Plant nutrient-acquisition strategies change with soil age.
Nitrogen (N) tends to limit plant productivity on young soils; phosphorus (P) becomes increasingly limiting in ancient soils because it gradually disappears through leaching and erosion. Plant traits that are regarded as adaptations to N- and P-limited conditions include mycorrhizas and cluster roots. Mycorrhizas 'scavenge' P from solution or 'mine' insoluble organic N. Cluster roots function in severely P-impoverished landscapes, 'mining' P fixed as insoluble inorganic phosphates. The 'scavenging' and 'mining' strategies of mycorrhizal species without and non-mycorrhizal species with cluster roots, respectively, allow functioning on soils that differ markedly in P availability. Based on recent advances in our understanding of these contrasting strategies of nutrient acquisition, we provide an explanation for the distribution of mycorrhizal species on less P-impoverished soils, and for why, globally, cluster-bearing species dominate on severely P-impoverished, ancient soils, where P sensitivity is relatively common.
Lambers
Hans
H
School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, WA 6009, Australia. hans.lambers@uwa.edu.au
Raven
John A
JA
Shaver
Gaius R
GR
Smith
Sally E
SE
D038821:Mycorrhizae / Q000502:physiology*; D009584:Nitrogen; D010758:Phosphorus; D012987:Soil; D013997:Time Factors
D012987:Soil; D010758:Phosphorus; D009584:Nitrogen