Abstract
Plant species and cultivars elicit a diverse array of sophisticated metabolic and developmental strategies to enhance phosphorus (P) solublization and acquisition from P-deficient rooting media. Scavenging of phosphate (Pi) from extracellular sparingly soluble P sources may be aided by organic acids (OAs) exudation and root-mediated pH changes under a P-stress environment. Root exudates were collected to quantify short-term (4 h, 8 h) carboxylate exudation using hydroponically grown Brassica cultivars. Malic and citric acids were the dominant OAs and efficient cultivars exuded 2-3-fold more OAs than inefficient cultivars under P-deficient conditions. However, the exudation rate of both resistant and sensitive cultivars decreased with time. Experiments in nutrient solution were conducted to evaluate growth responses and the P solublization and acquisition ability of six genetically diverse Brassica cultivars. Pre-germinated seedlings were grown in nutrient solution containing ammonium di-hydrogen phosphate (AP), tri-calcium phosphate (TCP) and rock phosphate (RP) (TCP at 0.2 g L -1 and RP at 2 g L -1, in a bid to maintain deficiently buffered solution-P concentration) as different P sources. The cultivars exhibited substantial growth differences (P <0.001) in terms of biomass accumulation, P acquisition and P utilization efficiency (PUE). Biomass production correlated significantly (P <0.01) with their shoot P uptake and PUE at both P sources, indicating that cultivars efficient in P solublization accumulated more biomass. Higher P uptake by all cultivars was significantly related to the drop in root medium pH, which was presumably owing to H + efflux from the roots supplied with TCP and RP. Higher shoot dry matter of the cultivars at TCP was related to better P acquisition ability, which in turn was related to higher Ca uptake. Thus, cultivars with efficient Ca accumulation ability can acquire higher amounts of P from P-deficient soils and can adapt well to such low-P soil conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 623-633 |
| Number of pages | 11 |
| Journal | Soil Science and Plant Nutrition |
| Volume | 52 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Oct 2006 |
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Keywords
- Brassica cultivars
- Citrate
- Malate
- P solublization
- P uptake
- PUE
- RP
- TCP
ASJC Scopus subject areas
- Soil Science
- Agronomy and Crop Science
Cite this
Phosphorus starvation induced root-mediated pH changes in solublization and acquisition of sparingly soluble P sources and organic acids exudation by Brassica cultivars. / Shahbaz, Akhtar M.; Oki, Yoko; Adachi, Tadashi; Murata, Yoshiyuki; Khan, Md Harunar Rashid.
In: Soil Science and Plant Nutrition, Vol. 52, No. 5, 10.2006, p. 623-633.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phosphorus starvation induced root-mediated pH changes in solublization and acquisition of sparingly soluble P sources and organic acids exudation by Brassica cultivars
AU - Shahbaz, Akhtar M.
AU - Oki, Yoko
AU - Adachi, Tadashi
AU - Murata, Yoshiyuki
AU - Khan, Md Harunar Rashid
PY - 2006/10
Y1 - 2006/10
N2 - Plant species and cultivars elicit a diverse array of sophisticated metabolic and developmental strategies to enhance phosphorus (P) solublization and acquisition from P-deficient rooting media. Scavenging of phosphate (Pi) from extracellular sparingly soluble P sources may be aided by organic acids (OAs) exudation and root-mediated pH changes under a P-stress environment. Root exudates were collected to quantify short-term (4 h, 8 h) carboxylate exudation using hydroponically grown Brassica cultivars. Malic and citric acids were the dominant OAs and efficient cultivars exuded 2-3-fold more OAs than inefficient cultivars under P-deficient conditions. However, the exudation rate of both resistant and sensitive cultivars decreased with time. Experiments in nutrient solution were conducted to evaluate growth responses and the P solublization and acquisition ability of six genetically diverse Brassica cultivars. Pre-germinated seedlings were grown in nutrient solution containing ammonium di-hydrogen phosphate (AP), tri-calcium phosphate (TCP) and rock phosphate (RP) (TCP at 0.2 g L -1 and RP at 2 g L -1, in a bid to maintain deficiently buffered solution-P concentration) as different P sources. The cultivars exhibited substantial growth differences (P <0.001) in terms of biomass accumulation, P acquisition and P utilization efficiency (PUE). Biomass production correlated significantly (P <0.01) with their shoot P uptake and PUE at both P sources, indicating that cultivars efficient in P solublization accumulated more biomass. Higher P uptake by all cultivars was significantly related to the drop in root medium pH, which was presumably owing to H + efflux from the roots supplied with TCP and RP. Higher shoot dry matter of the cultivars at TCP was related to better P acquisition ability, which in turn was related to higher Ca uptake. Thus, cultivars with efficient Ca accumulation ability can acquire higher amounts of P from P-deficient soils and can adapt well to such low-P soil conditions.
AB - Plant species and cultivars elicit a diverse array of sophisticated metabolic and developmental strategies to enhance phosphorus (P) solublization and acquisition from P-deficient rooting media. Scavenging of phosphate (Pi) from extracellular sparingly soluble P sources may be aided by organic acids (OAs) exudation and root-mediated pH changes under a P-stress environment. Root exudates were collected to quantify short-term (4 h, 8 h) carboxylate exudation using hydroponically grown Brassica cultivars. Malic and citric acids were the dominant OAs and efficient cultivars exuded 2-3-fold more OAs than inefficient cultivars under P-deficient conditions. However, the exudation rate of both resistant and sensitive cultivars decreased with time. Experiments in nutrient solution were conducted to evaluate growth responses and the P solublization and acquisition ability of six genetically diverse Brassica cultivars. Pre-germinated seedlings were grown in nutrient solution containing ammonium di-hydrogen phosphate (AP), tri-calcium phosphate (TCP) and rock phosphate (RP) (TCP at 0.2 g L -1 and RP at 2 g L -1, in a bid to maintain deficiently buffered solution-P concentration) as different P sources. The cultivars exhibited substantial growth differences (P <0.001) in terms of biomass accumulation, P acquisition and P utilization efficiency (PUE). Biomass production correlated significantly (P <0.01) with their shoot P uptake and PUE at both P sources, indicating that cultivars efficient in P solublization accumulated more biomass. Higher P uptake by all cultivars was significantly related to the drop in root medium pH, which was presumably owing to H + efflux from the roots supplied with TCP and RP. Higher shoot dry matter of the cultivars at TCP was related to better P acquisition ability, which in turn was related to higher Ca uptake. Thus, cultivars with efficient Ca accumulation ability can acquire higher amounts of P from P-deficient soils and can adapt well to such low-P soil conditions.
KW - Brassica cultivars
KW - Citrate
KW - Malate
KW - P solublization
KW - P uptake
KW - PUE
KW - RP
KW - TCP
UR - http://www.scopus.com/inward/record.url?scp=33748358355&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748358355&partnerID=8YFLogxK
U2 - 10.1111/j.1747-0765.2006.00082.x
DO - 10.1111/j.1747-0765.2006.00082.x
M3 - Article
VL - 52
SP - 623
EP - 633
JO - Soil Science and Plant Nutrition
JF - Soil Science and Plant Nutrition
SN - 0038-0768
IS - 5
ER -