Specialised Seed Treatments

 

Inevitably, in such a variable process as seed germination, there is still much that is imperfectly understood. There are, evidently, other than ‘normal’ cues which stimulate germination and often appear in unusual or particular environmental situations or geographical locations. There is also the possibility of sidestepping dormancy by the use of chemicals.

 

1. Promotion of germination by the use of ‘chemicals’

 

a) Giberellic Acid is a known growth promoter and it is not unreasonably postulated that it is the material which promotes seed germination. As any inhibitor present is eliminated there is an increase in Giberellic Acid - ie GA increases as ABA is reduced.

 

Hence it would be reasonable to suppose that a GA soak might enhance germination by overcoming such dormancy issues. The picture is complicated by the number of varieties of GAs which occur in plants, GA3 – commonest used.

 

b) Other chemical treatments which have been shown to be effective in promoting germination in particular circumstances are:- soaks with (inter alia) Kinetin and Potassium nitrate.

 

2. Promotion of germination by the ‘by products’ of fire

 

As germination is potentially stimulated or cued by fire in those plants from ‘fire ecology’ environments it is logical to assess the impact of fire. Primarily the effect is usually simply one of heat degrading an impermeable seed coat by one of the many processes available. Secondarily the effect may be by the action of the chemical residues of fire – ie ‘smoke’, ‘charate’.

 

[Burn dry woody and green material from the species or related plants in a drum and pipe the smoke into a plastic tent containing the sown seeds, leave in situ for a couple of hours ie a ‘smoke’ treatment – or burn related woody material on top of a sown seed container (not plastic – it will probably melt!) and then place under mist or similar and allow the ‘charate’ to be leached into the compost and, hence, the seed.

 

It is now possible buy ‘discs’ of extract which are placed in water and the water then used to soak (imbibe) the seeds.

 

3. Australian provenance

 

There are many genera of Australian plants which can prove difficult to germinate and which do not respond to the ‘normal’ or ‘conventional’ approaches to the issue. Perhaps this is not surprising as the continent has been isolated for so long that alternative solutions to the development of dormancy have been evolved.

 

 

All of the above treatments are in a state of flux as researchers around the world delve into these mysteries. It therefore behoves the practitioner to investigate via the internet the current position.