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Nutrient uptake, cluster root formation and exudation of protons and citrate in Lupinus albus as affected by localized supply of phosphorus in a split-root system

Authors :
Haigang Li
Fusuo Zhang
Jianbo Shen
G. Neumann
Source :
Plant Science. 168:837-845
Publication Year :
2005
Publisher :
Elsevier BV, 2005.

Abstract

White lupin ( Lupinus albus L. cv. Amiga) plants were grown in nutrient solution, using a split-root system with two compartments to examine the effect of localized phosphorus (P) supply on nutrient uptake, cluster root formation and root exudation. Phosphorus was supplied at 0 and 250 μM P in the −P and +P compartments, respectively, with three treatments of −P+P, −P−P and +P+P. Shoot dry weight in −P+P was higher than that in −P−P, but not significantly different from that in +P+P. Shoot P concentration [P] in −P+P was lower than that in +P+P, but higher than that in −P−P. In the −P+P treatment, root [P] was lower in the −P than in the +P root half and the similar trend was observed for root dry weight. Compared with −P−P, 19% of P uptake in the +P root half in −P+P was translocated to the −P root half. Phosphorus deficiency decreased K, Mg and S uptake in −P−P, and localized P deficiency reduced S uptake in the −P root half in −P+P. The number of cluster roots and exudation rates of protons, citrate and acid phosphatase (APase) in both root halves were higher in −P−P than in +P+P. The localized P supply increased the total number of cluster roots in the +P root half compared with the −P root half in −P+P. Compared with −P−P, the localized P supply significantly increased the shoot [P] and decreased the exudation rate of citrate and APase in both root halves in −P+P. Exudation rate of citrate in the −P root half in −P+P was higher than that of the +P root half in +P+P. Localized P supply reduced proton release in the +P and even −P root halves in −P+P, but the pH was lower in the −P than +P compartments for the individual plant, indicating a significant effect of the localized P supply on proton release. The results suggest that cluster root formation and citrate exudation are regulated by the shoot [P] and affected by localized supply of external P, and that proton release is inhibited by localized P supply by altering the balance of anion and cation uptake.

Details

ISSN :
01689452
Volume :
168
Database :
OpenAIRE
Journal :
Plant Science
Accession number :
edsair.doi...........aaec1bbea73fb57f7591b0a307af6103
Full Text :
https://doi.org/10.1016/j.plantsci.2004.10.017