This appendix is primarily concerned with procedures which were developed for the quantitative studies of shoot-apical systems. It includes some suggestions on data processing, but it cannot be said too often that further studies of the kind will demand flexibility of approach and an awareness of the necessity for precision.

The final item is a set of tables for the conversion of relative growth rates (R day−1) to doubling times.

THREE-DIMENSIONAL RECONSTRUCTION

The three-dimensional drawings which are used throughout this book are based on serial sections of the structures they represent. They have been very helpful in portraying changes in form and in identifying critical events in the genesis of form. One of my colleagues has labelled them the Michelin-type drawings, for rather obvious reasons, and others have thought the contour lines were too prominent. However, the lines do contribute greatly to one's awareness of form, as will be seen in Fig. A.2E and F. The procedure has been published in detail (Williams, 1970), but the essentials are repeated here for convenience.

Fig. A.1 illustrates the principles by reference to a sphere of radius 34 μm. Let us suppose that this sphere has been serially sectioned by horizontal planes 10 μm apart, and such that one plane passes through the centre of the sphere. The contour lines of the sphere are shown in plan view in Fig. A.1A superimposed on a square grid whose individual members have sides of 20 μm. The three lower contours are, of course, identical with the three upper ones, and all lie within the equatorial contour.