Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 1203-1217 |
| Journal | Plant, Cell and Environment |
| Volume | 28 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 2005 |
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Physiological changes in white lupin associated with variation in root-zone CO2 concentration and cluster-root P mobilization. / Cramer, Michael; Shane, Michael; Lambers, Hans.
In: Plant, Cell and Environment, Vol. 28, No. 10, 2005, p. 1203-1217.Research output: Contribution to journal › Article
TY - JOUR
T1 - Physiological changes in white lupin associated with variation in root-zone CO2 concentration and cluster-root P mobilization
AU - Cramer, Michael
AU - Shane, Michael
AU - Lambers, Hans
PY - 2005
Y1 - 2005
N2 - White lupin (Lupinus albus L.) mobilizes insoluble soil phosphorus through exudation of organic acids from 'cluster' roots. Organic acid synthesis requires anaplerotic carbon derived from dark CO2 fixation involving PEP-carboxylase. We tested the hypothesis that variation in root-zone CO2 concentration would influence organic acid synthesis and thus P mobilization. Root-zone CO2 concentrations and soil FePO4 concentrations supplied to sand-grown white lupin (cv. Kiev Mutant) were varied. More biomass accumulated in plants supplied with 360 mu L L-1 CO2 to the root-zone, compared with those aerated with either 100 or 6000 mu L L-1 CO2. Increased FePO4 in the sand resulted in greater leaf P concentrations, but root-zone [CO2] did not influence leaf P concentration. Suppression of cluster-root development in plants supplied with 100 mu L L-1 root-zone CO2 was correlated with increased leaf [P]. However, at both 360 and 6000 mu L L-1 CO2, cluster-root development was suppressed only at the highest leaf P concentration. Phloem sap [P] was significantly increased by greater [FePO4] in the sand, but was reduced with increased root-zone [CO2], and this may have triggered increased cluster-root initiation. Succinate was the major organic acid (carboxylate) in the phloem sap (minor components included malate, citrate, fumarate) and was increased at greater [FePO4], suggesting that this shoot-derived carboxylate might provide an important source of organic acids for root metabolism. Since cluster root development was inhibited by increasing concentrations of FePO4 in the sand, it is possible that succinate was utilized for the functioning of the root-nodules.
AB - White lupin (Lupinus albus L.) mobilizes insoluble soil phosphorus through exudation of organic acids from 'cluster' roots. Organic acid synthesis requires anaplerotic carbon derived from dark CO2 fixation involving PEP-carboxylase. We tested the hypothesis that variation in root-zone CO2 concentration would influence organic acid synthesis and thus P mobilization. Root-zone CO2 concentrations and soil FePO4 concentrations supplied to sand-grown white lupin (cv. Kiev Mutant) were varied. More biomass accumulated in plants supplied with 360 mu L L-1 CO2 to the root-zone, compared with those aerated with either 100 or 6000 mu L L-1 CO2. Increased FePO4 in the sand resulted in greater leaf P concentrations, but root-zone [CO2] did not influence leaf P concentration. Suppression of cluster-root development in plants supplied with 100 mu L L-1 root-zone CO2 was correlated with increased leaf [P]. However, at both 360 and 6000 mu L L-1 CO2, cluster-root development was suppressed only at the highest leaf P concentration. Phloem sap [P] was significantly increased by greater [FePO4] in the sand, but was reduced with increased root-zone [CO2], and this may have triggered increased cluster-root initiation. Succinate was the major organic acid (carboxylate) in the phloem sap (minor components included malate, citrate, fumarate) and was increased at greater [FePO4], suggesting that this shoot-derived carboxylate might provide an important source of organic acids for root metabolism. Since cluster root development was inhibited by increasing concentrations of FePO4 in the sand, it is possible that succinate was utilized for the functioning of the root-nodules.
U2 - 10.1111/j.1365-3040.2005.01358.x
DO - 10.1111/j.1365-3040.2005.01358.x
M3 - Article
VL - 28
SP - 1203
EP - 1217
JO - Plant, Cell and Environment.
JF - Plant, Cell and Environment.
SN - 0140-7791
IS - 10
ER -