| TITLE |
Effect of tonicity and additives to the fixative on ultrastructure of mesophyllous cells in Kandelia candel (L.) Druce (Rhizophoraceae) |
| AUTHOR |
Yuan-Hsun Hwang
Institute of Botany, Academia Sinica, Taipei, Taiwan 115, Republic of China
Shuh-Chun Chen
Institute of Botany, Academia Sinica, Taipei, Taiwan 115, Republic of China |
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| ABSTRACT |
We investigated the effect of tonicity and additives to the fixative on the ultrastructure of Kandelia candel. Nonionic additives such as sucrose were better than ionic additives such as NaCl, KCl, Na2SO4 or K2SO4. Measurement of osmolality in the K. candel cells was carried out for adjusting the osmolality of the fixatives. We found that the hypertonic fixative and the washing buffer obtained by adding 0.15 M sucrose to the isotonic fixative and 0.1 M phosphate buffer yielded the best results; outer membranes of chloroplasts and mitochondria did not dilate or undergo plasmolysis. Varying the tonicity of the fixative with sucrose to a reasonable degree did not change the ultrastructural details within the chloroplasts and mitochondria. In contrast, hypertonic fixatives obtained by adding ionic additives caused significant swelling of thylakoid membranes in chloroplasts. This artifact was most pronounced when hypertonic fixatives containing NaCl or KCl were used. These observations suggest that high ionic fixatives disturb the ionic balance in thylakoid membranes. |
| KEYWORD |
Kandelia candel; Mangrove; Osmotic potential; Salt; Sucrose; Tonicity; |
| ARTICLE INFO |
Botanical Bulletin of Academia Sinica, Volume 38 Number 1 January 1997, page 21-28, 8 pages |
| PUBLISHER |
Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China |
