Arbuscular Mycorrhizal Status Research Articles

EKSPLORASI FUNGI MIKORIZA ARBUSKULA (FMA) PADA RHIZOSFER POHON SAMAMA (Anthocephalus macrophyllus (Roxb.) Havil)

ABSTRACT
 Samama (Anthocephalus macrophyllus) is a wood-producing tree with fast growth. Arbuscular mycorrhizal fungi status (AMF) can associate well with samama plants. This study aimed to determine the diversity of the genus and the number of spores of AMF in the rhizosphere of the samama plant, which has different soil types and environmental factors. The method used to obtain AMF spores was a wet filter pour and centrifugation technique at the center for plant seeds and plant protection for two months. Based on the research results in the village of Poka, it was found that there were four AMF genera with a total of 235 spores. Hatusua village found two genera of FMA with a count of 141 spores. In the village of Uraur, three genera of FMA were found with 479 spores. AMF spore production is influenced by the type of fungus and temperature, sunlight, soil pH, aeration, and water. The presence of mycorrhizae can increase soil fertility as a biological agent.

Density of Arbuscular Mycorrhizal Fungi and Nutrient Status of Soils in Selected Land Use Types and Soil Depths

Density of Arbuscular Mycorrhizal Fungi and Nutrient Status of Soils in Selected Land Use Types and Soil Depths

Root and arbuscular mycorrhizal effects on soil nutrient loss are modulated by soil texture

Despite their importance, there is a lack of knowledge on the impact of forming arbuscular mycorrhizas (AM) on soil phosphorus (P) leaching in soils with different textures. Therefore, the objective of this study was to investigate the impacts of mycorrhizal and non-mycorrhizal roots on P leaching in two non-sterilised soils of contrasting texture. A mycorrhiza-defective tomato (Solanum lycopersicum L.) genotype (named rmc), and its wild-type progenitor that is able to form AM (named 76R), were used to investigate the effects of AM on soil P loss via leaching. Concentrations of reactive and un-reactive P in the leachate and soil were measured and related to plant growth, plant P uptake, soil water relations and leachate dissolved organic carbon (DOC) concentration. Soil texture affected mycorrhizal colonization, plant growth and plant P concentration, and influenced the concentration and chemical composition of P and the concentration of DOC leached. The chemical composition of P leached and P remaining in soil varied with soil texture, the presence or absence of roots, and their arbuscular mycorrhizal status. Mycorrhizal plants reduced P lost via leaching in the sandy soil substrate, where DOC leached was also high. The roots, regardless of mycorrhizal colonization, appeared to have the greatest impact on increasing P and DOC leached. Taken together, this study provides new insights into the role of AM on soil P loss via leaching in soils of contrasting texture.

The arbuscular mycorrhizal fungi status of selected tree nurseries in the Ethiopian highlands

We investigated the arbuscular mycorrhizal fungi (AMF) status of ten nurseries suitable for restoration of dry evergreen Afromontane forests in Ethiopia. We quantified AMF root colonization (RC) and spore abundance (SA) in seedlings of nine native tree species namely Acacia abyssinica Hochst. ex Benth., Cordia africana Lam., Dovyalis abyssinica (A. Rich.) Warb., Hagenia abyssinica J.F. Gmel., Juniperus procera Hochst. ex Endl., Millettia ferruginea (Hochst.) Baker, Olea europaea L. subsp. cuspidata (Wall. ex G. Don) Cif., Podocarpus falcatus (Thunb.) R. Br. ex Mirb. and Prunus africana (Hook. f.) Kalkman. We used the ink and vinegar method to stain AMF in roots. RC levels ranged from 8.00 to 99.67% and were generally higher than the RC levels reported from other similar nurseries in Ethiopia. SA levels ranged from 1 to 25 spores g−1 and were comparable with some reports from the field in Ethiopia but they were lower than levels reported by another similar study. RC was more affected by host species than nursery location, while the reverse was true for SA. The results also showed that nursery management could improve AMF status among seedlings. When all nursery tree species were considered, RC and SA levels were unrelated. No strong correlation existed between the nursery management variables considered and RC or SA. However, considering C. africana, J. procera and P. falcatus separately, RC-age (rs = 0.829, P = 0.042) correlation for O. europaea and RC-pot diameter (rs = 0.820, P = 0.046), RC-pot volume (rs = 0.928, P = 0.008) and SA-age (rs = 0.943, P = 0.005) correlations for C. africana, were significant, strong and positive. Generally, most of the tree species and particularly, early-mid successional tree species had sufficient AMF inoculum. Hence, only the mid-late successional tree species; J. procera, P. falcatus, and P. africana may require AMF inoculation, preferably, during filed planting. Based on our results, age and pot volume were identified to be important variables potentially affecting RC and SA. To better understand the effects of these and other nursery management variables, additional study is required. We demonstrated for the first time that black Hero ink is suitable for staining root AMF and can be used in future AMF research.

