Academic
Publications
Mycorrhizal fungi enhance accumulation and tolerance of chromium in sunflower (Helianthus annuus)

Mycorrhizal fungi enhance accumulation and tolerance of chromium in sunflower (Helianthus annuus),Fred T. Davies,Jeffrey D. Puryear,Ronald J. Newton,J

Mycorrhizal fungi enhance accumulation and tolerance of chromium in sunflower (Helianthus annuus)   (Citations: 42)
BibTex | RIS | RefWorks Download
Summary Chromium (Cr) is a heavy metal risk to human health, and a contaminant found in agricultural soils and industrial sites. Phytoremediation, which relies on phytoextraction of Cr with biological organ- isms, is an important alternative to costly physical and chemical methods of treating contaminated sites. The ability of the arbuscular mycorrhizal fungus (AM), Glomus intraradices, to enhance Cr uptake and plant tolerance was tested on the growth and gas exchange of sunflower (Helianthus annuus L.). Mycorrhizal-colonized (AM) and non-inoculated (Non-AM) sunflower plants were sub- jected to two Cr species (trivalent cation (Cr3 +) {Cr(III)}, and divalent dichromate anion (Cr2O7-) {Cr(VI)}). Both Cr species depressed plant growth, decreased net photosynthesis (A) and increased the vapor pressure difference; however, Cr(VI) was more toxic. Chromium accumulation was greatest in roots, intermediate in stems and leaves, and lowest in flowers. Greater Cr accumulation occurred with Cr(VI) than Cr(III). AM enhanced the ability of sunflower plants to tolerate and hyperaccumu- late Cr. At higher Cr levels greater mycorrhizal dependency occurred, as indicated by proportionally greater growth, higher A and reduced visual symptoms of stress, compared to Non-AM plants. AM plants had greater Cr-accumulating ability than Non-AM plants at the highest concentrations of Cr(III) and Cr(VI), as indicated by the greater Cr phytoextraction coefficient. Mycorrhizal colonization (arbuscule, vesicle, and hyphae formation) was more adversely affected by Cr(VI) than Cr(III), how- ever high levels of colonization still occurred at even the most toxic levels. Arbuscules, which play an important role in mineral ion exchange in root cortical cells, had the greatest sensitivity to Cr toxicity. Higher levels of both Cr species reduced leaf tissue phosphorus (P). While tissue P was higher in AM plants at the highest Cr(III) level, tissue P did not account for mycorrhizal benefits observed with Cr(VI) plants.
Published in 2001.
Cumulative Annual
View Publication
The following links allow you to view full publications. These links are maintained by other sources not affiliated with Microsoft Academic Search.
Sort by: