the twelve mangrove species screened for arbuscular mycorrhizal colonization 10 species viz ., Rhizophora apiculata , Rhizophora mucronata (Rhizophoraceae), Sonneratia alba (Sonneratiaceae), Avicennia marina, A. officinalis (Avicenniaceae), Excoecaria agallocha, Aegiceras corniculatum (Euphorbiaceae), Acanthus illicifolius (Acanthaceae) Xylocarpus granatum (Meliaceae) were found to be mycorrhizal. The non mycorrhizal plants were Kandelia candel and Ceriops tagal (Rhizophoraceae). Arbuscular mycorrhizal colonization was found to be maximum in Sonneretia alba (83%), and was least in Avicennia marina (6%). The spore density of AM fungal spores ranged from 14 spores/100g soil in Rhizophora mucronata to 78 spores/100g rhizosphere soil in Excoecaria agallocha .. Among the 15 AM species reported from 12 mangrove species Glomus macrocarpum (66%) was the most frequently occurring AM fungal species followed by Glomus fasciculatum (50%), Glomus claroideum (42%) and Acaulospora laevis (42%).

Decomposition of Meadow and Forest Plant Roots in the Ash Substrate of Power Plant Dumps: A Laboratory Experiment

It is noted that plant roots make a significant contribution to the formation of technozems during self-overgrowing of the technogenic substrate. The rate of decomposition of a mixture of fine roots (<0.5 mm thick) of meadow arbuscular mycorrhiza species (AM) in comparison with forest ecto mycorrhiza species (EM) in the ash substrate from the power station was studied in a 150-day experiment in the laboratory. Differences in the rates of decomposition of root mixtures, as well as in carbon (C) and nitrogen (N) content before and after decomposition in different variations of the experiment, have been revealed. AM species have higher losses of biomass, nitrogen, and carbon in contradistinction to ЕM species.

Biodiversity of arbuscular mycorrhizal fungi associated with selected medicinal plants of Hamirpur district of Himachal Pradesh, India

The present investigation was focused on exploration of biodiversity of Arbuscular mycorrhizal fungi (AMF) associated with different medicinal plants. Twenty-two medicinal plants belonging to 14 families were analyzed for AMF colonization. The plant roots and their respective rhizosphereic soil samples were collected from different localities of hamirpur district, himachal pardesh for AMF analysis and spore assessment per 50gm of soil sample of soil. The results revealed that number of AM spores in the rhizosphere of plant was not related to percent of AM root colonization. Highest per cent of root colonization was reported in Ricinus communis (86.5±4.68 %) and Achyranthes aspera lacks colonization. Highest number of AM spore was found in rhizosperic soil sample of Mimosa pudica (177.4±4.306) and least number of spores in Datura stramonium (47.53±2.76). Fourty three AM species belonging to five genera i.e. Glomus, Acaulospora, Gigaspora, Entrophospora and Sclerocystis were isolated during investigation. Maximum AM spore diversity was observed in Mentha viridis followed by Catharanthus roseus and least diversity related to Datura stramonium. The study confirmed that diversity of AM fungi varies with plant to plant.

Facultative mycorrhizal associations promote plant naturalization worldwide

AbstractMycorrhizal symbiosis has received relatively little attention as a mechanism explaining plant naturalizations at a global scale. Here, we combined data on vascular plant species occurrences in over 840 mainland and island regions from the Global Naturalized Alien Flora (GloNAF) database with up‐to‐date databases of mycorrhizal associations. We tested whether the mycorrhizal type (arbuscular, AM; ectomycorrhizal, ECM; and non‐mycorrhizal, NM) and status (facultative and obligate) were associated with two measures of naturalization success, (1) naturalization incidence (reflecting the ability to naturalize, and expressed as whether or not a plant species is recorded as naturalized anywhere in the world) and (2) naturalization extent (expressed as the number of GloNAF regions where the species occurs). In total, we found information on mycorrhizal type and status for 3211 naturalized plant species and 4200 non‐naturalized plant species. Mycorrhizal plant species, both AM and ECM, were more likely to be naturalized and naturalized to a greater extent than NM plants. The effect of being an AM species was always stronger, with AM species having a greater naturalization extent than ECM species. Being the same mycorrhizal type or status, annual species were generally more likely to be naturalized than perennials. Species with facultative mycorrhizal associations were more successful than those with obligate mycorrhizal associations, but both groups tended to have a greater chance of being naturalized than NM species. These results indicate that being NM is generally less favorable for naturalization. Overall, our results confirm, at the global scale, those of regional studies that facultative association with AM provides plant species with a naturalization advantage. For the first time, we have shown that being mycorrhizal contributes not only to the size of the naturalized range, reflecting the ability to spread, but also to the ability to become naturalized in the first instance.

