Planta

, Volume 176, Issue 2, pp 248–255

Cytoplasmic free calcium in Riccia fluitans L. and Zea mays L.: Interaction of Ca2+ and pH?

  • Hubert Felle
Article

DOI: 10.1007/BF00392452

Cite this article as:
Felle, H. Planta (1988) 176: 248. doi:10.1007/BF00392452

Abstract

In cells of Zea mays (root hairs, coleoptiles) and Riccia fluitans (rhizoids, thalli) intracellular Ca2+ and pH have been measured with double-barrelled microelectrodes. Free Ca2+ activities of 109–187 nM (Riccia rhizoids), 94–160 nM (Riccia thalli), 145–231 nM (Zea root hairs), 84–143 nM (Zea coleoptiles) were found, and therefore identified as cytoplasmic. In a few cases (Riccia rhizoids), free Ca2+ was in the lower millimolar range (2.3±0.8 mM). A change in external Ca2+ from 0.1 to 10 mM caused an initial and short transient increase in cytoplasmic free Ca2+ which finally levelled off at about 0.2 pCa unit below the control, whereas in the presence of cyanide the Ca2+ activity returned to the control level. It is suggested that this behaviour is indicative of active cellular Ca2+ regulation, and since it is energy-dependent, may involve a Ca2+-ATPase. Acidification of the cytoplasmic pH and alkalinization of the vacuolar pH lead to a simultaneous increase in cytoplasmic free Ca2+, while alkalinization of pHc decreased the Ca2+ activity. Since this is true for such remote organisms as Riccia and Zea, it may be concluded that regulation of cytoplasmic pH and free Ca2+ are interrelated. It is further concluded that double-barrelled microelectrodes are useful tools for investigations of intracellular ion activities in plant cells.

Key words

Calcium (free, and pH)Cytoplasm (free Ca2+, pH)Microelectrode, double-barrelled, Ca2+pH(interaction with Ca2+)RicciaZea (free Ca2+ and pH)

Symbols and abbreviations

Ψm, ΔΨm

membrane potential difference, changes thereof

PVC

polyvinylchloride

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Hubert Felle
    • 1
  1. 1.Botanisches Institut IJustus Liebig-UniversitätGiessenFederal Republic of Germany