This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Davidonis, G. H. Articles by Mumma, R. O. Search for Related Content PubMed PubMed Citation Articles by Davidonis, G. H. Articles by Mumma, R. O. Agricola Articles by Davidonis, G. H. Articles by Mumma, R. O.

Articles

Comparative Metabolism of 2,4-Dichlorophenoxyacetic Acid in Cotyledon and Leaf Callus from Two Varieties of Soybean ¹

Pesticide Research Laboratory and Graduate Study Center, The Pennsylvania State University, University Park, Pennsylvania 16802, Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania 16802, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802

Only quantitative differences were observed in the metabolism of [1-¹⁴C]2,4-dichlorophenoxyacetic acid (2,4-D) by soybean cotyledon callus as influenced by variety (Acme and Amsoy), source of tissue (cotyledon, leaf and root) and age. All tissues metabolized 2,4-D to water-soluble (glycosides) and ether-soluble (primarily amino acid conjugates) metabolites.

In young (3- to 4-week-old) Amsoy cotyledon or leaf callus tissue the free 2,4-D increased proportionately with the external 2,4-D concentration while in older (6- to 8-week-old) tissue the amino acid conjugates increased in this manner. Thus, in the older Amsoy tissue apparent regulation of the internal 2,4-D level (1.5-3.5 nmoles per gram fresh weight) was observed. In 3- or 6-week-old Acme cotyledon callus 2,4-D accumulated with an increase in the external 2,4-D concentration with no evidence for regulation of internal 2,4-D levels.