ARBUSCULAR MYCORRHIZAL FUNGAL-ASSOCIATED BACTERIA AFFECT MYCORRHIZAL COLONIZATION, ESSENTIAL OIL AND PLANT GROWTH OF Murraya koenigii L.

Murraya koenigii L. (family: Rutaceae) commonly called as curry leaf is a highly valued plant for aroma and medicinal value. The two dominant AM species Glomus mosseae and Acaulospora laevis were isolated from the rhizospheric soil of M. koenigii. A pot experiment was performed to see the interactive potential of G. mosseae and A. laevis alone or in combination with Pseudomonas fluorescens on M. koenigii. Various morphological and biochemical parameters were measured after 120 days. Overall results suggest that although, all co-inoculation treatments showed beneficial effects on all the growth, physiological and oil content. The overall results demonstrate that the co-inoculation of bioinoculants like P. fluorescens with AM fungi promotes higher AM colonization and spore number enhancing nutrient acquisition especially phosphorus (P), improving the rhizospheric condition of soil.

Arbuscular Mycorrhizal and endophytic (DSE) association in the dominant grasses of Melghat forest (Phase -I), India

Investigations on arbuscular mycorrhizal Fungi (AMF) and dark septate endophytic (DSE) association in some of the dominant grasses from Melghat forest (phase I) of Satpura terrain India, was carried out to examine their existence and symbiotic relationships with the host plants. This forest area was not surveyed earlier by anybody to evaluate the AMF status diversity hence it was decided to survey the buffer and core area. Rhizosphere soil of each sampled grass was analyzed for the AM fungal structures in the roots to study percent root colonization by AMF and AMF spore density in rhizospheric soils of respective samples. The composite soil sample was prepared for each site and used for physicochemical analysis by standard methods. In the first phase of project, forty-eight dominant grass species from twenty-one different sites were collected along with roots and rhizospheric soil to find out AMF and DSE status of grasses. Both type of fungal associations was found in almost all the grass species collected during studies. All of them were found colonized by AMF hyphae along with moderate to poor development of mycorrhizal structures in roots. DSE colonization was also found in maximum forty-three grasses. Physico- chemical characterization of all the soil samples were performed to find out its correlation with AM percent colonization and spore count. Mean AMF percent colonization were in between 1.33 to 52.85 and DSE in with 0.00 to 18.97. Viable AM spore count were in between 0 to 98 per 100g of soil. Altogether four AMF genera with its thirty-nine-different species were isolated and identified.&#x0D; A data base of indigenous AM species richness for Melghat forest has been generated to plan and design the future management practices for grasses establishment and development especially in burnt and over grazed areas.

Greater variations of rhizosphere effects within mycorrhizal group than between mycorrhizal group in a temperate forest

