Abstract
Ultrastructural changes in isolated and in situ plasma membranes of etiolated soybean hypocotyls (Glycine max L. cv. Wayne) were induced by indole-3-acetic acid (IAA), other auxins, and calcium chloride. Fixed and embedded preparations were stained by a phosphotungstate-chromate procedure to identify and accentuate plasma membrane. Measurements were on micrographs obtained with an electron optical system calibrated and corrected for reproducible and accurate size measurements. Plasma membranes treated for 20 minutes with 1 μm IAA were 10 to 15% thinner than controls. The response to IAA was rapid, reproducible, auxin-specific, temperature-dependent, and reversible. Comparable responses were obtained with isolated and in situ membranes. Membranes treated with 0.5 m calcium chloride for 20 minutes were 15 to 20% thicker than controls. Multiple cycles of alternating calcium and IAA treatments yielded membranes with dimensions that reflected the last treatment of the series. The findings show a direct response of plasma membranes to growth regulating agents and provide evidence for a cell-free response of isolated plasma membranes to a hormone.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Barkley G. M., Evans M. L. Timing of the auxin response in etiolated pea stem sections. Plant Physiol. 1970 Feb;45(2):143–147. doi: 10.1104/pp.45.2.143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans M. L., Ray P. M. Timing of the auxin response in coleoptiles and its implications regarding auxin action. J Gen Physiol. 1969 Jan;53(1):1–20. doi: 10.1085/jgp.53.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hardin J. W., Cherry J. H., Morré D. J., Lembi C. A. Enhancement of RNA polymerase activity by a factor released by auxin from plasma membrane. Proc Natl Acad Sci U S A. 1972 Nov;69(11):3146–3150. doi: 10.1073/pnas.69.11.3146. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Helgerson S. L., Cramer W. A., Morré D. J. Evidence for an increase in microviscosity of plasma membranes from soybean hypocotyls induced by the plant hormone, indole-3-acetic Acid. Plant Physiol. 1976 Oct;58(4):548–551. doi: 10.1104/pp.58.4.548. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Key J. L. Ribonucleic Acid and Protein Synthesis as Essential Processes for Cell Elongation. Plant Physiol. 1964 May;39(3):365–370. doi: 10.1104/pp.39.3.365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Noodén L. D., Thimann K. V. EVIDENCE FOR A REQUIREMENT FOR PROTEIN SYNTHESIS FOR AUXIN-INDUCED CELL ENLARGEMENT. Proc Natl Acad Sci U S A. 1963 Aug;50(2):194–200. doi: 10.1073/pnas.50.2.194. [DOI] [PMC free article] [PubMed] [Google Scholar]
- REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rayle D. L., Haughton P. M., Cleland R. An in vitro system that simulates plant cell extension growth. Proc Natl Acad Sci U S A. 1970 Dec;67(4):1814–1817. doi: 10.1073/pnas.67.4.1814. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roland J. C., Lembi C. A., Morré D. J. Phosphotungstic acid-chromic acid as a selective electron-dense stain for plasma membranes of plant cells. Stain Technol. 1972 Jul;47(4):195–200. doi: 10.3109/10520297209116484. [DOI] [PubMed] [Google Scholar]
- Wheeler H., Baker B. L. Ultrastructure of thick membranes in plant roots exposed to uranyl and calcium salts. J Ultrastruct Res. 1973 Jun;43(5):355–361. doi: 10.1016/s0022-5320(73)90014-2. [DOI] [PubMed] [Google Scholar]