Table 2.

Al³⁺-activated release of organic acids from roots of woody plants.

Plant species	Al3+-activated organic acids	Reference
Non-mycorrhizal roots; coniferous trees
Cryptomeria japonica	Citrate, oxalate	Hirano et al. (2012)
Picea abies	Oxalate	Heim et al. (2001)
Picea abies	–	Eldhuset et al. (2007)
Pinus sylvestris	Oxalate	Ahonen-Jonnarth et al. (2000)
Pinus thunbergii	Citrate, oxalate	Hirano et al. (2012)
Non-mycorrhizal roots; broad-leaved trees (deciduous)
Populus tremula	Citrate, oxalate	Qin et al. (2007)
Populus tremuloides	Citrate, malate, oxalate, succinate	Naik et al. (2009)
Populus trichocarpa	Citrate, malate, oxalate, succinate	Naik et al. (2009)
Non-mycorrhizal roots; broad-leaved trees and shrubs (evergreen)
Acacia auriculiformis	Citrate, oxalate	Nguyen et al. (2003)
Camellia sinensis	Oxalate	Morita et al. (2011)
Camellia sinensis	–	Ishikawa et al. (2000)
Cinnamomum camphora	Citrate	Osawa et al. (2011)
Citrus grandis	Citrate, malate	Yang et al. (2011)
Citrus junos	Citrate	Deng et al. (2009)
Citrus sinensis	Citrate, malate	Yang et al. (2011)
Eucalyptus camaldulensis	Citrate, oxalate	Tahara et al. (2008)
Eucalyptus camaldulensis	Citrate, oxalate	Nguyen et al. (2003)
Eucalyptus cloeziana	Citrate	Silva et al. (2004)
Eucalyptus dunnii	Citrate, malate, oxalate	Silva et al. (2004)
Eucalyptus globulus	Citrate, malate	Silva et al. (2004)
Eucalyptus grandis	Citrate	Silva et al. (2004)
Eucalyptus saligna	Citrate	Silva et al. (2004)
Eucalyptus urophylla	Citrate, malate, oxalate	Silva et al. (2004)
Melaleuca bracteata	Citrate	Tahara et al. (2008)
Melaleuca cajuputi	Citrate, malate	Tahara et al. (2008)
Melaleuca cajuputi	Citrate, oxalate	Nguyen et al. (2003)
Melaleuca leucadendra	Citrate	Nguyen et al. (2003)
Mycorrhizal roots
Picea abies	Succinate	Heim et al. (2003)
Picea abies	–	Eldhuset et al. (2007)
Pinus densiflora	Citrate	Tahara et al. (2005)
Pinus sylvestris	Oxalate	Ahonen-Jonnarth et al. (2000)

The references are divided into studies dealing either with non-mycorrhizal roots or with mycorrhizal roots.