Role of arbuscular mycorrhizal symbiosis in phosphorus-uptake efficiency and aluminium tolerance in barley growing in acid soils

2015 ◽  
Vol 66 (7) ◽  
pp. 696 ◽  
Author(s):  
Alex Seguel ◽  
José Miguel Barea ◽  
Pablo Cornejo ◽  
Fernando Borie

Arbuscular mycorrhizal fungi (AMF) play an important role in protecting plant growth against such stresses as phytotoxic aluminium (Al) in soil. To understand some of the AMF interactions that relate to amelioration of Al phytotoxicity and phosphorus (P)-uptake efficiency in barley (Hordeum vulgare L.), this study examined the effect of soil Al levels and mycorrhizal symbiosis on plant response, including root colonisation, AMF propagules and glomalin production. A greenhouse experiment was conducted using two native barley cultivars, Sebastián and Aurora, grown in an acidic soil at two Al-saturation levels (80% Al-sat, unlimed soil; 7% Al-sat, limed soil) with and without AMF propagules. Root dry weight, total and colonised root lengths, and root P and Al contents were determined at 60 and 150 days after sowing. AMF spore density, total hyphal length, glomalin-related soil protein (GRSP) and Al bound to GRSP (Al-GRSP) were analysed at final harvest. AM root colonisation was not inhibited in limed soil, mycorrhizal propagule numbers increased at high Al levels, and Al-GRSP ranged from 5.6% to 8.3% of the total GRSP weight. These values also increased in unlimed soil, particularly those associated with cv. Aurora. Root Al concentration correlated inversely with AMF spores (r = –0.85, P < 0.001) and Al-GRSP (r = –0.72, P < 0.01), but only in plants growing in limed soil. Conversely, the AMF treatments in which Al was present showed a greater relationship between total root length and both root Al (r = –0.72, P < 0.01) and root P (r = 0.66, P < 0.01) concentrations. Sebastián showed a greater response to lime, whereas Aurora responded better to mycorrhizal presence. The relative growth rate of roots, P uptake efficiency and mycorrhizal parameters such as root colonisation, spores, hyphae and GRSP showed Aurora to be more Al-tolerant than Sebastián. In conclusion, the greater rate of increase of AM propagules, GRSP and Al-GRSP associated with cv. Aurora supports the hypothesis that AMF play an important role in the Al-tolerance capacity and P-uptake efficiency of H. vulgare growing in soils with high Al levels.

2021 ◽  
Author(s):  
Mark Tibbett ◽  
Matthew I Daws ◽  
Megan H Ryan

Many plant species from regions with ancient, highly-weathered nutrient-depleted soils have specialised adaptations for acquiring P and are sensitive to excess P-supply. Mycorrhizal associations may regulate P-uptake at high external P-concentrations, potentially reducing P-toxicity. We predicted that excess P-application will negatively impact species from the nutrient-depleted jarrah forest of Western Australia and that mycorrhizal inoculation will reduce P-toxicity by regulating P-uptake. For seedlings of the N2-fixing legume Acacia celastrifolia and the tree species Eucalyptus marginata, we measured growth at P-concentrations of 0 to 90 mg kg-1 soil and in relation to inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis. Non-inoculated A. celastrifolia maintained leaf P-concentrations at <2 mg g-1 dry mass (DM) across the range of external P-concentrations. However, for non-inoculated E. marginata, as external P-concentrations increased leaf P also increased, reaching >9 mg g-1 DM at 30 mg P kg-1 soil. A. celastrifolia DM increased with increasing external P-concentrations, while E. marginata DM was maximal at 15 mg P kg-1 soil, declining at higher external P concentrations. Neither DM nor leaf P of A. celastrifolia were affected by inoculation with AMF. For E. marginata, even at 90 mg P kg-1 soil, inoculation with AMF resulted in leaf P remaining <1 mg g-1 DM, and DM being maintained. These data strengthen the evidence base that AMF may not only facilitate P-uptake at low external P-concentrations, but are also important for moderating P-uptake at elevated external P-concentrations and maintaining plant P concentrations within a relatively narrow concentration range.


2019 ◽  
Vol 69 (13) ◽  
pp. 1309-1327 ◽  
Author(s):  
Catarina Drumonde Melo ◽  
Christopher Walker ◽  
Claudia Krüger ◽  
Paulo A.V. Borges ◽  
Sara Luna ◽  
...  

Abstract Purpose Arbuscular mycorrhizal fungi (AMF) play important key roles in the soil ecosystems as they link plants to the root-inaccessible part of soil. The aims of this study were to investigate which environmental factors influence the spatial and temporal structuring of AMF communities associated to Picconia azorica in two Azorean islands (Terceira and São Miguel islands), and investigate the seasonal variation in AMF communities between the two islands. Methods Communities of AMF associated with P. azorica in native forest of two Azorean islands (Terceira and São Miguel) were characterised by spore morphology or molecular analysis. Results Forty-five AMF spore morphotypes were detected from the four fragments of P. azorica forest representing nine families of AMF. Acaulosporaceae (14) and Glomeraceae (9) were the most abundant families. AMF density and root colonisation varied significantly between islands and sampling sites. Root colonisation and spore density exhibited temporal patterns, which peaked in spring and were higher in Terceira than in São Miguel. The relative contribution of environmental factors showed that factors such as elevation, relative air humidity, soil pH, and soil available P, K, and Mg influenced AMF spore production and root colonisation. Conclusion Different sporulation patterns exhibited by the members of the commonest families suggested different life strategies. Adaptation to a particular climatic and soil condition and host phenology may explain seasonal differences in sporulation patterns. Cohorts of AMF associated to P. azorica are shaped by regional processes including environmental filters such as soil properties and natural disturbance.