Assessment of Local and Systemic Changes in Plant Gene Expression and Aphid Responses during Potato Interactions with Arbuscular Mycorrhizal Fungi and Potato Aphids.

This research examined aphid and plant responses to distinct levels (none, low, and high) of arbuscular mycorrhizal (AM) fungal root colonization by studying the association between potato aphids (Macrosiphum euphorbiae), potatoes (Solanum tuberosum), and AM fungi (Rhizophagus intraradices). It extends knowledge on gene expression changes, assessed by RT–qPCR, of ten defense-related genes at two time-points post-herbivory (24 h and 10 days), focusing on aphid-infested local leaves, non-infested systemic leaves, and roots. The results showed that aphid fitness was not altered by AM symbiosis. At 24 h, ETHYLENE RECEPTOR 1 gene expression was repressed in roots of aphid-infested non-mycorrhizal plants and aphid-infested plants with a high level of AM fungal root colonization, but not on aphid-infested plants with a low level of AM fungal root colonization. At 10 days, ALLENE OXIDE CYCLASE and POTATO TYPE I PROTEASE INHIBITOR were upregulated exclusively in local leaves of aphid-infested plants with a low level of AM fungal root colonization. In addition, local and systemic changes in plant gene expression appeared to be regulated exclusively by AM status and aphid herbivory. In summary, the gene expression data provide insights on mycorrhizal potato responses to aphid herbivory and serve as a starting point for future studies using this system.

Dual-mycorrhizal plants: their ecology and relevance.

Dual-mycorrhizal plants are capable of associating with fungi that form characteristic arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) structures. Here, we address the following questions: (1) How many dual-mycorrhizal plant species are there? (2) What are the advantages for a plant to host two, rather than one, mycorrhizal types? (3) Which factors can provoke shifts in mycorrhizal dominance (i.e. mycorrhizal switching)? We identify a large number (89 genera within 32 families) of confirmed dual-mycorrhizal plants based on observing arbuscules or coils for AM status and Hartig net or similar structures for EM status within the same plant species. We then review the possible nutritional benefits and discuss the possible mechanisms leading to net costs and benefits. Cost and benefits of dual-mycorrhizal status appear to be context dependent, particularly with respect to the life stage of the host plant. Mycorrhizal switching occurs under a wide range of abiotic and biotic factors, including soil moisture and nutrient status. The relevance of dual-mycorrhizal plants in the ecological restoration of adverse sites where plants are not carbon limited is discussed. We conclude that dual-mycorrhizal plants are underutilized in ecophysiological-based experiments, yet are powerful model plant-fungal systems to better understand mycorrhizal symbioses without confounding host effects.

