Effects of exogenously applied jasmonates on growth and intracellular pH in maize coleoptile segments

H. R. Irving*, G. Dyson, R. McConchie, R. W. Parish, Christoph Gehring

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The effects of jasmonic acid (JA) on elongation growth of coleoptile segments from etiolated maize (Zea mays L.) were investigated in the presence and absence of auxin. When supplied alone, at physiological concentrations (10-9, 10-8, and 10-5 M), JA (or methyl-JA) inhibited growth. JA at a similar range of concentrations also inhibited auxin-induced elongation growth. To determine whether this effect on growth depended on endogenous abscisic acid (ABA), we grew maize coleoptiles in the presence of norflurazon (an inhibitor of carotenoid biosynthesis) that results in reduced endogenous ABA levels. Growth of etiolated coleoptile segments from these plants was inhibited by JA (or methyl-JA) in both the absence and presence of auxin. Previously, we have observed a correlation between elongation growth and cytosolic pH (pH(i)), in which auxin lowers pH(i), and growth inhibitors such as ABA raise pH(i). We examined the effect of low concentrations of methyl-JA on pH(i) with dual emission dye, carboxy seminaphthorhodafluor-1, and confocal microscopy. To confirm these studies, we also used in vivo 31P NMR spectrometry to ascertain the changes in pH(i) after addition of jasmonate to maize coleoptiles. Coleoptiles grown in either the absence or presence of norflurazon responded to methyl-JA or JA by increases in pH(i) of approximately 0.2 pH unit. This response occurs over a period of 15-20 min and appears to be independent of endogenous ABA. This alkalization induced by JA is likely to form a permissive environment for JA signal transduction pathway(s).

Original languageEnglish (US)
Pages (from-to)93-100
Number of pages8
JournalJournal of Plant Growth Regulation
Volume18
Issue number2
DOIs
StatePublished - Jan 1 1999

Keywords

  • Absicic acid
  • Auxin
  • Cytosolic pH
  • Growth
  • Jasmonic acid
  • Zea mays

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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