Selection of Ectomycorrhizal Fungi and Tree Species for Rehabilitation of Cu Mine Tailings in the Philippines


Nelly S Aggangan, Brian James S Aggangan
Vol 15 No 1 (2012), pp. 59-71

 

Abstract:

 

Abandoned mine tailings sites are prevalent throughout the world and generally remain barren for ten to hundred years. This is due to the presence of heavy metals such as copper (Cu), an essential micronutrient but toxic to plants and microorganisms at high concentration. Laboratory and screenhouse experiments were conducted to screen ectomycorrhizal (ECM) fungi that increase Cu tolerance of Eucalyptus and Acacia seedlings for the rehabilitation of Cu mine tailings in the Philippines and to determine which tree species can survive better in soil with high Cu concentration. Irrespective of Cu levels, Pisolithus 23-01 yielded the highest mycelial growth and was unaffected by Cu addition up to 750 μM. Likewise, growth of Pisolithus H6394, Scleroderma sp. and Astreus sp. was not affected by Cu but grew slower than Pisolithus 23-01. Under nursery conditions, E. urophylla and A. aulacocarpa seedlings inoculated with Pisolithus, Scleroderma and Astraeus and planted in garden soil amended with 250, 500 and 750 μM Cu and no Cu, grew better than the non-mycorrhizal ones. Root colonization (10 to 30%) by ECM fungi was not affected by Cu. Seedlings inoculated with Pisolithus (23-01 and H6394) and Scleroderma comparably promoted greater height increment, stem diameter and dry weight than the uninoculated ones. Pisolithus H6394 consistently gave the highest seedling growth, dry weight, P and Cu uptake of E. urophylla irrespective of Cu level. Phosphorus uptake was inversely related with Cu uptake. The addition of 750 μM Cu reduced the growth of non-mycorrhizal seedlings and those inoculated with Astraeus but did not affect the Pisolithus and Scleroderma inoculated plants. In Cu mine tailing soil, A. aulacocarpa survived and grew better than E. urophylla, E. deglupta, and A. mangium. Pisolithus 23-01 promoted the best growth of both Acacia and Eucalyptus species. ECM fungi, specifi cally Pisolithus can enhance Cu tolerance of Acacia aulacocarpa and Eucalyptus urophylla and can be used for phytoremediation of Cu mine tailings in the Philippines.

 

Keywords: heavy metals, ectomycorrhizal fungi, Eucalyptus, Acacia, mine tailings


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