Seed Germination - The University of Reading Method

(The 'Reading' Method)

Dr James Ross reported most interesting results from the University of Reading project on cyclamen seed germination on behalf of the Society. Samples of C. coum and C graecum supplied in December 1991 and October 1992 were used in an attempt to establish a successful procedure for rapid and uniform germination. Upon reception, and prior to use, these seed batches were dry-stored in metal cans at 5°C (41°F).

Initially, experiments were carried out on filter papers in plastic petri dishes in order that imbibition solutions could be changed easily and any germination easily monitored. Once a possibly useful regime was established a procedure more useful to the grower was investigated. The most important finding was the necessity of getting it right first time; failure to do so lead to a protracted and erratic germination schedule which was most unsatisfactory.

The primary requirements for successful germination were shown to be the absence of light, an adequate temperature (15-20°C, 59-68°F) and a constant water supply. Any deviation from this regime seemed to bring about the onset of a deep-seated secondary dormancy which could not be alleviated by repetition of the original treatment. In this case only the addition of a gibberellic acid solution seemed to be able to stimulate germination. In a number of other species gibberellin treatment may stimulate germination but successful establishment and seedling growth may be abnormal.

The imposition of a perfectly dark regime for the 15 to 26 days needed while held at the correct temperature (l5°C, 59°F) is purely a technical matter: keeping the soaked seeds in biscuit tins in a kitchen larder would probably suffice. However, the maintenance of an adequate and constant water supply so that the seeds do not dry out even slightly nor are they flooded is more difficult - especially as it is best not to attempt to open the light-tight container. The Reading researchers felt that the use of peat-plugs with their good water-retention properties was the best way to achieve the desired results both for germination and subsequent potting-on.

Using other more granular substrates under nursery conditions could lead to problems. Light could penetrate quite deeply through most soils and even levels not normally perceived by the human eye will induce secondary dormancy. Similarly, minor fluctuations of water content interrupt the process.

The work was carried out by Colin Ellis, a BSc student, under Dr Ross's supervision.