The Role of Auxin in Plant Embryogenesis

Cooke, Todd J.; Racusen, Richard H.; Cohen, Jerry D.

doi:10.2307/3869733

Cited by 35 publications

(35 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thus, a basic requirement for a synthetic auxin treatment seems to be an underlying feature of somatic embryogenesis (Ammirato, 1985) in a11 cell cultures examined to date. Not only is the exogenous auxin important in the initiation of somatic embryogenesis, but changes in endogenous auxin concentrations may also be critica1 for the later stages of embryogenesis as well (Cooke et al, 1993). It has been shown that embryogenic carrot cells grown in the presence of 2,4-D contain large amounts of IAA (Michalczuk et al, 1992b;Sasaki et al, 1994).…”

mentioning

confidence: 99%

The Effects of Exogenous Auxins on Endogenous Indole-3-Acetic Acid Metabolism (The Implications for Carrot Somatic Embryogenesis)

et al. 1996

View full text Add to dashboard Cite

(D.M.R., N.I., T.J.C.)l h e effect of auxin application on auxin metabolism was investigated in excised hypocotyl cultures of carrot (Daucus carota). Concentrations of both free and conjugated indole-3-acetic acid (IAA), [2H,]IAA, 2,4-dichlorophenoxyacetic acid, and naphthaleneacetic acid (NAA) were measured by mass spectroscopy using stable-isotope-labeled interna1 standards.[l3C1]NAA was synthesized for this purpose, thus extending the range of auxins that can be assayed by stable-isotope techniques. 2,4-Dichlorophenoxyacetic acid promoted callus proliferation of the excised hypocotyls, accumulated as the free form in large quantities, and had minor effects on endogenous IAA concentrations. NAA promoted callus proliferation and the resulting callus became organogenic, producing both roots and shoots. NAA was found mostly in the conjugated form and had minor effects on endogenous IAA concentrations. [ZH,lIAA had no visible effect on the growth pattern of cultured hypocotyls, possibly because it was rapidly metabolized to form inactive conjugates or possibly because it mediated a decrease in endogenous IAA concentrations by an apparent feedback mechanism. l h e presente of exogenous auxins did not affect tryptophan labeling of either the endogenous tryptophan or IAA pools. This suggested that exogenous auxins did not alter the IAA biosynthetic pathway, but that synthetic auxins did appear to be necessary to induce callus proliferation, which was essential for excised hypocotyls to gain the competence to form somatic embryos.Since the 1940s (Thimann, 1974), exogenous auxins have been used frequently as experimental tools for studying their effects in developing structures (Schiavone and Cooke, 1987); for screening for mutants impaired in the uptake, metabolism, and physiology of endogenous auxins (Timpte et al., 1994); and even to find potential IAA receptors (Jones and Venis, 1989; LoSchiavo et al., 1991). One important use for the application of exogenous auxin is as a growth regulator for maintaining plant-cell-and tissue-

show abstract

mentioning

confidence: 99%

The Effects of Exogenous Auxins on Endogenous Indole-3-Acetic Acid Metabolism (The Implications for Carrot Somatic Embryogenesis)

et al. 1996

View full text Add to dashboard Cite

show abstract

“…Appropriate distribution of auxin has been shown to be necessary for a number of developmental processes. Normal embryogenesis, for example, requires auxin transport (Cooke et al, 1993), and the Arabidopsis mutants lop1, pin1-1, and monopterous (Okada et al, 1991;Carland and McHale, 1996;Przemeck et al, 1996), which may be altered in auxin transport, have altered vascular, floral, and pattern development, respectively.…”

mentioning

confidence: 99%

Inhibition of Auxin Movement from the Shoot into the Root Inhibits Lateral Root Development in Arabidopsis

1998

View full text Add to dashboard Cite

In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [ 3 H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

show abstract

“…Leaf fusion in Lupinus (Varnell and Vasil, 1978) and bract and flower fusion in Antirrhinum (Bergbusch, 1999) were found after localised application of auxins to post-embryonic shoot apical meristems. Cooke and coworkers in an overview of some of these and other results have suggested that possibly two overlapping mechanisms for the establishment of the embryonic axis may exist, one operative only in zygotic embryos (a positional mechanism), the other the sole mechanism in somatic embryos (an auxin-mediated mechanism), and that the former arises as a persistent maternal effect (Cooke et al, 1993). This does not altogether coincide with the F3 effect on growth habit/leaf shape in these families and their behaviour in backcrosses, as a maternal bias was not found in these populations.…”

Section: Discussionmentioning

confidence: 99%

Evidence for cytoplasmic inheritance of a developmental organizer affecting growth habit and leaf shape in Antirrhinum majus

Bergbusch¹

2002

Heredity

View full text Add to dashboard Cite

A cross between two distinct, true-breeding plants of Antirrhinum majus L. showed an unexpected pattern of inheritance of growth habit in the F2, which was extended to both growth habit and leaf shape in the F3 generation of all the plants traced further. All the F3 families, offspring of individual F2 plants, were very uniform for both growth habit and leaf shape traits but differed distinctly from each other in these respects. The backcrosses of selected F3 and F4 families to the original parents in the cross did not segregate for the distinctive family phenotypes. This led to the postulate

show abstract

The Role of Auxin in Plant Embryogenesis

Cited by 35 publications

References 5 publications

The Effects of Exogenous Auxins on Endogenous Indole-3-Acetic Acid Metabolism (The Implications for Carrot Somatic Embryogenesis)

The Effects of Exogenous Auxins on Endogenous Indole-3-Acetic Acid Metabolism (The Implications for Carrot Somatic Embryogenesis)

Inhibition of Auxin Movement from the Shoot into the Root Inhibits Lateral Root Development in Arabidopsis

Evidence for cytoplasmic inheritance of a developmental organizer affecting growth habit and leaf shape in Antirrhinum majus

Contact Info

Product

Resources

About