Hormonal and cell division analyses in Watsonia lepida seedlings

Glendon D. Ascough, Ondřej Novák, Aleš Pěnčík, Jakub Rolčík, Miroslav Strnad, John E. Erwin, Johannes Van Staden

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The regeneration ability, cell division activity, auxin and cytokinin content of seedling regions and hypocotyl subsections of Watsonia lepida were studied. A total of 21 different cytokinins or conjugates were found in seedlings, with the highest cytokinin content in meristematic regions (root and shoot apical meristems). The greatest contribution to the cytokinin pool came from the biologically inactive cZRMP, suggesting that significant de novo synthesis was occurring. Five different auxins or conjugates were detected, being concentrated largely in the shoot apical meristem and leaves, IAA being the most abundant. Analysis of hypocotyl subsections (C1-C4) revealed that cell division was highest in subsection C2, although regeneration in vitro was significantly lower than in subsection C1. Anatomically, subsection C1 contains the apical meristem, and hence has meristematic cells that are developmentally plastic. In contrast, subsection C2 has cells that have recently exited the meristem and are differentiating. Despite high rates of cell division, cells in subsection C2 appear no longer able to respond to cues that promote proliferation in vitro. Auxin and cytokinin analyses of these subsections were conducted. Possibly, a lower overall cytokinin content, and in particular the free-base cytokinins, could account for this observed difference.

Original languageEnglish (US)
Pages (from-to)1497-1507
Number of pages11
JournalJournal of Plant Physiology
Volume166
Issue number14
DOIs
StatePublished - Sep 15 2009

Bibliographical note

Funding Information:
We are grateful to the National Research Foundation, Pretoria, and the University of Minnesota Agriculture Experiment Station and the Minnesota Nursery and Landscape Foundation, for generous financial assistance. This work was also supported by the Ministry of Education, Youth and Sports of the Czech Republic (MSM 6198959216).

Keywords

  • Auxin
  • Cytokinin
  • Differentiation
  • Meristem
  • Totipotency

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