Changes in the DNA lesions induced by alkylating agents during the post-treatment washing and redrying of barley seeds

Abstract

During the 24 hours’ washing of14C MNU and14C MMS-treated seeds the amount of DNA 7-methylguanine as well as the total alkylation of DNA, RNA and proteins in cells of the embryo was enhanced. The drying of shortly washed14C MNU-treated seeds to 30% and 15% water content led to, a similar increase of alkylation. In accordance with the changes in the biological damage, the amount of single strand breaks and/or alkali labile sites in DNA dropped down during a 19 h washing period of MNU-treated seeds but changed only slightly in MMS-treated and 19 hours washed seeds. The drying of 0·5 or 18 h resp. 19 h washed seeds treated either with MNU or MMS to 15 per cent water content increased the amount of single strand breaks and/or alkali labile sites in DNA.