Abstract
Plants grown in highly weathered or highly alkaline calcareous soils often experience phosphorus (P) stress but never a P-free environment. Thus, applications of mineral P fertilizers are often required to achieve maximum yield, but recovery of applied P fertilizers is notoriously low. Phosphorus deprivation elicits a complex array of morphological, physiological, and biochemical adaptations among plant species and genotypes to enhance P acquisition and utilization efficiency. Ten Brassica cultivars were grown hydroponically to investigate their relative efficiency to utilize deficiently (20-μM) and adequately (200-μM) supplied P, using Johnson's modified solution. Cultivars differed significantly (P <0.001) in biomass accumulation. Orthophosphate concentration and uptake in shoot and root, absolute and relative growth rate, and P-utilization efficiency (PUE) were also significantly different among various Brassica cultivars. Root-shoot ratio and specific absorption rate were substantially increased in plants subjected to low P supply. Shoot and root dry-matter yield as well as total biomass production correlated significantly (P <0.01) with their total P uptake and PUE. Cultivars, which were efficient in P utilization, were also efficient accumulators of biomass under adequate as well as deficient levels of P supply. As part of the study, kinetic parameters of P uptake were evaluated for six contrasting Brassica cultivars in PUE, grown in nutrient solution. The kinetic parameters related to P influx were maximal transport rate (Vmax), the Michaelis-Menten constant (Km), and the external concentration when net uptake is zero (Cmin). Lower Km and Cmin values were indicative of P-uptake ability of the cultivars, evidencing their adaptability to P-stress conditions. In another experiment, six cultivars were exposed to no P nutrition for 27 days after initial feeding on optimum nutrition for 14 days. All the cultivars retranslocated P from aboveground parts to their roots during growth in P-free conditions, the magnitude of which was variable in different cultivars. Phosphorus concentration at 41 days after transplanting was higher in developing leaves than developed leaves. Translocation of absorbed P from metabolically inactive sites to active sites in plants growing under P-stress conditions may have helped the tolerant cultivars to establish a better rooting system, which provided basis for tolerance against P-deficiency stress and increased PUE.
| Original language | English |
|---|---|
| Pages (from-to) | 1061-1085 |
| Number of pages | 25 |
| Journal | Communications in Soil Science and Plant Analysis |
| Volume | 38 |
| Issue number | 7-8 |
| DOIs | |
| Publication status | Published - Apr 2007 |
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Keywords
- Brassica cultivars
- Kinetic parameters
- P-utilization efficiency
- PSF
- Relative growth rate
- Specific absorption ratio
ASJC Scopus subject areas
- Soil Science
- Agronomy and Crop Science
- Plant Science
- Analytical Chemistry
Cite this
Relative phosphorus utilization efficiency, growth response, and phosphorus uptake kinetics of brassica cultivars under a phosphorus stress environment. / Akhtar, M. Shahbaz; Oki, Yoko; Adachi, Tadashi; Murata, Yoshiyuki; Khan, Md H R.