The presence of living roots can markedly change soil properties, microbial activities, and biogeochemical cycling in the rhizosphere compared to bulk soil. Such rhizosphere effect has been increasingly recognized to play a crucial role in carbon (C) and nitrogen (N) cycling in terrestrial ecosystems. Here, we investigated the rhizosphere effects of 12 tree species associated with two contrasting mycorrhizal types (arbuscular mycorrhizal, AM vs. ectomycorrhizal, ECM) and co-occurring in a temperate secondary forest in Northeast China. The adhering soil method was adopted to sample paired rhizosphere and bulk soils of field-grown trees in the peak growing season. Generally, we found positive rhizosphere effects on soil properties (ammonium and nitrate content, total C and N content, and C:N ratio), microbial abundances (bacteria, fungi, and actinomycetes), enzyme activities (C- and N-degradation enzymes), and C mineralization rate (Cmin), but minor rhizosphere effects on soil pH, phosphorus content and phosphatase activity, net N mineralization rate (Nmin), and specific Cmin and Nmin (per unit soil C or N). Because of large intraspecific and particularly interspecific variations, less than half of the rhizosphere effects were statistically significant (P < 0.05), and none of the rhizosphere effects differed significantly between the two mycorrhizal types (AM vs. ECM). Moreover, most soil variables varied greatly within and across species, and thus did not differ significantly between the two mycorrhizal types (AM vs. ECM). However, soil pH, nitrate content, microbial abundance, and C-degradation enzyme activity were notably lower under ECM species than under AM species. Collectively, these results show that rhizosphere effects varied greatly among the six species within both mycorrhizal groups, and such variations within mycorrhizal group were even larger than those between mycorrhizal group. Future work should include a larger number of tree species to increase statistical power, and combine phylogenic history and functional traits of plant species with the type and traits of mycorrhizal fungi to better understand how plant-microbe interactions influence biogeochemical cycling in the rhizosphere.

Nanosecond pulsed electric fields promoting the proliferation of porcine iliac endothelial cells: An in vitro study.

Currently, nanosecond pulsed electric fields (nsPEFs) with short pulse duration and non-thermal effects have various potential applications in medicine and biology, especially in tumor ablation. Additionally, there are a few investigations on its proliferative effects in the normal cell. Clinically, proliferation of endothelial cells can perhaps accelerate the stent endothelialization and reduce the risk of acute thrombosis. To explore the feasibility using nsPEFs to induce proliferation of endothelial cells, in this study, porcine iliac endothelial (PIEC) cell line was cultured and tested by CCK-8 assay after nsPEFs treatment. The results reflected that nsPEFs with low field strength (100ns, 5 kV/cm, 10 pulses) had a significant proliferative effect with an increase in the PIEC cell growth of 16% after a 48 hour’ post-treatment. To further understand the mechanism of cell proliferation, intracellular Ca2+ concentration was measured through fluo-4 AM and reactive oxygen species assay was applied to estimate the level of intracellular reactive oxygen species (ROS). Finally, the total nitric oxide assay for NO production in the cultured medium was evaluated. An enhanced concentration of intracellular Ca2+ and ROS were observed, while the concentration of extracellular NO also increased after nsPEFs treatment. Such experimental results demonstrated that nsPEFs with appropriate pulse parameters could effectively enhance cell proliferation on PIEC cells, and the cell proliferation associated strongly with the changes of intracellular Ca2+ concertation, ROS and NO production induced by nsPEFs treatment. This in vitro preliminary study indicates that as a novel physical doping, the nsPEFs have potential in stimulating endothelial cells to accelerate stent endothelialization.

Patterns in spatial distribution and root trait syndromes for ecto and arbuscular mycorrhizal temperate trees in a mixed broadleaf forest.

Functional differences between trees with arbuscular (AM) or ectomycorrhizal (ECM) partnerships influence important ecological processes including nutrient cycling, community assembly, and biomass allocation patterns. Although most broadleaf temperate forests show both mycorrhizal types, relatively few studies have addressed functional difference among coexisting mycorrhizal tree species. The maintenance of ECM associations usually requires higher C investment than AM, leading to (A) lower root biomass and (B) more conservative root trait syndromes in ECM tree species compared to AM species. Here we quantified the representation and trait syndromes of 14 canopy tree species associated with either AM or ECM fungi in a natural forest community. Our results showed that, whereas species root abundance was proportional to basal area, some ECM tree roots were largely under-represented (up to ~33%). Most of the under-representation was due to lower than expected root abundance of Quercus rubra and Fagus grandifolia. Functional root traits in tree species were similar, with the exception of higher tissue density in ECM species. Moreover, closely related AM and ECM exhibited similar traits, suggesting inherited trait syndrome from a common ancestor. Thus, we found little evidence of divergent functional root trait syndromes between mycorrhizal types. Cores dominated by ECM species influenced trait distribution at the community level, but not total biomass, suggesting that mycorrhizal affiliation may have a stronger effect on the spatial distribution of traits but not on biomass stocks. Our results present an important step toward relating belowground carbon dynamics to species traits, including mycorrhizal type, in broadleaf temperate forests.

