Abstract
The metabolism of [1-14C]2,4-dichlorophenoxyacetic acid (2,4-D) in soybean (Glycine max [L.] Merrill var. Amsoy) root callus and in differentiated soybean root cultures was investigated as a function of pesticide concentration and age of tissue. The chronological age of the tissue was found to be correlated with the mitotic index which reached a peak at 2 weeks and then declined. The metabolism of 2,4-D changed with age of the root callus tissue. The amount of free 2,4-D found in 3-week-old root callus tissue rapidly increased as the concentration of 2,4-D in the medium was increased from 10−6 to 10−5 molar, whereas the low level of aqueous (glycosides) and ether soluble metabolites (2,4-D amino acid conjugates) increased slowly. With 9-week-old root callus tissue, the amount of free 2,4-D remained at a relatively low, constant level (saturation level) as the concentration of 2,4-D in the medium increased. Under these conditions the aqueous metabolites increased only slightly but the ether fraction (2,4-D amino acid conjugates) rapidly increased. Thus, the older root callus tissue appeared to regulate the level of free 2,4-D at about 4 nanomoles per gram by converting any excess 2,4-D into amino acid conjugates.
In 3-week-old, differentiated root cultures the metabolism of 2,4-D closely paralleled the metabolism found in the older 9-week-old callus tissue. The saturation level of free 2,4-D found in this tissue was only about 1 to 2 nanomoles per gram.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Andreae W. A., Good N. E. Studies on 3-Indoleacetic Acid Metabolism. IV. Conjugation with Aspartic Acid and Ammonia as Processes in the Metabolism of Carboxylic Acids. Plant Physiol. 1957 Nov;32(6):566–572. doi: 10.1104/pp.32.6.566. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bandurski R. S., Schulze A. Concentration of Indole-3-acetic Acid and Its Derivatives in Plants. Plant Physiol. 1977 Aug;60(2):211–213. doi: 10.1104/pp.60.2.211. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Feung C. S., Hamilton R. H., Mumma R. O. Metabolism of 2,4-dichlorophenoxyacetic acid. 11. Herbicidal properties of amino acid conjugates. J Agric Food Chem. 1977 Jul-Aug;25(4):898–900. doi: 10.1021/jf60212a013. [DOI] [PubMed] [Google Scholar]
- Feung C. S., Hamilton R. H., Mumma R. O. Metabolism of Indole-3-Acetic Acid: III. Identification of Metabolites Isolated from Crown Gall Callus Tissue. Plant Physiol. 1976 Nov;58(5):666–669. doi: 10.1104/pp.58.5.666. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Feung C. S., Hamilton R. H., Witham F. H., Mumma R. O. The relative amounts and identification of some 2,4-dichlorophenoxyacetic Acid metabolites isolated from soybean cotyledon callus cultures. Plant Physiol. 1972 Jul;50(1):80–86. doi: 10.1104/pp.50.1.80. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Feung C. S., Mumma R. O., Hamilton R. H. Metabolism of 2,4-dichlorophenoxyacetic acid. VI. Biological properties of amino acid conjugates. J Agric Food Chem. 1974 Mar-Apr;22(2):307–309. doi: 10.1021/jf60192a040. [DOI] [PubMed] [Google Scholar]
- Feung C., Hamilton R. H., Mumma R. O. Metabolism of 2,4-dichlorophenoxyacetic acid. V. Identification of metabolites in soybean callus tissue cultures. J Agric Food Chem. 1973 Jul-Aug;21(4):637–640. doi: 10.1021/jf60188a058. [DOI] [PubMed] [Google Scholar]
- Kang B. G., Newcomb W., Burg S. P. Mechanism of Auxin-induced Ethylene Production. Plant Physiol. 1971 Apr;47(4):504–509. doi: 10.1104/pp.47.4.504. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Venis M. A. Auxin-induced Conjugation Systems in Peas. Plant Physiol. 1972 Jan;49(1):24–27. doi: 10.1104/pp.49.1.24. [DOI] [PMC free article] [PubMed] [Google Scholar]