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  Contractile roots
From: Mike Bordelon <BORDELON.MIKE at NMNH.SI.EDU> on 1997.09.03 at 16:28:58(1155)
Hello everybody,
A recent discussion on AEG about contractile roots on
Arisaemas prompted this question. I dug Amorphophallus
muelleri from a bed yesterday and they appeared to be at the
same depth of planting. I know they have roots that emerge
from the top to stabilize the plant, but do Amorphophallus
also have contractile roots to pull them further into the soil ?

Mike Bordelon

From: "Don Bittel" <dbittel at treco.net> on 1997.09.08 at 06:13:01(1182)
Mike,
My theory is that Amorphophallus do not have contractile roots. Instead,
the rotting away of the old tuber allows the new tuber to 'fall' into the
hole that is left, thus lowering the tuber deeper each time. This allows it
to stabilize itself better as it grows larger and larger. I have noticed
this on all of my species when I used to dig them up every winter. They got
so deep that now I just leave them in the ground. In this part of Florida
we rarely get a hard freeze anyway. There must be some stopping point to
this, however, or it could eventually sink down to the water table and rot
away! I would be happy to hear from Wilbert or anyone else on this subject
also.

+More
From: Wilbert Hetterscheid <hetter at vkc.nl> on 1997.09.08 at 09:03:22(1187)
Don Bittel's answer to Mike Bordelon's question has one flaw.
Amorphophallus DO have contractile roots. Just have a look at older
roots at the top of the tuber when you take one out. It is especially
noticeable on larger plants. The "drop in the hole" idea will certainly
be true but without the contractile roots, the whole structure would
tumble to its side for lack of anchorage.

Wilbert

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From: Rand Nicholson <writserv at nbnet.nb.ca> on 1997.09.08 at 12:37:10(1189)
>Don Bittel's answer to Mike Bordelon's question has one flaw.
>Amorphophallus DO have contractile roots. Just have a look at older
>roots at the top of the tuber when you take one out. It is especially
>noticeable on larger plants. The "drop in the hole" idea will certainly
>be true but without the contractile roots, the whole structure would
>tumble to its side for lack of anchorage.
>
>Wilbert

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From: MJ Hatfield <oneota at ames.net> on 1997.09.09 at 05:57:08(1191)
Wilbert said "contractile roots. Just have a look at older
roots at the top of the tuber when you take one out."
Please enlighten me. I don't know what a contractile root looks like.
Thanks.
MJ Hatfield

From: Wilbert Hetterscheid <hetter at vkc.nl> on 1997.09.09 at 06:10:13(1193)
Rand,

Yes, it would indeed grow in the old cavity which is in line with what
Don Bittel said. But there is always that moment when there is less
tuber than cavity at which time the plant needs to be anchored or it
would become unstable. I have seen this in my own collection and it is
known from plants in the wild: if you dig them out when the leaf has
just emerged, you may not find a shred of tuber and the petiole is kept
in place by the horizontal contractile roots and the soil surrounding
the base of it.

Cheers,
Wilbert

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From: Krzysztof Kozminski <kk at netgate.net> on 1997.09.09 at 14:01:23(1201)
On Tue, 9 Sep 1997, MJ Hatfield wrote:

> Wilbert said "contractile roots. Just have a look at older
> roots at the top of the tuber when you take one out."
> Please enlighten me. I don't know what a contractile root looks like.
> Thanks.

See

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From: Roger Sieloff ISDH <sieloff at doe.state.in.us> on 1997.09.09 at 21:03:45(1210)
On Tue, 9 Sep 1997, MJ Hatfield wrote:

> Wilbert said "contractile roots. Just have a look at older
> roots at the top of the tuber when you take one out."
> Please enlighten me. I don't know what a contractile root looks like.
> Thanks.
> MJ Hatfield

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From: Wilbert Hetterscheid <hetter at vkc.nl> on 1997.09.10 at 09:14:49(1211)
Mary Jane,

A contractile root looks like an ordinary root but the "skin" is heavily
wrinkled as if pushed up from one side over the inner tissues. Does that
make sense?

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From: MJ Hatfield <oneota at ames.net> on 1997.09.11 at 07:08:32(1222)
Yes, I now understand contractile roots. Yesterday I dug up both an
Amorphophallus and an Arisaema to look at the roots (they were ready to
be dug anyway, I think). Do Arisaema have contractile roots too? Both
species seemed to have them.
Another surprise. I was crawling around looking at the plants in my
aroid bed and there, next to the ground, was a Sauromatum seed head with
what look like immature but fertile seeds. I know they bloomed after
being planted outside but I didn't know I had the proper pollinators. I
guess so. (Not quite as striking as the seed head of my A.konjac last
year.)
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From: hallsa at sirius.com (Steve Hall) on 1997.09.11 at 09:44:36(1226)
>Another surprise. I was crawling around looking at the plants in my
>aroid bed and there, next to the ground, was a Sauromatum seed head with
>what look like immature but fertile seeds.

Much to my surprise, two of my Sauromatum produced seed heads this year.
Can any one give me some advice on how to harvest these seeds?

Steve Hall

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