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Cyanide Seeds -

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Following their discovery of a master molecule in smoke which causes seeds of many Australian
native plants to germinate, Australian researchers observed that the West Australian Kangaroo Paw
doesn't germinate in response to the master molecule - so what does it respond to? Tanya Ha learns
how, for Kangaroo Paw at least, smoke contributes to the release of a life giving substance -
cyanide!

Excerpt from film "And then there were none"

Man

Chokes.

Woman

How perfectly disgusting.

Tanya Ha

We generally think of cyanide as a killer rather than a creator of life. But in this distinctly
Western Australian tale

be prepared for the unexpected.

NARRATION

Bushfires can be incredibly destructive. But they also play a positive role in the Australian
landscape.

Dr. Kingsley Dixon

The Australian bush has a remarkable ability to cope with bushfires.//

Fire is one of the great regenerators that restarts eco systems, begins the germination process,
helps species to bloom. Of course the great mystery is what is locked in bushfire smoke that is the
key agent that does this remarkable stimulation.

NARRATION

Professor Kingsley Dixon together with his colleague Dr Gavin Flematti thought they'd solved this
mystery some years ago.

Dr. Kingsley Dixon

Ah here you go, these are our beautiful little sundews

Dr Gavin Flematti

So that won't flower unless there's been a fire. No. You get zero.

Dr. Kingsley Dixon

In 2004 we made the discovery that there was a master molecule locked in bushfire smoke that
stimulated the germination of a whole variety of Australian species.

NARRATION

They named the molecule karrikinolide after a local Aboriginal word, karrik, meaning smoke.

Dr Gavin Flematti

Karrikinolide was a new compound to science it hadn't been described before. So one of the
difficulties was to prove that it was the structure we proposed which we were able to achieve.

Tanya Ha

But not long after their discovery and much to their surprise, Kinglsey and Gavin realised that
this iconic WA plant, the Kangaroo Paw wasn't germinating in response to karrikinolide, what was
going on?

Dr. Kingsley Dixon

We were almost in disbelief that the master molecule didn't work with this species because it grew
in a bush land environment that had a whole mixture of species that did respond to that master
molecule

Tanya Ha

So if it wasn't karrikinolide on its own that was germinating kangaroo paw seeds how did you know
it was something else in the smoke mixture?

Dr. Kingsley Dixon

Ah because we could germinate a full range of species with smoke and with that we'd get complete
germination. Smoke is the most complex natural mixture of compounds that occurs on the planet.

Tanya Ha

So obviously not germinated yet.

Dr. Kingsley Dixon

No a couple of weeks and we should start to see the first emergence coming out. Without the smoke
you won't get those species coming up at all.

NARRATION

Knowing that the suspect was somewhere in the smoke, the hunt returned to the lab.

Dr Gavin Flematti

And it was known that when you bubble smoke through water you can trap the germination active
compounds in that water.

Smoke contains over four thousand different compounds so it's a very difficult task in separating
all those compounds out t look for the active compound that's responsible for this effect. We get
essentially a clear solution that we can then test on the kangaroo paw seeds

Tanya Ha

After five years of carefully sifting through the smoke they finally discovered what makes kangaroo
paw germinate after bush fires.

NARRATION

The culprit was the compound glyceronitrile.

Dr Gavin Flematti

It turned out to be a known compound so it was a little bit disappointing in that regard. It turned
out to be quite fascinating the way you know it can release cyanide and that cyanide was the true
active stimulant in this case.

Dr. Kingsley Dixon

Cyanide's been known to germinate a range of species all the way from sunflowers to apple seeds.
But it's only ever been shown in laboratory situations to have that role. it's a first for science
that we've discovered that there is a natural ecological source for cyanide.

The molecule that's produced from bushfire smoke percolates through the soil, enters the seed with
that first flush of winter rainfall, and then the cyanide is released inside the seed and it's then
cyanide does the work. The discovery of cyanide really has just opened our eyes that Australia is
the continent of discovery. Every story that we start unravelling here becomes essentially a new
book on the way that plants have adapted to live on the planet.

Tanya Ha

So Kingsley's work continues. But in the meantime it's good to know that cyanide is useful for
something other than removing an inconvenient relative.