Growth activity of fusiform initials in storeyed cambium

Abstract

The intrusive growth of fusiform initials was studied in <i>Entandrophragma</i>, This growth makes possible a change in the position of the cell ends of one storey in respect to those in the neighbouring storey, and this is 'turn leads to changes in the orientation of cambial initials. The growth activities of the oppositely directed ends of the same initial are not the same. Not all cell ends are simultaneously actiye. There are groups of ends distributed alternately in a storey which are active or inactive, so that a pattern of growth activity appears in the cambium. The activity of a particular cell end changes in successive time periods. Owing to this, the rate of creeping of one end past. those of the adjoining storey varies. This phenomenon of changes in the activity of cell ends in time may be referred to the phenomenon of the appearance of the growth activity pattern on the cambium surface under the hypothesis of transverse shifting of the elements of this pattern ("active" and. "inactive" groups) in relation to the cambial initials.