Delayed luminescence and priming-induced nuclear replication of unaged andcontrolled deteriorated pepper seeds (Capsicum annuum L.)

Unaged and controlled deteriorated seeds (45 degrees C for 4 and 6 days) we re subjected to osmoconditioning in PEG (polyethylene glycol) at an osmotic potential of -1.5 MPa for 6 and 12 days. In unaged seeds both priming trea tments induced nuclei of the embryo root rips to enter the DNA synthetic ph ase, although to different extents. Osmoconditioning of controlled deterior ated seeds induced nuclear replication activity only when performed for the longest duration. In accordance with our previous findings, the frequency of nuclei induced to enter the synthetic phase was directly correlated with the improved seed germination performance, as measured by reduction in the mean time to germination. However, the frequency of priming-induced DNA sy nthesis cannot be used by itself to predict the efficiency of a seed primin g treatment when pel formed on deteriorated seeds. With the objective of id entifying new parameters for seed vigour estimation, variation in delayed l uminescence (i.e. the light emitted a few milliseconds after the illuminati on stimulus has been switched off) emitted by unaged, aged and osmoprimed s eeds has been analysed. A correlation between total photoinduced delayed lu minescence and seed germination performance was observed, suggesting the po ssibility of using this parameter as a non-invasive method in order to test the physiological state of a seed sample.