Effect of Copper on Glomalin Production by Two Glomeral Species in Symbiosis with Corn

Document Type : Research Paper

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Abstract

   Glomalin is a specific glycoprotein that is produced by a fungi belonging to the order Glomerales in phylum Glomeromycota. Noting the widespread symbiotic relation of these fungi with a large number of plants, considerable amounts of glomalin are entered into the soil ecosystems, annually. Heavy metals can influence the both symbionts physiology and hence glomalin production by the fungi. In this study, the effects of Cu levels were investigated on mycorrhizal establishment in corn plants inoculated by either Glomus mosseae or  G. intraradices  as well as glomalin production by the system. Copper levels of 0, 250 and 500 mg Cu.  kg-1 soil (as CuSO4.5H2O) were applied to the pots before plant culture. Non-mycorrhizal treatment was left un-inoculated as control. Easily extractable glomalin (EEG) and total glomalin (TG) were determined by the Bradford method after extraction from soil. With increasing Cu concentration in soil, shoot and root fresh and dry weights, P and K concentrations in shoot and root, root colonization, EEG and TG decreased and proline concentration in leaves, Cu concentration in shoot and root increased.  The results showed that, glomalin levels in fungal treatments significantly increased compared to the non-mycorrhizal control. The results also showed a positive correlation between the measured glomalin and the percent of root colonization.

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