cyanide and seed germination

Henry Kuska has brought up a very interesting point about seed germination. Cyanide (CN) is produced by all plants simultaneously with ethylene, as part of the reaction that makes ethylene. Until recently this CN has been more or less ignored. There is an enzyme that quickly reacts it with an amino acid (Cysteine or serine maybe)to make another amino acid eventually giving asparagine, a very common amino acid. So all plants are able to detoxify some CN. We have been studying how they are able to do so in the field, as a way to clean up Cn from mining etc. But the important point for seed germination is that CN may act in parallel to ethylene in ways that ahve been ignored in the past.

Also, some plants accumulate compounds called cyanogenic glycosides, which release CN when the plant is injured, usually by something trying to eat it. This can deter insects and even mammals from eating the plant or seed. Peach pits, cherry stones, apple seeds all have a lot of CN stored in this way. Maybe rose seeds do too, they are part of the same plant family.

Perhaps when degradative enzymes attack the seed it releases some cyanogenic glycoside which then releases some CN which stimulates the seed to start germinating before it gets rotted away completely. Stratification may be to some extent rotting the seed, at least its tough outer coat, and releasing enough CN to trigger the germination process. Now we need to find a safe way to add CN to the seeds. Cyanogenic glycosides give you CN without ethylene, a very interesting possiblity.

Nitric oxide, NO, is made directly from arginine so it woudl be reasonable that arg can stimulate NO production, if the necessary enzyme is there. NO binds to certain enzymes by way of their heme and activates them. CN might bind in place of NO in some cases because as Henry suggests, NO and CN have a lot in common in some ways. Not much is known of the way that NO sends signals in plants. Most of the work is done in animals but it is likely to be similar given that it is a very ancient process.

Hi Larry, I haven’t read into cyanide production or pathwys in seeds but so many questions spring to mind…

Does cyanide inhibit fungal growth? Maybe the cyanide inhibits fungal growth in some seeds (maybe it can be selected for) long enough to allow germination to occur. Do all seeds produce the same level of cyanide? Some seeds seem to develop fungus no matter what you do to try and prevent it… Is cyanide an alleopathic substance? Maybe it is designed to leach into the surrounding soil to inhibit the growth of seedlings around it to reduce competition for resources… if this is true maybe spacing the seeds out more will increase germination rates.

Found these and thought they might be intersting:

"Effect of Hydrogen Cyanide and Carbonyl Sulphide on the Germination and Plumule Vigour of Wheat

(http://www3.interscience.wiley.com/cgi-bin/abstract/16644/ABSTRACT?CRETRY=1&SRETRY=0)

Several factors which may influence the germination of wheat fumigated with hydrogen cyanide or carbonyl sulphide were investigated. Dosages of hydrogen cyanide ranged from 10 mg litre-1 for 24-h exposure up to 150 mg litre-1 for 96-h exposure. Dosages of carbonyl sulphide ranged from 25 mg litre-1 for 24-h exposure up to 500 mg litre-1 for 72-h exposure. The experiments were conducted on wheat of 11

hello

I was very pleased I read your article.

Please send me your procedure.

Of course, if possible.

thanks.