Sieve Plate Pores and Plasmodesmata, the Communication Channels of the Symplast: Ultrastructural Aspects and Developmental Relations

This paper is based on the lecture entitled “Communication Channels Between Cells and Their Origin in Higher Plants” presented by K. E. on 14 May 1984 at the University of California‐Davis as part of the Department of Botany Symposium “Integrating Plant Structure and Function.” This symposium was arranged in connection with the UCD 75th Anniversary Celebration. The main theme of the paper is the developmental relation between the plasmodesmata and the sieve plate pores in the phloem conduits of several dicotyledons. New observations and a review of some pertinent data from the literature are combined.