Arbuscular mycorrhizal (AM) status in urban wetland plants and its impact factors

Urban wetlands play an important role in improving urban environment and microclimate, while they are suffering degradation and destruction during urbanization process. Arbuscular mycorrhizae may enhance plant tolerance to environmental stresses and increase vegetation restoration in wetlands. However, presently little is known how about arbuscular mycorrhizal (AM) symbiosis in urban wetland plants and the factors affecting AM formation. Here, a survey for AM status in urban wetland plants was done in Beijing area, and the factors affecting AM formation were also discussed, such as water and sediment characteristics. Results showed that 87.5% of plants (49 of 56 species) were colonized by AM fungi. Mycorrhizal colonization rates (MCRs) ranged from 2% to 72%, while most of them were low level (<25%). The highest mycorrhizal colonization rate (MCR) was observed in Tephroseris palustris. Relationships between MCRs and water properties as well as sediment properties were analyzed by Pearson’s correlation analysis. MCRs in Phragmites australi were negatively correlated with water ammonium nitrogen and a total dissolved phosphorus, while were positively correlated with nitrate nitrogen, nitrite nitrogen and total organic carbon (TOC) in sediment. MCRs in Typha orientalis were negatively correlated with water oxidation-reduction potential while were positively correlated with sediment TOC. MCRs in Glyceria maxima were positively correlated with sediment nitrate nitrogen. MCRs showed seasonal and temporal shift, while the variation was related to plant species. This study indicates that AM symbiosis widely exists in urban wetland plants, while AM formation in various plants is affected by different water and sediment properties.

Diversity of AM fungi in certain ornamental plants growing at different sites of Allahabad, Uttar Pradesh, India.

Use of flowers in Indian cultural and religious purposes has a central place in people’s daily lifestyle. In India, increasing demand and supply of various types of flowers opened a vast scope for the production of flowers. In the present study, five important ornamental plants were collected from five different sites of Allahabad, Uttar Pradesh for the survey purpose to investigate arbuscular mycorrhizal status and diversity. All the ornamental plant species were found to be mycorrhizal but the magnitude of infection varied with the sites, plants species as well as stages of plant growth. A total of 38 species belonging to four different genera of AM fungi were isolated. Glomus was recorded as the most dominant genus with 22 species, followed by Acaulospora with 14 species, sporocarp of Sclerocystis sinuosa and Scutellospora with a single unidentified species. Study of Shannon Weiner diversity index, Species richness and Species evenness also carried out in all the five sites. Diversity of all the sites showed less variation indicating a stable and a diverse fungal community.

Widely distributed native and alien plant species differ in arbuscular mycorrhizal associations and related functional trait interactions

It is debated whether alien plants in new environments benefit from being mycorrhizal and whether widely distributed natives and aliens differ in their associations with mycorrhizal fungi. Here, we compared whether species differing in their origin status, i.e. natives, archaeophytes (alien species introduced before the year 1500) and neophytes (introduced after the year 1500), and arbuscular mycorrhizal (AM) status (obligate, facultative, non‐mycorrhizal) differ in their area of occupancy in Germany (i.e. number of occupied grid cells, each ~130 km²). We used generalized linear models, incorporating main effects and up to three‐way interactions combining AM status, origin status and plant functional traits. The latter were chosen to describe the possible trade‐off in carbon allocation either towards the symbiosis or to other plant structures, such as storage organs (significant interactions involving traits were assumed to indicate the existence of such trade‐offs). AM status significantly explained the area of occupancy of natives and neophytes – with facultative mycorrhizal species occupying the largest area in both groups – but was less pronounced among archaeophytes. Archaeophytes may have reduced dependency on AM fungi, as they are generally agricultural weeds and the symbiosis potentially becomes obsolete for plants growing in habitats providing a steady provision of nutrients. Trait interactions between AM status and other functional traits were almost exclusively detected for neophytes. While facultative mycorrhizal neophytes benefit from trade‐offs with other traits related to high C cost in terms of area of occupancy, such trade‐offs were almost absent among natives. This indicates that natives and neophytes benefit differently from the symbiosis and suggests that native AM fungal partners might be less important for neophytic than for native plant species or that more time is required to establish similar relationships between neophytes and native fungal symbionts.