Determinants of 15N Natural Abundance in Leaves of Co-Occurring Plant Species and Types within an Alpine Lichen Heath in the Northern Caucasus

Several factors may have interactive effects on natural 15N abundance of plant species. Some of these effects could be associated with different plant functional types, including mycorrhizal association type. Due to its high taxonomic and functional diversity, the alpine heath community in the Caucasus is a suitable object for studying 15N natural abundance of plants in relation to different functional/mycorrhizal groups, contrasting with the limited numbers of plant groups or species considered in previous studies of individual communities. The N concentration and δ15N were determined in leaves of 25 plant species from 8 functional/mycorrhizal groups from an alpine lichen heath in the Teberda Reserve, Northern Caucasus, Russia. Functional groups were represented by ericoid mycorrhizal species (ERI), ectomycorrhizal species (ECT), arbuscular mycorrhizal forbs (AM—FORB), arbuscular mycorrhizal grasses (AM—GRA), arbuscular mycorrhizal nodulated legumes (FAB—N), non-mycorrhizal graminoids (sedges and rushes) (NOM—GRA), non-mycorrhizal hemiparasites (NOM—SP), and orchids (ORC). We can summarize our results in two rankings for leaf N concentration (FAB—N > ORC > AM—FORB, ECT > NOM—SP, ERI ≥⃒ NOM—GRA, AM—GRA) and leaf δ15N signature (ORC > NOM—GRA, FAB—N > ECT ≥⃒ ERI ≥⃒ AM—FORB, NOM—SP, AM—GRA) of alpine heath species. We conclude that, within the alpine lichen heath in the Northern Caucasus, the δ15N signature of plant foliage is a relevant indicator of plant functional groups with relatively high 15N content (ORC, FAB-N, NOM-GRA), while the absence of a significant difference between relatively 15N-depleted groups (AM, ERI, and ECT species) isn't clear and may result from both processes, as the increased N isotope fractionation by arbuscular mycorrhizal fungi as the decreased role of ecto- and ericoid mycorrhizal fungi in the flux of N.

Arbuscular mycorrhizal fungal communities are phylogenetically clustered at small scales.

Next-generation sequencing technologies with markers covering the full Glomeromycota phylum were used to uncover phylogenetic community structure of arbuscular mycorrhizal fungi (AMF) associated with Festuca brevipila. The study system was a semi-arid grassland with high plant diversity and a steep environmental gradient in pH, C, N, P and soil water content. The AMF community in roots and rhizosphere soil were analyzed separately and consisted of 74 distinct operational taxonomic units (OTUs) in total. Community-level variance partitioning showed that the role of environmental factors in determining AM species composition was marginal when controlling for spatial autocorrelation at multiple scales. Instead, phylogenetic distance and spatial distance were major correlates of AMF communities: OTUs that were more closely related (and which therefore may have similar traits) were more likely to co-occur. This pattern was insensitive to phylogenetic sampling breadth. Given the minor effects of the environment, we propose that at small scales closely related AMF positively associate through biotic factors such as plant-AMF filtering and interactions within the soil biota.

