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Mikroanalytische Identifikation von Bariumsulfat-Kristallen in den Statolithen der Rhizoide von Chara fragilis, Desv.
Klaus Schröter, André Läuchli and Andreas Sievers
Vol. 122, No. 3 (1975), pp. 213-225
Published by: Springer
Stable URL: http://www.jstor.org/stable/23371206
Page Count: 13
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In contrast to the statocytes of higher plants, in which amyloplasts function as statoliths, Chara-rhizoids contain statolith vacuoles filled with biocrystallites of BaSO4. This was revealed by qualitative and quantitative electron microprobe analysis, atomic absorption spectrophotometry and selected area electron diffraction. The barium sulphate crystallites are rods which are linearly composed of globular subunits approximately 7 nm in diameter. The electron optical evidence of the crystallites depends on the nature of the fixatives. Best structural preservation was observed after fixation in a buffered solution of glutaraldehyde plus acrolein without addition of heavy metals. OsO4 and particularly KMnO4 partially dissolve the biocrystallites as well as synthetic BaSO4. The crystal solubility must be taken into consideration when micrographs of such small crystallites are interpreted. The fact that BaSO4 is chemically very inert seems to exclude biochemical interactions of the statoliths with other cell components during graviperception. It favours the theory that only the mass of the statoliths is effective.
Planta © 1975 Springer