Ceratopteris pteridoides根尖之頂端細胞分裂

The time of mitosis in the root apical cell of Ceratopteris Pteridoides

This work is concerned with cell division and nuclear abnormalities in the root apical cell and its close derivatives of a water fern, Ceratopteris pteridoides (Hook.) Hieron. when grown either in the presence or absence of a colchicine solution. The apical cells of rapidly growing roots divide mainly after midnight. An important consequence of applying colchicine is the formation of multinucleate cells. The formation of ameboid nuclei and other nucleotoxic effects occur as the time of colchicine is prolonged. By counting the number of nuclei formed after a 24 hour-colchicine-treatment, the nuclear cycle of the apical cells in some of the roots of this fern seems to be very short. It was estimated about as 8 hours or shorter. It newer divides less frequently than its adjacent cells. The concept that the apical cell in pteridophytes is an ''unicellular quiescent center'' suggested by some workers is also discussed.