Atmospheric H2S as sulphur source for Brassica oleracea: Consequences for the activity of the enzymes of the assimilatory sulphate reduction pathway
2001
Westerman, S. ((University of Groningen (Pays-Bas). Laboratory of Plant Physiology)) | Stulen, I. | Suter, M. | Brunold, C. | De Kok, L.J.
Short-term exposure of Brassica oleracea L. (curly kale) to atmospheric H2S levels (0.2-0.8 microL/L), which are sufficient to meet the plants sulphur requirement, resulted in a decrease in the activity of adenosine 5'-phosphosulphate reductase (APR) in the shoot. The reduction in APR activity was maximally 80 / and was already substantial after 1 d exposure to 0.2 microL/L H2S. The activity of APR in the roots remained unaffected upon exposure to all levels of H2S. The activities of ATP-sulphurylase (ATPS), serine acetyltransferase (SAT) and O-acetylserine(thiol)lyase (OAS-TL), in both shoot and roots were not affected upon exposure to H2S levels ranging from 0.2-0.8 microL/L. There was a rapid increase in the shoot thiol content, including cysteine, upon H2S exposure and a maximal 3-fold increase in thiol content occurred after 5 h exposure. In the roots, the thiol content was only slightly increased after 2 d H2S exposure. The relationship between the pattern of thiol accumulation and changes in sulphate assimilation upon H2S exposure is discussed
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