Abstract
The effects of altered endogenous indole-3-acetic (IAA) levels on elongation in garden pea (Pisum sativum L.) plants were investigated. The auxin transport inhibitors 2,3,5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA) were applied to elongating internodes of wild-type and mutant lkb plants. The lkb mutant was included because elongating lkb internodes contained 2- to 3-fold less free IAA than those of the wild type. In the wild type, TIBA reduced both the IAA level and internode elongation below the site of application. Both TIBA and HFCA strongly promoted the elongation of lkb internodes and also raised IAA levels above the application site. The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) also markedly increased internode elongation in lkb plants and virtually restored petioles and tendrils to their wild-type length. In contrast, treatment of wild-type plants with TIBA, HFCA, or 2,4-D caused little or no increase in elongation above the application site. The ethylene synthesis inhibitor aminoethoxyvinylglycine also increased stem elongation in lkb plants, and combined application of HFCA and aminoethoxy-vinylglycine restored lkb internodes to the wild-type length. It is concluded that the level of IAA in wild-type internodes is necessary for normal elongation, and that the reduced stature of lkb plants is at least partially attributable to a reduction in free IAA level in this mutant.
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Selected References
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- King P. J. Plant hormone mutants. Trends Genet. 1988 Jun;4(6):157–162. doi: 10.1016/0168-9525(88)90021-2. [DOI] [PubMed] [Google Scholar]
- Liu Cm., Xu Zh., Chua N. H. Auxin Polar Transport Is Essential for the Establishment of Bilateral Symmetry during Early Plant Embryogenesis. Plant Cell. 1993 Jun;5(6):621–630. doi: 10.1105/tpc.5.6.621. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reid J. B. Internode length in pisum: do the internode length genes effect growth in dark-grown plants? Plant Physiol. 1983 Jul;72(3):759–763. doi: 10.1104/pp.72.3.759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Romano C. P., Hein M. B., Klee H. J. Inactivation of auxin in tobacco transformed with the indoleacetic acid-lysine synthetase gene of Pseudomonas savastanoi. Genes Dev. 1991 Mar;5(3):438–446. doi: 10.1101/gad.5.3.438. [DOI] [PubMed] [Google Scholar]
- Thimann K. V., Bonner W. D. THE ACTION OF TRI-IODOBENZOIC ACID ON GROWTH. Plant Physiol. 1948 Jan;23(1):158–161. doi: 10.1104/pp.23.1.158. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yang T., Law D. M., Davies P. J. Magnitude and Kinetics of Stem Elongation Induced by Exogenous Indole-3-Acetic Acid in Intact Light-Grown Pea Seedlings. Plant Physiol. 1993 Jul;102(3):717–724. doi: 10.1104/pp.102.3.717. [DOI] [PMC free article] [PubMed] [Google Scholar]