ATTEMPTS TO SYNCHRONISE SEED GERMINATION

Individual seeds within a population hardly ever germinate simultaneously.
The desired synchronisation can in many cases be achieved by seed ‘priming’: seeds are made to imbibe aerobically under conditions which permit them to pass through the preparatory stages of germination but which prevent the completion of the process by interposing a physiological barrier to radicle emergence.
Temperature, water potential and duration of the treatment can all affect the result, and different species (even seed lots) may require different treatments for the best effects.
Ideally, synchronised, early and full germination can result but a given treatment does not necessarily achieve all these three objectives equally well.
Treated seeds can be sown with a conventional seed drill, either after surface drying or after storage in the air dry state, but different species respond very differently to air drying.
Some (e.g. carrot, parsley, parsnip) lose little or nothing, but others lose much of the benefit from the treatment.
One of the most problematic subjects in this respect is celery (at least cv.
Lathom Blanching) and here the treatment method, especially the duration, is more critical for seeds which are to be dried back than for those only to be surface dried.
Thus, for seeds to be dried back, 7 or 14 days’ treatment can lead to considerably better results than 10 days’ treatment.

With most subjects the best results have been achieved by using hypertonic solutions which can be generated by the inert osmoticum, polyethylene glycol ‘6000’, and the most useful treatments have ranged from 7 to 21 days’ exposure to -10 to -15 bars water potential at 10 to 20°C.

Symposium on the Timing of Field vegetable Production

W. Heydecker, Beryl M. Gibbins

https://doi.org/10.17660/ActaHortic.1978.72.8