In: Communications in Soil Science and Plant Analysis, Vol. 38, No. 7-8, 04.2007, p. 1061-1085.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Relative phosphorus utilization efficiency, growth response, and phosphorus uptake kinetics of brassica cultivars under a phosphorus stress environment
AU - Akhtar, M. Shahbaz
AU - Oki, Yoko
AU - Adachi, Tadashi
AU - Murata, Yoshiyuki
AU - Khan, Md H R
PY - 2007/4
Y1 - 2007/4
N2 - Plants grown in highly weathered or highly alkaline calcareous soils often experience phosphorus (P) stress but never a P-free environment. Thus, applications of mineral P fertilizers are often required to achieve maximum yield, but recovery of applied P fertilizers is notoriously low. Phosphorus deprivation elicits a complex array of morphological, physiological, and biochemical adaptations among plant species and genotypes to enhance P acquisition and utilization efficiency. Ten Brassica cultivars were grown hydroponically to investigate their relative efficiency to utilize deficiently (20-μM) and adequately (200-μM) supplied P, using Johnson's modified solution. Cultivars differed significantly (P <0.001) in biomass accumulation. Orthophosphate concentration and uptake in shoot and root, absolute and relative growth rate, and P-utilization efficiency (PUE) were also significantly different among various Brassica cultivars. Root-shoot ratio and specific absorption rate were substantially increased in plants subjected to low P supply. Shoot and root dry-matter yield as well as total biomass production correlated significantly (P <0.01) with their total P uptake and PUE. Cultivars, which were efficient in P utilization, were also efficient accumulators of biomass under adequate as well as deficient levels of P supply. As part of the study, kinetic parameters of P uptake were evaluated for six contrasting Brassica cultivars in PUE, grown in nutrient solution. The kinetic parameters related to P influx were maximal transport rate (Vmax), the Michaelis-Menten constant (Km), and the external concentration when net uptake is zero (Cmin). Lower Km and Cmin values were indicative of P-uptake ability of the cultivars, evidencing their adaptability to P-stress conditions. In another experiment, six cultivars were exposed to no P nutrition for 27 days after initial feeding on optimum nutrition for 14 days. All the cultivars retranslocated P from aboveground parts to their roots during growth in P-free conditions, the magnitude of which was variable in different cultivars. Phosphorus concentration at 41 days after transplanting was higher in developing leaves than developed leaves. Translocation of absorbed P from metabolically inactive sites to active sites in plants growing under P-stress conditions may have helped the tolerant cultivars to establish a better rooting system, which provided basis for tolerance against P-deficiency stress and increased PUE.
AB - Plants grown in highly weathered or highly alkaline calcareous soils often experience phosphorus (P) stress but never a P-free environment. Thus, applications of mineral P fertilizers are often required to achieve maximum yield, but recovery of applied P fertilizers is notoriously low. Phosphorus deprivation elicits a complex array of morphological, physiological, and biochemical adaptations among plant species and genotypes to enhance P acquisition and utilization efficiency. Ten Brassica cultivars were grown hydroponically to investigate their relative efficiency to utilize deficiently (20-μM) and adequately (200-μM) supplied P, using Johnson's modified solution. Cultivars differed significantly (P <0.001) in biomass accumulation. Orthophosphate concentration and uptake in shoot and root, absolute and relative growth rate, and P-utilization efficiency (PUE) were also significantly different among various Brassica cultivars. Root-shoot ratio and specific absorption rate were substantially increased in plants subjected to low P supply. Shoot and root dry-matter yield as well as total biomass production correlated significantly (P <0.01) with their total P uptake and PUE. Cultivars, which were efficient in P utilization, were also efficient accumulators of biomass under adequate as well as deficient levels of P supply. As part of the study, kinetic parameters of P uptake were evaluated for six contrasting Brassica cultivars in PUE, grown in nutrient solution. The kinetic parameters related to P influx were maximal transport rate (Vmax), the Michaelis-Menten constant (Km), and the external concentration when net uptake is zero (Cmin). Lower Km and Cmin values were indicative of P-uptake ability of the cultivars, evidencing their adaptability to P-stress conditions. In another experiment, six cultivars were exposed to no P nutrition for 27 days after initial feeding on optimum nutrition for 14 days. All the cultivars retranslocated P from aboveground parts to their roots during growth in P-free conditions, the magnitude of which was variable in different cultivars. Phosphorus concentration at 41 days after transplanting was higher in developing leaves than developed leaves. Translocation of absorbed P from metabolically inactive sites to active sites in plants growing under P-stress conditions may have helped the tolerant cultivars to establish a better rooting system, which provided basis for tolerance against P-deficiency stress and increased PUE.
KW - Brassica cultivars
KW - Kinetic parameters
KW - P-utilization efficiency
KW - PSF
KW - Relative growth rate
KW - Specific absorption ratio
UR - http://www.scopus.com/inward/record.url?scp=34247257951&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34247257951&partnerID=8YFLogxK
U2 - 10.1080/00103620701280266
DO - 10.1080/00103620701280266
M3 - Article
AN - SCOPUS:34247257951
VL - 38
SP - 1061
EP - 1085
JO - Communications in Soil Science and Plant Analysis
JF - Communications in Soil Science and Plant Analysis
SN - 0010-3624
IS - 7-8
ER -