TY - JOUR
T1 - Arid-zone Acacia species can access poorly soluble iron phosphate but show limited growth response
AU - He, H.
AU - Bleby, Timothy
AU - Veneklaas, Erik
AU - Lambers, Hans
PY - 2012/9/1
Y1 - 2012/9/1
N2 - Background and aims
Phosphorus (P) is a commonly limiting nutrient for plant growth in natural environments. Many legumes capable of N2-fixation require more P than non-legumes do. Some legume crops can use sparingly soluble forms of P such as iron phosphate much better than other species, but reports on the ability of woody legumes to access iron phosphate are rare.
Methods
Plants of four Acacia species (Acacia stipuligera F. Muell., A. ancistrocarpa Maiden & Blakely, A. stellaticeps Kodela, Tindale & D. Keith and A. robeorum Maslin), native to the Great Sandy Desert in north-western Australia, were grown in a glasshouse in river sand with different levels of iron phosphate, between 0 and 16 μg Pg 1 sand. Plant growth, tissue P concentrations, and pH and carboxylates in the rhizosphere were measured.
Results
Growth of A. stipuligera and A. ancistrocarpa was not responsive to increased P supply; in contrast, A. stellaticeps and A. robeorum produced significantly more root and shoot dry mass at 8 and 16 μg P g 1 sand than at 0 μg P g 1 sand; differences in root mass ratio were significant between species but not between P treatments. A. robeorum was the only species colonised by mycorrhizal fungi, and the colonisation percentage decreased with increasing P supply. In all species, P-uptake rates and tissue P concentrations were significantly higher at greater P supply. Rhizosphere pH and the amount of carboxylates in the rhizosphere decreased with increasing P supply.
Conclusions
Net P uptake increased with increasing P supply, showing that the present Acacia species can access P from iron phosphate. However, due to their inherently slow growth rate, enhanced P supply did not increase growth of two of the four studied species. The ability of the Acacia species to access P from iron phosphate is presumably related with carboxylate exudation and rhizosphere acidification.
AB - Background and aims
Phosphorus (P) is a commonly limiting nutrient for plant growth in natural environments. Many legumes capable of N2-fixation require more P than non-legumes do. Some legume crops can use sparingly soluble forms of P such as iron phosphate much better than other species, but reports on the ability of woody legumes to access iron phosphate are rare.
Methods
Plants of four Acacia species (Acacia stipuligera F. Muell., A. ancistrocarpa Maiden & Blakely, A. stellaticeps Kodela, Tindale & D. Keith and A. robeorum Maslin), native to the Great Sandy Desert in north-western Australia, were grown in a glasshouse in river sand with different levels of iron phosphate, between 0 and 16 μg Pg 1 sand. Plant growth, tissue P concentrations, and pH and carboxylates in the rhizosphere were measured.
Results
Growth of A. stipuligera and A. ancistrocarpa was not responsive to increased P supply; in contrast, A. stellaticeps and A. robeorum produced significantly more root and shoot dry mass at 8 and 16 μg P g 1 sand than at 0 μg P g 1 sand; differences in root mass ratio were significant between species but not between P treatments. A. robeorum was the only species colonised by mycorrhizal fungi, and the colonisation percentage decreased with increasing P supply. In all species, P-uptake rates and tissue P concentrations were significantly higher at greater P supply. Rhizosphere pH and the amount of carboxylates in the rhizosphere decreased with increasing P supply.
Conclusions
Net P uptake increased with increasing P supply, showing that the present Acacia species can access P from iron phosphate. However, due to their inherently slow growth rate, enhanced P supply did not increase growth of two of the four studied species. The ability of the Acacia species to access P from iron phosphate is presumably related with carboxylate exudation and rhizosphere acidification.
U2 - 10.1007/s11104-011-1103-5
DO - 10.1007/s11104-011-1103-5
M3 - Article
VL - 358
SP - 119
EP - 130
JO - Plant and Soil: An International Journal on Plant-Soil Relationships
JF - Plant and Soil: An International Journal on Plant-Soil Relationships
SN - 0032-079X
IS - 1-2
ER -