Growth and development of shoot apex in barley. III. Study of growth rate variation by means of the growth tensor

Silhouette of the shoot apical dome of barley does not change in time during early generative phase, although the dome height varies cyclically and increases in successive plastochrons. The elongation is limited to the dome region, the young frusta do not elongate. Relative rate of elongation (per plastochron) of the dome as a whole, decreases with increasing dome height. In the protoderm there are packets of cells distinguished by thicker walls. The growth tensor in prolate spheroidal coordinate system was applied to analysis of growth rate distribution within the dome. The meridional displacement velocities on dome surface, which are needed for the analysis, were determined on the basis of cell packet length expressed as a position function. Maximum relative elemental rate of growth occurs in subdistal zone.