Cluster Roots in Casuarinaceae: Role and Relationship to Soil Nutrient Factors

Rhizoeconomics: Carbon costs of phosphorus acquisition

“…This is especially the case for phosphorus. Functionally adaptive responses to low soil resource levels may include alterations in many of the phosphorus acquisition mechanisms that we have already discussed above, including, the formation of symbiotic relationships (Koide, 1991), uptake kinetics (Jackson and Caldwell, 1996), the production of root exudates (Diem et al, 2000;Neumann and Martinoia, 2002) changes in root localization (Bonser et al, 1996;Liao et al, 2001), and biomass allocation to different root types (Miller et al 2003), root morphology, such as the increase in production of root hairs (Bates and Lynch, 2000;Bates, 1998;Bates and Lynch, 1996) and aerenchyma (Drew et al, 2000;Fan et al, 2003). In some cases, the costs associated with plasticity responses can be significant (DeWitt et al, 1998;Alpert and Simms, 2002).…”

Structural development of vegetation on rehabilitated North Stradbroke Island: Above/belowground feedback may facilitate alternative ecological outcomes

“…This outcome reflects upon the rehabilitated sites achieving an increasingly stable and self-sustaining ecological status. However, it is suspected that the enrichment of soil-N pools (especially in the topsoil rather than in lower substrata) could alter the proportional distribution of soil nutrients to the benefit of species better adapted for nutrient scavenging (Diem et al 2000). While further experimental investigation would be needed to verify these facets on North Stradbroke Island, the predominance of N-fixing species (including Acacia spp.…”

“…By contrast, pioneer and/or facilitator species such as black sheoak often populate the adjacent fore-dunes, which have early-stage podzol soils (Lunt 1998b). Recalling that this latter species was directly seeded as part of the rehabilitation strategy (albeit at different seeding intensities depending on the period of rehabilitation), it is suspected that the loss of soil fertility and its reversion to an early podzol status would have facilitated initial growth conditions conducive to the species' opportunistic colonisation due to its general 'ruderal' adaptations to nutrient-poor conditions (Crowley 1984;Diem et al 2000). Conversely, such postdisturbance soil conditions could have been disadvantageous for the desired and relatively slowergrowing mixed-Eucalypts that are typically only sparsely distributed among the fore-dunes (Westman 1975).…”

Frankia Nodulation, Mycorrhization and Interactions Between Frankia and Mycorrhizal Fungi in Casuarina Plants

“…Some Casuarina species, including C. cunninghamiana, C. equisetifolia and C. glauca, even have the capacity to form cluster roots, which specialize in phosphorus (P) uptake from the soil (Diem 1996;Arahou and Diem 1997;Reddell et al 1997;Diem et al 2000;Zaïd et al 2003;Lambers et al 2006). In addition, a greater soil carbon (C) sequestration under C. equisetifolia than under Eucalyptus trees may provide important reforestation or afforestation strategies to compensate C emissions (Resh et al 2002), particularly in times of global environmental change.…”