Changes in Poparity of Growth During Leaf Initiation in the Pea, Pisum sativum L.

Publisher Website
Google Scholar
Abstract
In the apical dome of the pea shoot apex the axis of growth of the epidermal cells becomes predominantly longitudinal in the I1 region one plastochron before a leaf is initiated, and this orientation persists into the young primordium. In contrast, in the underlying, non-epidermal cells the growth axis in the I1 region becomes randomized half a plastochron before leaf initiation, but in the young primordium it becomes the same as in the epidermis. The initiation of a leaf primordium therefore takes place without any major change in the orientation of growth axes in the epidermis. A controlling role for the epidermis is therefore suggested. No marked reorientation of the growth axis occurs on the sides of the newly initiated primordium. The shape of the young primordium can be related to the differential rates of growth and division within it rather than to changes in growth orientation.