COMPUTER PROGRAM FOR THREE‐DIMENSIONAL RECONSTRUCTIONS AND NUMERICAL ANALYSES OF PLANT ORGANS FROM SERIAL SECTIONS

A computer program (SECTION) is presented which allows for the three-dimensional reconstruction of serial cross sections through biological materials. The program provides a numerical analysis of perimeter length and transverse area of each anatomical feature designated in a cross section, as well as surface area and volume computations for features that pass from one section to another. In addition to rotating and tilting the 3-D reconstruction in any desired orientation, the program has editing capabilities which allow different combinations of anatomical features to be shown in neutral gray outline or interconnected by colored lines. COMPUTER GRAPHICS represents a convenient tool for rendering conventional serial sections in three-dimensions (Delozier et al., 1987). In addition, calculations on surface areas and volumes of anatomical features in cross sections and serial cross sections are equally useful (Weibel, 1979; Calkin, Gibson, and Nobel, 1985; Meicenheimer, 1986). We present a computer program, SECTION, that was specifically designed to deal with serial sections through biological materials in both a graphics and numerical mode. SECTION contains a "user-friendly" interface to gain acceptance in a teaching environment. The program operates at full potential on an IMB PC-XT or compatible hardware and is closely tied to the IBMPC Graphics Toolkit. However, SECTION can be easily modified to use another graphics subroutine library from PASCAL. Consequently, SECTION and the necessaary hardware are within the space and economic reach of most biological laboratories interested in anatomical and/or morphological research projects. The program provides 1) three-dimensional reconstructions (currently, as many as nine separate categories of anatomical features can be disI Received for publication 16 February 1987; revision accepted 6 May 1987. We thank Dr. Dominick J. Paolillo, Jr. (Plant Biology, Cornell University), for providing us with plant sections used to demonstrate the capabilities of our program, and Mr. Kent E. Loeffler (staff photographer for Plant Pathology, Cornell University) for printing the color negatives used in Fig. 1-8. Funding for this research was provided by NSF grant BSR-8320272 and Cornell University Project Ezra #4. Funding for preparing and reproducing the color graphics in Fig. 1-8 was provided by a grant from the IBM Corporation. played); 2) numerical analyses of perimeter length, transverse and surface area, and volume; and 3) versatile editorial formats that permit the user to specify the features displayed, connected through successive cross sections, or projected onto two-dimensional surfaces (as for example, conventional phyllotactic "stick diagrams"). SECTION was written in PASCAL using the IBM/Microsoft Pascal Compiler and the IBM Graphics Toolkit. An ideal system configuration for using SECTION consists of an IBMPC with 512K of memory, math co-processor, hard-disk storage, and an enhanced graphics board. A digitizing pad is required for the recording of section data and a color plotter may be used for hard-copy output. The system may be modified for the use of other input and output peripherals with little effort. The program is available on floppy disk (upon request to the senior author) along with a user's manual. These items will be made available at minimum cost. MATERIALS AND METHODS-I. Preparation of serial sections -Freehand sections through the nodal and internodal anatomy of Coleus blumei Benth. were prepared, wet-mounted on slides, and traced by means of camera lucida. Coleus was selected because it is a favored organism in teaching and research contexts, and because its anatomy has been explored in great detail. Freehand sections were used in this study because they represent the level of minimal information that could be anticipated to be supplied by a student or novice research assistant. Accordingly, the reconstructions that