Response of Three Arbuscular Mycorrhizal Fungi to Simulated Acid Rain and Aluminium Stress

Simulated acid rain (SAR) combined with higher concentration of aluminium (SAR+Al) influenced the ecophysiology of three arbuscular mycorrhizal fungi (AMF) in both the germination and symbiotic phases of their life cycle. Acaulospora tuberculata, an isolate from the soil with low pH, exhibited a higher tolerance to environmental stress as compared to Glomus mosseae and G. fistulosum. This higher tolerance may be related to the edaphic conditions of soil of the isolate origin. The histochemical staining of the alkaline phosphatase and NADH-diaphorase activities in the extraradical mycelium (ERM) of the AMF proved to be more sensitive indication of negative effects of the SAR or SAR+Al stress compared to commonly measured parameters of the AMF such as mycorrhizal colonisation or growth of the ERM.