Arbuscular mycorrhizal fungi might alleviate aluminium toxicity in banana plants

Abstract

Some mycorrhizal plants exhibit greater resistance than nonmycorrhizal plants to aluminium toxicity. This has not yet been shown for banana despite its importance as a cash and food crop in tropical regions, although bananas are sensitive to aluminium stress. We studied the effects of the arbuscular mycorrhizal fungus Glomus intraradices in alleviating aluminium toxicity in the banana cultivar Grande Naine grown in a continuous-nutrient-flow cultivation system using dilute solution. The micropropagated plants, some of which were inoculated with arbuscular mycorrhizal fungus, were grown for 40 d in pots filled with sand, and continuously irrigated with a nutrient solution containing up to 180 µM of aluminium. Water and nutrient uptake were measured once a week for 24 h, and root arbuscular mycorrhizal fungal colonization, biomass production, and mineral content of roots and shoots were measured at harvest. The root arbuscular mycorrhizal fungal colonization was large, and not significantly influenced by aluminium treatment. The effects of aluminium on both mycorrhizal and nonmycorrhizal plants were : decrease in biomass production, water and nutrient uptake, and magnesium content of roots and shoots ; greater aluminium content in roots than in shoots ; and increase in potassium and phosphorus content, particularly in roots. A significant positive effect of arbuscular mycorrhizal fungi on plant growth was observed with aluminium treatment, and was most pronounced at the highest concentration. The benefits, compared with nonmycorrhizal plants, included : increase in shoot dry weight, uptake of water and of most nutrients, and in calcium, magnesium and phosphorus content, particularly in roots ; decrease in aluminium content in root and shoot ; and delay in the appearance of aluminium-induced leaf symptoms. These results indicate that arbuscular mycorrhizal fungi could be effective in alleviating aluminium toxicity to banana plants.

The European project MYRRH : Use of mycorrhizal fungi for the phytostabilisation of radio-contaminated environments

“…Accumulation/sequestration in fungal structures has been demonstrated earlier [8,14] and hypothesised for toxic elements such as aluminium [15]. Fixation on extramatrical binding sites, sequestration within extraradical mycelium or intraradical structures i.e.…”

Responses of soil microbial and nematode communities to aluminum toxicity in vegetated oil-shale-waste lands

“…In addition, the residual Al concentrations and total Al concentrations showed a significant decrease after planting S. cumini plantation onto the shale dump, which suggests that S. cumini tree species is effective for amending the Al contaminated soils. AM fungi have been reported to be effective in alleviating Al toxicity to plants by enhancing the nutrient and water acquisition in metal-contaminated soils although it may not degrade the metal toxicity directly (Clark 1997;Meharg and Cairney 2000;Rufyikiri et al 2000;Wu 2008). Planting trees associated with mycorrhizal fungi seems to be a robust and promising bioremediation strategy for many polluted soil sites (Banitz et al 2011).…”

“…The metal of greatest concentration in oil shale waste is Al ([1,000 mg kg -1 ) with small amounts of As, Cr, Cd, Pb, Ni, Mn, Zn and Cu (Xia et al 2004). Aluminum toxicity is a major growth-limiting factor for crop cultivation in acid soils and many studies have demonstrated the suppressive effects in different plant species of soluble Al on root and shoot growth and water and nutrient uptake (Kochian 1995;Clark 1997;Rufyikiri et al 2000). In addition, soil microorganisms or nematodes were more sensitive than roots as indicators of subtle chemical changes in soil or water solution with Al toxicity (Williams and Dusenbery 1990;Joner et al 2005).…”

Understanding Root Uptake of Nutrients, Toxic and Polluting Elements in Hydroponic Culture

“…The banana plant is a model case study since this plant is very sensitive to Al stress (Rufyikiri 2000a(Rufyikiri , 2000b and it exhibits very large K requirements and growth rate (Lahav, 1995), as well as selective root uptake of NH 4 . Thus banana plant has a high potential for acidifying its own rhizosphere, and thereby in solubilizing toxic forms of Al.…”

“…In monoxenic cultivation, Rufyikiri et al (2000a) show that arbuscular mycorrhizal (AM) fungi (Glomus intraradices) can be effective in alleviating the aluminium toxicity to banana plants. In that study, both banana plants and AM fungi grew very well in sand under continuous nutrient flow.…”