Abstract
RECENT work in this laboratory has confirmed that the pores in the sieve plates of functioning phloem are normally occluded, fairly densely, with slime fibrils. Stems of Helianthus seedlings and thin stolons of Saxifraga sarmentosa were plunged into briskly boiling water for 3 min before conventional fixation in glutaraldehyde and osmium, embedding and sectioning for electron microscopy, In almost all cases, the pores in the sieve plates appeared plugged with densely-staining material (Fig. 1a and b); where this was not obvious the micrographs strongly suggested that the section had passed between the shrunken plug and the pore wall. We regard these observations as evidence against the views often put forward that the plugging is an artefact of preparation caused either by longitudinal turgor release or by local enzyme action1,2.
Similar content being viewed by others
Article PDF
References
Weatherley, P. E., and Johnson, R. P. C., Intern. Rev. Cyt., 24, 149 (1968).
Shih, C. Y., and Currier, H. B., Amer. J. Bot., 56, 464 (1969).
Cronshaw, J., and Esau, K., J. Cell. Biol, 34, 801 (1967).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
SIDDIQUI, A., SPANNER, D. State of the Pores in the Functioning Sieve Plate. Nature 226, 88 (1970). https://doi.org/10.1038/226088a0
Received:
Issue Date:
DOI: https://doi.org/10.1038/226088a0
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.