Shifts in composition and diversity of arbuscular mycorrhizal fungi and glomalin contents during revegetation of desertified semiarid grassland

Arbuscular mycorrhizal (AM) fungi may facilitate the revegetation of degraded ecosystems by decreasing abiotic and biotic stresses on pioneer plants. In addition to assessing the AM status of pioneer plants, monitoring the dynamics of an AM fungal community after revegetation can provide key information for the selection of plant-AM fungal combinations that adapt to the disturbed conditions to promote the establishment and growth of mycorrhizal-dependent pioneer plants. Accordingly, species composition, diversity, and spore density of the AM fungal community inhabiting the root zones of 12-year- and 30-year-old planted Caragana microphylla were determined in the desertified grassland in northern China. Moreover, the content of glomalin-related soil proteins (GRSP) was measured to assess AM fungal biomass. A total of 23 AM fungal species belonging to Acaulospora, Claroideoglomus, Dentiscutata, Funneliformis, Glomus, Rhizophagus, and Septoglomus, were identified. Soil phosphorus availability or organic-carbon content significantly affected AM fungal composition and diversity. However, edaphic properties can explain only approximately 30% of the variations in the AM fungal community. Spore density and GRSP content recorded at the 30-year revegetated dune were significantly higher than those at the 12-year revegetated dune. No significant differences in community composition and diversity of AM fungi were recorded at the dunes with different revegetation duration. This indicates that there might be a certain degree of host-specificity existing in the C. microphylla-AM fungal association. Both taxonomic and phylogenetic analyses should be performed in further research to obtain comprehensive information about the composition and dynamics of an AM fungal community during revegetation of the desertified grassland.

Mycorrhizal status of selected herbaceous plants in Molinia meadows of Folusz, near Szubin (Poland)

This preliminary study examined the arbuscular mycorrhizal (AM) status of native plant species in the Molinia meadows of Folusz in the Kujawy region, Poland. Root samples from ten plant species characteristic of Molinia meadows ( Betonica officinalis , Dianthus superbus , Galium boreale , Inula salicina , Ostericum palustre , Sanguisorba officinalis , Selinum carvifolia , Serratula tinctoria , Silaum silaus , and Succisa pratensis ) were collected in August 2014. Root colonization by AM fungi was considered an indicator of symbiosis development. AM was found in all plant species examined. The frequency of mycorrhizal structures ranged between 68% and 99%. The intensity of mycorrhizal colonization in roots varied with the plant species, ranging between 3.9% ( O. palustre ) and 40.1% ( B. officinalis ). To our knowledge, this is the first study to examine the mycorrhizal status of three species: D. superbus , O. palustre , S. carvifolia . Because AM colonization depends on plant genotype and environmental factors, further studies should examine seasonal variability in plant root colonization and the compositions of AM fungal communities, which may serve as indicators of site conditions

Positive feedback with mycorrhizal fungi alleviates negative effects of intercropping the energy crop Jatropha curcas with Crotalaria retusa

Little is known about the arbuscular mycorrhizal status of the ligneous plant Jatropha curcas, an energy crop that raises high expectations worldwide. We hypothesized that its early mycorrhization and growth could be improved by co-culturing it with Crotalaria retusa, a mycotrophic legume species. Soil samples collected from a 15-year-old J. curcas hedgerow were transferred to the greenhouse, along with soil sampled from the contiguous fallow field. Three pot-culture modalities were studied for 3 months: jatropha alone, jatropha sowed after the clipping of 2-month-old C. retusa, and jatropha sowed next to 2-month-old C. retusa. J. curcas biomass was significantly lower when it was co-cultured with C. retusa in both soil types as compared to when it was grown individually, while its biomass following the cut of C. retusa was not impacted. J. curcas shoot P content was significantly improved only when both plant species grew in the hedgerow soil, and so was mycorrhization intensity. Additionally, the composition of the J. curcas root mycorrhizal community was closer to that of C. retusa when using this hedgerow soil. Overall, J. curcas development was not improved by its association with C. retusa, but the soil cropping history appeared essential to their mycorrhizal interactions. These were favored by a soil mycorrhizal community shaped by multiple years of J. curcas monoculture. Improved knowledge about these preferential association patterns with J. curcas is needed to improve its co-culture with compatible mycotrophic legumes.

