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.