The role of calcium ions in phytochrome-controlled swelling of etiolated wheat (Triticum aestivumL.) protoplasts
✍ Scribed by Margreet E. Bossen; Hans H. A. Dassen; Richard E. Kendrick; Willem J. Vredenberg
- Publisher
- Springer-Verlag
- Year
- 1988
- Tongue
- English
- Weight
- 765 KB
- Volume
- 174
- Category
- Article
- ISSN
- 0032-0935
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✦ Synopsis
Protoplasts from dark-grown wheat (Triticum aestivum L.) maintained at a constant osmotic potential at 22°C, were found to swell upon red irradiation (R) and the effect was negated by subsequent far-red light (FR), indicating phytochrome involvement. Swelling only occurred when Ca(2+) ions were present in the surrounding medium, or were added within 10 min after R. Furthermore, Mg(2+), Ba(2+) or K(+) could not replace this requirement for Ca(2+). The presence of K(+) did not enhance the Ca(2+)-dependent swelling response. When the Ca(2+)-ionophore A 23187 was added to the medium, protoplasts swelled in the dark to the same extent as after R. Both the Ca(2+)-channelblocker Verapamil and La(3+) inhibited R-induced swelling. It is proposed that R causes the opening of Ca(2+)-channels in the plasma membrane. Boyle-van't Hoff analyses of protoplast volume after R and FR are consistent with the conclusion that R irradiation causes changes in membrane properties.