Distribution patterns of arbuscular mycorrhizal and non-mycorrhizal plant species in Germany

We analysed the spatial distribution patterns of plant species’ arbuscular mycorrhizal status across an intermediate geographical scale (i.e. the country of Germany) and related these distributions to environmental drivers. Three levels of arbuscular mycorrhizal status of plant species could be defined: (1) obligate arbuscular mycorrhizal species that are always colonised by mycorrhizal fungi, (2) facultative arbuscular mycorrhizal species that are colonised under some conditions but not colonised under others and (3) non-mycorrhizal species that are never found to be colonised by mycorrhizal fungi. We aimed to investigate whether plant species assemblages at the studied grid cell scale are composed of different proportions of species regarding their arbuscular mycorrhizal status, and whether the variation of these proportions can be linked to the geographical variation of ecological and environmental factors. We fitted a vector generalised additive model (VGAM) for log-ratios of proportions of plant species’ arbuscular mycorrhizal status per grid cell (2859 grid cells, each c. 130km2). The spatially explicit plant arbuscular mycorrhizal status distribution model was based on environmental predictors related to climate, geology and land use. The spatial distribution of plant arbuscular mycorrhizal status can be explained as a function of nine environmental predictors (D2=0.54). Proportion of obligate arbuscular mycorrhizal plant species per grid cell increased with increasing temperature range, mean annual temperature, urban area and area of lime as geological parent material and decreased with increasing area of mixed forest and coniferous forest. Annual temperature range was by far the most important predictor. These results extend the comparative context of former studies that established relationships between mycorrhizal status and other plant characteristics at species level, including those describing species ecological requirements, to a context at the level of assemblages and species distributions. We encourage integrating plant mycorrhizal status as a functional trait in future macroecological analyses.

Arbuscular mycorrhizal status of pioneer plants from the mouth of lake Budi, Araucanía Region, Chile

Abstract Arbuscular mycorrhizal fungi (AMF) have an important role on the ecosystem stability promoting water and nutrient acquisition by plants and allowing their growth under stress conditions including drought and salinity. This study aimed at describing the colonization of native AMF associated to pioneer plant species growing at the mouth of lake Budi, which receive seasonally marine water. For this, root samples and rhizosphere substrate of Polygonum maritimum, Carpobrotus chilensis, Ambrosia chamissonis, Ammophyla arenaria were collected and analyzed. Mycorrhizal root colonization, spore and hyphal density, and some soil chemical properties (pH, conductivity, organic matter -OM-, and microbial activity) were determined. Results showed that A. Arenaria presented the highest root colonization (53%), mycelium (10 m g-1) and AMF spores (300 spores in 100g of substrate) densities, which were highly correlated with an elevated OM content (1.64%; r=0.53, r=0.48 y r=0.87, respectively) and soil microbial activity (3.57 µg fluoresce in g-1 h-1; r=0.89 r=0.76 and r=0.53, respectively). On the other hand, a low AMF species richness was found in the rhizospheric soils of all four evaluated plants, finding a total of five AMF species. Nevertheless, one of these corresponds to a new specie (Corymbiglomus pacificum), which was associated to A. arenaria. Our results suggest an important role of AMF associated to pioneer plants in saline ecosystems, especially enhancing the establishment of A. arenaria and Amb. chamissonis, which could promote a further nurse effect that allow the establishment of other plant species. AM fungi could be considered as a biotechnological tool since they could be used for stabilization of coastal ecosystems, and in soils under saline or hydric limitations.

Response of Arbuscular Mycorrhizal Fungi in Different Soil Tillage Systems to Long‐Term Swine Slurry Application

