Protoplasma

, Volume 167, Issue 3, pp 215–230

Ultrastructure of freeze-substituted pollen tubes ofLilium longiflorum

Authors

  • Susan A. Lancelle
    • Botany DepartmentUniversity of Massachusetts
  • P. K. Hepler
    • Botany DepartmentUniversity of Massachusetts
Article

DOI: 10.1007/BF01403385

Cite this article as:
Lancelle, S.A. & Hepler, P.K. Protoplasma (1992) 167: 215. doi:10.1007/BF01403385

Summary

In view of the importance of the lily pollen tube as an experimental model and the improvements in ultrastructural detail that can now be attained by the use of rapid freeze fixation and freeze substitution (RF-FS), we have reexamined the ultrastructure of these cells in material prepared by RF-FS. Several previously unreported details have been revealed: (1) the cytoplasm is organized into axial “slow” and “fast” lanes, each with a distinct structure; (2) long, straight microtubule (MT) and microfilament (MF) bundles occur in the cytoplasm of the fast lanes and are coaligned with every organelle present; (3) the cortical cytoplasm contains complexes of coaligned MTs, MFs, and endoplasmic reticulum (ER); (4) the cortical ER is arranged in a tight hexagonal pattern and individual elements are closely appressed to the plasma membrane with no space between; (5) mitochondria and ER extend into the extreme apex along the flanks of the pollen tube, and vesicles and ER are packed into an inverted cone-shaped area at the center of the apex; (6) MF bundles in the tip region are fewer, finer, and in random orientation in comparison to those of the fast lanes; (7) the generative cell (GC) cell wall complex contains patches of plasmodesmata; (8) The GC cytoplasm contains groups of spiny vesicles that are closely associated with and seem to be fusing with or pinching off from mitochondria, and (9) the vegetative nucleus (VN) contains internal MT-like structures as well as numerous cytoplasmic MTs associated with its membrane and also located between the VN and GC.

Keywords

LiliumFreeze substitutionPollen tubesRapid freeze fixationUltrastructure

Abbrevations

CF

chemical fixation

ER

endoplasmic reticulum

GC

generative cell

MF

microfilament

MT

microtubule

PD

plasmodesmata

PM

plasma membrane

RF-FS

rapid freeze fixation-freeze substitution

VN

vegetative nucleus

Copyright information

© Springer-Verlag 1992