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Direct Effects Of Soil Cadmium And Lead On Growth Of Arbuscular Mycorrhizal Fungi

Posted on:2006-10-01Degree:MasterType:Thesis
Country:ChinaCandidate:S B ZhangFull Text:PDF
GTID:2120360152492173Subject:Plant Nutrition
Abstract/Summary:PDF Full Text Request
Arbuscular mycorrhizas are obligate mutualistic associations and arbuscular mycorrhizal (AM) fungi cannot grow without suitable host plants. It is therefore difficult to harvest arbuscular mycorrhizal fungal mycelium. Previous studies have focused mainly on the influence of AM fungi on the physiology of the host plant and there are few published reports on the influence of the host plant and edaphic factors on the growth and metabolic activities of AM fungi. In the present study a compartment cultivation system was developed to study the direct effects of soil heavy metals on the growth of three AM fungi, Glomus mosseae, G. etunicatum and G. claroideum, under controlled conditions. Hyphal zones with different heavy metal concentrations were established in the same root compartment. The objectives were to establish and test the effectiveness of new methods to study the direct effects of environmental factors on AM fungi.The total external hyphal length of all three AM fungi was greatest at a soil Cd concentration of 5 mg/kg, indicating that a small addition of Cd to the soil stimulated the growth of the AM fungi compared with controls receiving no Cd. In contrast, Pb stimulated the growth of two of the AM fungi, G. claroideum and G. etunicatum, at a low soil Pb concentration of 100mg/kg. The growth of G. mosseae was unaffected by three elevated Pb concentrations in the soil (100, 500 and 1000 mg/kg). This suggests that G. mosseae and G. etunicatum were resistant to Pb toxicity.The experiments facilitated the harvesting of the extramatrical mycelium and the determination of the hyphal length of the three fungi in the hyphal zones under different heavy metal concentrations and were suitable for studies on the effects of the different heavy metals at various concentrations on the three AM fungi. The new method was therefore suitable for studying the effects of heavy metal on the AM fungi directly under the same plant growth conditions.
Keywords/Search Tags:Arbuscular mycorrhizal fungi, Cd, Pb, AM fungal growth, direct effects
PDF Full Text Request
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