1992 ◽  
Vol 28 (4) ◽  
pp. 433-442 ◽  
Author(s):  
Edwin Weber ◽  
Eckhard George ◽  
Douglas P. Beck ◽  
Mohan C. Saxena ◽  
Horst Marschner

SUMMARYInoculation with vesicular-arbuscular mycorrhizal fungi (VAMF) improved growth of chick-pea (Cicer arielinum L.) and doubled phosphorus (P) uptake at low and intermediate levels of P fertilization in a pot experiment on sterilized low-P calcareous soil. In field experiments at Tel Hadya, northern Syria, growth, shoot P concentration and seed yield of spring-sown chickpea remained unaffected by inoculation with VAMF or by P fertilization. The mycorrhizal infection of chickpea was high (approximately 75% of root length mycorrhizal at the flowering stage) irrespective of inoculation with VAMF or P fertilization and may ensure efficient P uptake under field conditions.


2013 ◽  
Vol 281 ◽  
pp. 664-669
Author(s):  
En Wu ◽  
Guo Rong Xin ◽  
Kazuo Sugawara

With the aggravation of volcanic ash Andosol acidification, artificial forage grass Dactylis glomerata L. gradual degradation, replaced by weed plant Anthoxanthum odoratum L., but the mechanism is unclear. In order to reveal the mechanism, this study used Andosol soil as matrix, explored the effects of arbuscular mycorrhizal fungi on D. glomerata and A. odoratum at different pH gradients in acidic Andosol by glasshouse experiment. The results show that the mycorrhizal colonization of D. glomerata strongly affected by soil pH, but the A. odoratum was not yet. The mycorrhizal symbiosis led to a positive effect on growth and P uptake of D. glomerata and A. odoratum. Consider to invasion and expansion of A. odoratum in severity acidic pasture is origin of this specificity on arbuscular mycorrhizal symbiosis in acidic soil other than D. glomerata.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10173
Author(s):  
Luis G. Sarmiento-López ◽  
Melina López-Meyer ◽  
Gabriela Sepúlveda-Jiménez ◽  
Luis Cárdenas ◽  
Mario Rodríguez-Monroy

In plants, phosphorus (P) uptake occurs via arbuscular mycorrhizal (AM) symbiosis and through plant roots. The phosphate concentration is known to affect colonization by AM fungi, and the effect depends on the plant species. Stevia rebaudiana plants are valuable sources of sweetener compounds called steviol glycosides (SGs), and the principal components of SGs are stevioside and rebaudioside A. However, a detailed analysis describing the effect of the phosphate concentration on the colonization of AM fungi in the roots and the relationship of these factors to the accumulation of SGs and photochemical performance has not been performed; such an analysis was the aim of this study. The results indicated that low phosphate concentrations (20 and 200 µM KH2PO4) induced a high percentage of colonization by Rhizophagus irregularis in the roots of S. rebaudiana, while high phosphate concentrations (500 and 1,000 µM KH2PO4) reduced colonization. The morphology of the colonization structure is a typical Arum-type mycorrhiza, and a mycorrhiza-specific phosphate transporter was identified. Colonization with low phosphate concentrations improved plant growth, chlorophyll and carotenoid concentration, and photochemical performance. The transcription of the genes that encode kaurene oxidase and glucosyltransferase (UGT74G1) was upregulated in colonized plants at 200 µM KH2PO4, which was consistent with the observed patterns of stevioside accumulation. In contrast, at 200 µM KH2PO4, the transcription of UGT76G1 and the accumulation of rebaudioside A were higher in noncolonized plants than in colonized plants. These results indicate that a low phosphate concentration improves mycorrhizal colonization and modulates the stevioside and rebaudioside A concentration by regulating the transcription of the genes that encode kaurene oxidase and glucosyltransferases, which are involved in stevioside and rebaudioside A synthesis in S. rebaudiana.


Author(s):  
Poonam Jaiswal ◽  
Suresh Singh Rajpurohit

Mycorrhizal symbiosis occurs between arbuscular mycorrhizal fungi and most of the vascular plants and is a highly evolved mutually beneficial relationship occurring within the rhizosphere of the vascular plants. The host plants are directly conferred benefits to the growth and development due to this symbiotic association. Their function ranges from stress alleviation to bioremediation in polluted soils besides their importance in the restoration of degraded wastelands. In this investigation colonization percentage and spore density of VAM fungi were studied in industrial waste dump sites and soil having natural vegetation. Industrial waste dump sites are characteristically dominated by Glomus. Mycorrhizal association and spore formation potential of AMF was significantly lowered in soil disturbed due to industrial waste dumping.


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