The comparative analysis of plant hormones was undertaken on a 1-naphthaleneacetic acid tolerant mutant and normal tobacco (Nicotiana tabacum cv Xanthi) plantlets. The mutant plantlet was scrubby and impaired in its root morphogenesis. Degeneration of the root meristem was studied on tissue sections; it appeared very fast (as early as the 3rd or 4th day after sowing), after which the root was further transformed into a callus. Indoleacetic acid (IAA), abscisic acid (ABA), and the isopentenyladenine (iP)-and trans-zeatin(Z)-type cytokinin levels were measured in terminal buds and root tips 13 days after sowing, by enzyme linked immunosorbent assay of high performance liquid chromatography fractions. Some differences appeared between the apical buds of the two genotypes, but the mutant tobacco differed from the wild type mainly by the presence of higher levels of IAA, ABA, and iP + isopentenyladenosine (iPA) in its small root. Thus, the IAA, ABA, and iP + iPA contents were increased by a factor of 15, 7, and 24 times, respectively, in mutant root compared to wild-type tobacco roots. Previous work has shown that the mutation impairs membrane polarization effects induced by auxin at the cell level. The present results would favor the hypothesis that the mutation has also affected the control of growth regulator accumulation in tissues.Mutant plants, whatever their origin, can be used to obtain a better knowledge about plant physiology. During the last years, different monogenic mutants deficient in (or resistant to) plant growth substances were obtained: to ABA (14), to IAA (3), to gibberellins (15), and to cytokinins (2). Thus, the NAA' resistant tobacco mutant obtained by Muller et al. (23), which was characterized by its inability to root, provided a new tool to study the process of rhizogenesis.The aim of this work was to gain knowledge about the hormonal characteristics of the mutant as well as to describe the root degeneration. Therefore, using an immunoenzymic method (16,20, 25), we have quantified, in different tissues, the amounts of ABA, IAA, and cytokinins in tobacco seedlings, comparing the wild type with the 'rootless' mutant. We tested the hypothesis that the root degeneration, due to the ' Abbreviations: NAA, 1-naphthaleneacetic acid; ELISA, enzyme linkedimmunosorbent assay;iP, isopentenyladenine; iPA, isopentenyladenosine; Z, trans-zeatin; ZR, trans-zeatin riboside. mutation, was the result of a hormone deficit or an alteration in plant hormone metabolism. MATERIALS AND METHODS Plant MaterialWild-type tobacco (clone D8) and mutant tobacco (clone 36) seeds (Nicotiana tabacum cv Xanthi) were obtained from plants grown in greenhouses (INRA, Versailles, France). The NAA resistant dominant mutant tobacco was selected in vitro from mutagenized population of haploid mesophyll protoplasts (5, 23).The seeds were soaked for 20 min in 5% calcium hypochloride aqueous solution and then sown aseptically in glass pots (13 x 10 cm) containing a twice diluted, hormone-free, Murashige and Skoog agar medium (6 ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.