|Knight, Diane - UNIVERSITY OF MINNESOTA|
|Allan, Deborah - UNIVERSITY OF MINNESOTA|
Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 1996
Publication Date: N/A
Technical Abstract: White lupin (Lupinus albus L.) develops proteoid roots when grown in phosphorus deficient conditions. These short, lateral, densely clustered roots are adapted to increasing the availability of P to lupin. Previous work from our laboratory showed proteoid roots to have enhanced nonphotosynthetic C fixation and altered metabolism to support organic acid dexudation, which serves to solubilize P in the rhizosphere. The present work indicates that proteoid roots possess other adaptations for increasing P availability and possibly for conserving P in the plant. Acid phosphatase (APase) activity was higher at the surface of proteoid roots than non-proteoid roots. The higher surface activity was the result of increased secretion rather than increased endogenous concentrations of APase and the timing of proteoid root specific APase exudation appears to correspond to that of organic acid exudation. One potential adaptation for rconserving P is through the implementation of the alternative oxidase respiratory pathway. The involvement of the alternative oxidase pathway will be discussed. This research was supported, in part, by the NRICGP grant USDA/93-371000-8941.