Submitted to: Proceedings of International Conference on Root Biology
Publication Type: Abstract only
Publication Acceptance Date: 7/28/1997
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: White lupin (Lupinus albus L.) develops proteoid or cluster root morphology when subjected to phosphate stress. These densely clustered, short lateral roots are the site of organic acid and APase secretion and increased PEPC activity. While auxin has been implicated in the initiation and development of proteoid roots, little evidence to support this hypothesis is available. .To gain further insight into the relationship between auxin and the induction of proteoid roots, attempts were made to modify auxin transport during the early stages of lateral root development. In separate experiments, auxin transport inhibitors NPA (N-(1-napthyl) phthalamic acid) and TIBA (2,3,5-triiodobenzoic acid) were added to both +P and -P nutrient solutions and applied to the lupin plants at 4 and 8 days after emergence. The inhibitors were found to limit proteoid root formation in the -P treatments while having no apparent effects on root formation in +P treatments or shoot morphology in either treatment. Also, in the -P treatments, the addition of NPA and TIBA reduced phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase (MDH) activities in the proteoid root segments as compared to the proteoid segments of the -P control plants.