AbstractSwine slurry is a common agricultural fertilizer in many countries. However, its long‐term use in large amounts can cause excess nutrient accumulation, alter soil compounds, and potentially influence critical microbial populations such as arbuscular mycorrhizal fungi, which have important roles in plant nutrition and soil sustainability. This work determined if arbuscular mycorrhizal status, external mycelium, and glomalin‐related soil protein content were affected by long‐term swine slurry application to different soil tillage systems. The experiment was conducted on a clayey oxisol, in southern Brazil. Swine slurry (0, 30, 60, 90, and 120 m3 ha−1 y−1) was applied for 15 years to conventional tillage and no tillage soil prior to the summer (soybean or maize) and winter (wheat or oats) crop seasons. Swine slurry decreased mycorrhizal root colonization, spore number, and total external mycelium. Swine slurry increased active external mycelium and both easily extractable and total glomalin‐related soil protein. No‐tillage soil had more glomalin‐related soil protein than conventional tillage soil. The most significant response variables were root colonization, easily extractable glomalin‐related soil protein, and total external arbuscular mycorrhizal mycelia. Long‐term application of swine slurry in this environment, even at high rates, did not adversely affect crop yield but did influence arbuscular mycorrhizae fungi and their products in the soil environment. Benefits of swine slurry application for crop nutrition must be weighed against potential adverse consequences for the size, activity, and benefits of the mycorrhizal community to subsequent annual crops. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Arbuscular mycorrhiza (AM) status of rehabilitation plants of mine wastes in South Africa and determination of AM fungal diversity by analysis of the small subunit rRNA gene sequences

The aim of this study was to assess the arbuscular mycorrhizal (AM) status of trees currently being used for phytoremediation of mining contaminated sites in South Africa, and to determine the AM fungal diversity of these sites. The trees, Tamarix usneoides, Searsia lancea and Searsia pendulina planted on waste sites associated with gold and uranium and zinc and platinum mining were assessed in late summer and the AM fungi were identified by molecular analysis of the small subunit rRNA gene sequences from spore DNA. All trees on all sites showed moderate to high mycorrhizal colonisation levels including those from wild populations of T. usneoides growing in uncontaminated sites. The AM fungi identified fell within the Claroideoglomus, Diversispora, Glomus, Acaulospora and Sclerocystis taxa and although their species diversity was relatively low there were distinct trends in their association with the three plant species sampled. The study represents a first report of the mycorrhizal status of T. usneoides and of the use of molecular techniques for the identification of AM fungi associated with mine wastes in South Africa. The results will assist in making decisions about the application of AM fungal inoculum in phytoremediation programmes for mine waste rehabilitation.

Arbuscular Mycorrhizal (AM) and Dark Septate Endophyte (DSE) Fungal Association in Lycophytes and Ferns of the Kolli Hills, Eastern Ghats, Southern India

We examined the extent and type of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in three lycophyte and 44 fern species collected from three different sites in the Kolli Hills, Eastern Ghats, southern India. Of the 47 plant taxa (belonging to 21 families and 33 genera) examined, 46 had AM fungal and 33 had DSE fungal associations. But, fungal structures were absent in the aquatic fern Azolla pinnata (Azollaceae). This is the first report of AM and DSE fungal status for 16 and 28 species, respectively. Among terrestrial lycophytes and ferns, 26 species had dual association of both AM and DSE fungi, whereas 11 species had only AM fungal association. Vittaria elongata from epiphytic habitats had dual association of AM and DSE fungi. Likewise, Cheilanthes tenuifolia (saxicolous or terrestrial), Cheilanthes opposita, Lepisorus nudus, Pyrrosia lanceolata (terrestrial or epiphytic), and Asplenium lanceolatum (saxicolous or epiphytic) examined from different sites or habitats also had dual association of AM and DSE fungi. Seventy two percent of the mycorrhizal lycophytes and ferns had intermediate-type AM and 15 percent had both Paris- and intermediate-types at different sites. Significant variations in AM fungal structures were evident in 16 ferns occurring in two or more sites. Nine AM fungal spore morphotypes belonging to Acaulospora, Funneliformis, Glomus, Gigaspora, and Sclerocystis were found to be associated with lycophytes and ferns.

Arbuscular mycorrhizal fungi: potential biocontrol agents against the damaging root hemiparasite Pedicularis kansuensis?

