Multiple effects of chromate on Spirodela polyrhiza: Electron microscopy and biochemical investigations

K. J. Appenroth, Á Keresztes, É Sárvári, A. Jaglarz, W. Fischer

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Growth rates of S. polyrhiza were reduced by chromate concentrations higher than 50 μM. Analysis of plant cells by transmission electron microscopy revealed the accumulation of starch grains in the chloroplasts following the application of chromate at low concentrations or for short periods (100 μM for 2 days or 500 μM for 1 day). Increasing the chromate concentration (1000 μM for 1 day) or extending the period (100 μM for 4 days) resulted in the disappearance of most of the starch grains and the extensive formation of plastoglobuli. These results were confirmed by chemical analysis of the starch content. It has been suggested that this transient accumulation of starch was caused, first, by inhibition of the export of carbohydrates out of the plastids, and then by inhibition of photosynthesis. Chromate decreased the chlorophyll content and the chlorophyll a/b ratio. The quantitative analysis of the chlorophyll protein complexes showed that the photosystem II (core complex as well as connecting antenna) was more sensitive to chromate treatment than photosystem I and the peripheral light-harvesting complex of photosystem II. This explains the previous results on time-resolved chlorophyll a fluorescence (Appenroth et al. Environ. Pollut. [2001] 115, 49-64). Photosynthesis is clearly an important target of chromate toxicity. Electron microscopic analysis showed damage to several membrane systems, such as that of thylakoids, chloroplast envelope, plasmalemma and, at higher concentrations, that of tonoplast and mitochondria. Thus, the membrane system is another target of chromate toxicity.

Original languageEnglish
Pages (from-to)315-323
Number of pages9
JournalPlant Biology
Issue number3
Publication statusPublished - May 1 2003



  • Chlorophyll protein complexes
  • Chromate
  • Electron microscopy
  • Growth test
  • Heavy metal toxicity
  • Spirodela polyrhiza

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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