Calcium delays the onset of cell division and rhizoid elongation in gemmae of the calcifuge fern, Vittaria graminifolia
1993
Sabba, R.P. | Miller, J.H.
Vittaria graminifolia gametophytes reproduce asexually by linear six-celled propagules known as gemmae. It has been shown previously that asymmetric cell division and rhizoid elongation in gemmae are inhibited by millimolar concentrations of Ca++. The present paper shows that millimolar Ca++ delays the onset of cell division at a point prior to mitosis, without affecting the maximal rate of cell division. Ca++ is most effective in delaying cell division when it is present during the first 24 hours of culture, 2 or 3 days before the initiation of cell division. Millimolar Ca++ inhibits rhizoid elongation by delaying its onset, while also reducing its maximal rate. Ca++ is also most effective in delaying rhizoid elongation during the first 24 hours of culture. Culture of gemmae on Ethylglycol-bis-(aminoethyl ether)-N,N,N',N'-tetraacetic acid-buffered media shows that the maximum frequency of cell division occurs at pCa 7, while for the initiation of rhizoid elongation, it occurs at pCa 5.
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