Spatial expansion of root hemiparasitic Pedicularis kansuensis in Bayanbulak Grassland of Xinjiang Uygur Autonomous Region (China) has caused great loss of herbage yield and has threatened the local livestock industry. Current management practices using manual eradication and chemical control have been proved problematic. Arbuscular mycorrhizal (AM) fungi have been suggested to be potential biocontrol agents against a number of plant pests, but experimental evidence is lacking against weedy P. kansuensis. In this study, we tested the hypothesis that inoculation with AM fungi will cause growth depression in P. kansuensis and reduce its damage to host plants. Based on the confirmation of AM status and host community of the hemiparasite in the field, a pot cultivation experiment was conducted to test the influence of an AM fungus (Glomus mosseae) on growth of P. kansuensis and the parasitized host (Elymus nutans). AM colonization was observed in roots of P. kansuensis, but the levels were much lower than those of its adjacent host species. A negative correlation between AM levels and the numbers of haustoria was detected for the field samples of the hemiparasite. Strong suppression of haustorium formation, a significant reduction in plant dry weight (DW), as well as marked reduction in the survival rate of P. kansuensis after inoculation with AM fungi was observed. In contrast, inoculation with G. mosseae increased root DW and whole plant DW of parasitized host plants. Our findings demonstrated significantly repressive effects of AM fungi on growth performance of P. kansuensis with and without the presence of a host. The potential of AM fungi as biocontrol agents against the damaging hemiparasite was confirmed.

Arbuscular mycorrhizal colonization in Asteraceae from white sand savannas, in Pinar del Río, Cuba

Asteraceae family shows a great diversity in Cuba and presents threatened taxons in high number. Pinar del Río has 19 threatened species belonging to this family and three of them are characteristic of a sandy (quartzitic) soil at the Reserva Florística Manejada San Ubaldo-Sabanalamar (Floristic Reserve San Ubaldo-Sabanalamar). The arbuscular mycorrhizal status and colonization rate in Aster grisebachii, Erigeron bellidiastroides, Erigeron cuneifolius, Pectis juniperinaand Sachsia polycephala (Asteraceae) from this Reserve was determined in October 2009 and April 2010, during hydrologic rainy and dry period, respectively. All species were mycotrophic in both periods with a high percentage of colonization rates, between 66 and 100% in rainy period and between 84 and 100% in dry period. Vesicles, arbuscules, spores, hyphal and arbuscular coils of arbuscular mycorrhizae were observed. Paris -type andArum -type morphologies (both) were observed indistinctly in all the species, and Intermediate type was observed only in Aster grisebachii andErigeron bellidiastroides, which could be a hint that these species are colonized by more than one fungal species, and therefore enhancing the relevance of fungal identity as a considerable character in the morphology association. Also, septate hyphae and microsclerotium of dark septate endophytes were identifyed inside the roots of all the species.

Investigation on arbuscular mycorrhizal alliances in some threatened medicinal herbs of Burdwan district, West Bengal, India

Perseverance of conventional herbal medicines is increasing gradually throughout the world. Considering the growing demand of ethnomedicinal plants in therapeutic treatments to our primary health care system and the role of vesicular arbuscular mycorrhizae (VAM) fungi for enhanced production of active secondary metabolites by the medicinal plants, the present work was undertaken to survey the arbuscular mycorrhizal status in some common medicinal herbs like, Abrus precatorius, Elephantopus scaber, Sida rhombifoliaand Clerodendrum indicum. As evidenced from Grid-line intersect method, all the plants under investigation were colonized by the vesicular arbuscular mycorrhizal fungi as both the vesicles and arbuscules were present in the roots. Arbuscular frequency was the highest in the roots of E. scaber (0.3 to 98.7), followed by A. precatorius (5.97 to 61.46) and lowest inC. indicum (0.1 to 31.7). Correspondingly, vesicular frequency was the highest in E. scaber(0 to 63.33) and lowest in C. indicum (31.83 to 40.2). It is apparent from the results that the extent of mycorrhizal colonization varied significantly with the seasonal variations throughout the year. Spore analysis from the rhizosphere soil sample exhibited a great deal of variation in their frequency and occurrence in different seasons of the year and also in their morphological features. The VAM/arbuscular mycorrhizae (AM) fungi observed in the present study mostly belong to the species group of Glomus. Key words: Vesicular arbuscular mycorrhizae (VAM), arbuscular mycorrhizae (AM),Glomus species, Acaulospora scrobiculata, Sclerocystis species, Abrus precatorius,Elephantopus scaber, Sida rhombifolia, Clerodendrum indicum.