Abstract.
Brassica napus L. (oilseed rape) was grown from seeds on a reconstituted soil contaminated with cadmium (100 mg Cd kg−1 dry soil), resulting in a marked chlorosis of the leaves which was investigated using a combination of biochemical, biophysical and physiological methods. Spectroscopic and chromatographic analyses of the photosynthetic pigments indicated that chlorosis was not due to a direct interaction of Cd with the chlorophyll biosynthesis pathway. In addition, mineral deficiency and oxidative stress were apparently not involved in the pigment loss. Leaf chlorosis was attributable to a marked decrease in the chloroplast density caused by a reduction in the number of chloroplasts per cell and a change in cell size, suggesting that Cd interfered with chloroplast replication and cell division. Relatively little Cd was found in the chloroplasts and the properties of the photosynthetic apparatus (electron transport, protein composition, chlorophyll antenna size, chloroplast ultrastructure) were not affected appreciably in plants grown on Cd-polluted soil. Depth profiling of photosynthetic pigments by phase-resolved photoacoustic spectroscopy revealed that the Cd-induced decrease in pigment content was very pronounced at the leaf surface (stomatal guard cells) compared to the leaf interior (mesophyll). This observation was consistent with light transmission and fluorescence microscopy analyses, which revealed that stomata density in the epidermis was noticeably reduced in Cd-exposed leaves. Concomitantly, the stomatal conductance estimated from gas-exchange measurements was strongly reduced with Cd. When plants were grown in a high-CO2 atmosphere (4,000 μl CO2 l−1), the inhibitory effect of Cd on growth was not cancelled, suggesting that the reduced availability of CO2 at the chloroplast level associated with the low stomatal conductance was not the main component of Cd toxicity in oilseed rape.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Author information
Authors and Affiliations
Additional information
Received: 14 July 2000 / Accepted: 27 August 2000
Rights and permissions
About this article
Cite this article
Baryla, A., Carrier, P., Franck, F. et al. Leaf chlorosis in oilseed rape plants (Brassica napus) grown on cadmium-polluted soil: causes and consequences for photosynthesis and growth. Planta 212, 696–709 (2001). https://doi.org/10.1007/s004250000439
Issue Date:
DOI: https://doi.org/10.1007/s004250000439