title: The development of the sieve elements of Pinus pinea.
abstract: The fine structure found in the developing and mature secondary phloem of Pinus pinea is described. No longitudinal system of conduits in the sieve elements has been found at any stage in their differentiation. The endoplasmic reticulum undergoes a characteristic series of changes and possible functions are considered. The nature of the sieve connections and other specialised pores are discussed.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: F B
authors.initials: FB
authors.lastname: Wooding