Arbuscular mycorrhiza and plant succesion on zinc smelter spoil heap in Katowice-Wełnowiec

Mycorrhizal status of plants colonising the zinc wastes in Katowice was surveyed. In total 69 vascular plant species (25 families) appearing on the investigated area have been noted. More than 60% of them were mycorrhizal. Non-mycorrhizal species, such as &lt;em&gt;Cardaminopsis arenosa&lt;/em&gt; and &lt;em&gt;Silene vulgaris&lt;/em&gt; dominated the early successional part of the zinc heap. &lt;em&gt;Tussilago farfara&lt;/em&gt; was the only AM plant there, however, no arbuscules were developed at this stage. The number of AM species was increased on the 20 years old part of the zinc wastes and on the older 30-50 years old areas. AM plants constituted about 60% of the total number of species there. The frequency of particular AM species was the highest on the oldest part of the investigated area. The usefulness of the results for restoration practices was discussed.

CORN (ZEA MAYS L.) GROWTH AS AFFECTED BY SOIL COMPACTION AND ARBUSCULAR MYCORRHIZAL FUNGI

A two-year research work was performed under greenhouse conditions to evaluate: 1) the effects of soil compaction on corn growth, and 2) if using different species of mycorrhizal fungi under non-sterilized and sterilized conditions can alleviate the stress of soil compaction on corn growth. After sieving the field soil and sterilizing half of it using an autoclave, it was compacted in 2-kg pots. The soil was then planted with corn seeds and inoculated with different species of AM species including Glomus etunicatum, G. mosseae, and G. intraradices. While high levels of soil compaction decreased corn growth, AM inoculation significantly enhanced root and shoot growth and hence plant growth under compaction and G. etunicatum was the most efficient one. These results are important complementary to the previously little documented results regarding the effects of AM fungi on corn growth under compaction stress and are of agricultural and ecological significance.

Effects of arbuscular mycorrhizal fungal species and the medium pH on the growth of Pueraria phaseoloides (Roxb.) Benth

Soil conditions may change the response of plants to inoculation with arbuscular mycorrhizal fungi (AMF). This, in turn, may influence the development of mycorrhizal associations. The effect of AM species isolated from different ecosystems was evaluated on Pueraria phaseoloides (kudzu). Experiments were conducted under controlled conditions in Leonard jars, on a substrate made of peat, rice husk, and vermiculite (1-1-1) enriched with rock phosphate plus a modified Hoagland nutrient solution. In the first experiment the initial pH of the substrate (8.0) was reduced by approximately one unit by inoculation with Kuklospora colombiana, Glomus clarum, and Glomusmanihotis. The result was the same for Acaulospora longula species when 4-morpholine ethanesulphonic acid (MES) buffer was used. The final pH of the substrate was correlated with the above-ground plant biomass production suggesting that the most effective fungus regulated the pH of the substrate. This positive interaction leads to a higher concentration of P and K in plants. When the pH of the substrate was buffered with MES, in the second experiment, the efficiency of K. colombiana was reduced, even though plants inoculated with this fungus yielded more than non-inoculated plants. G. intraradices and A. longula were favoured by buffer addition. Beneficial buffer effects on this plant resulted in lower pH, better plant P and K uptake, and higher biomass production. The best plant yield was obtained at pH 7.0 in both experiments. G. clarum and G. manihotis yielded the highest biomass production. Under the proposed conditions, AMF improved P. phaseoloides growth and pH regulation. These growth conditions may be used for the evaluation and propagation of some AMF species adding MES buffer in the nutrient solution.

Native AM fungal colonization in three Hibiscus species under NaCl induced Salinity

The pot experiments were conducted to study influence of sodium chloride salinity on Native Arbuscular Mycorrhizal fungal consortium (NAMC) with respect to three Hibiscus species viz., H. cannabinus, H. sabdariffa and H. tiliaceus (Fam. Malvaceae). All three plant species exhibited appreciable colonization and showed excellent salt tolerance potential at 300 mM NaCl treatment. Results obtained revealed that Arbuscular Mycorrhizal fungal (AM) species spore recovery (SR) was in the range of 50-100% in treated plants. AM species studied in present paper were viz., Claroideoglomus etunicatum, Sclerocystis coremoides (H. cannabinus); Acaulospora myriocarpa, Acaulospora spp. (H. sabdariffa) and Acaulospora foveata, Acaulospora spp., C. etunicatum, Glomus botryoides, G. caledonicum & G. formosanum (H. tiliaceus).