Re: frozen plants
- To: s*@MAELSTROM.STJOHNS.EDU
- Subject: Re: [SG] frozen plants
- From: M* T*
- Date: Mon, 17 Jan 2000 00:25:34 -0500
Lovely post, Jim....and, oddly enough the subject of my latest
article:-) Find this acclimation ability in plants totally
fascinating. The part that is really interesting is that different
parts of the same plant will be programmed to withstand different
degrees of frost and, from my research on the subject, it appears
that just why this is so is not yet fully understood.
It appears that roots and flower buds have less ability to withstand
frost than stems and vegetative buds. I can understand a plant being
willing to sacrifice flower and fruit for life, but would think that
roots were pretty important in their outlook and ought to be the most
frost resistant. Perhaps it is because plants assume their roots are
supposed to be protected by the earth? Whatever....it's the reason
that hardy plants who are frost-heaved will die if not stuck back in
the ground soon enough...
Another fascinating factoid that I learned researching this article
is that transgenic plants are being developed, where the genes
responsible for cold hardiness in one plant are inserted into the
genetic material of another to increase the latter's hardiness...even
found a site with a little video illustrating this process. Seems a
great amount of research is being done - primarily on crop plants -
towards these ends.
The world of molecular botany is mostly beyond my grasp, but the
parts that I can understand are rather mind blowing. Plants are
complex creatures who do rather fabulous things in the course of
their daily lives, quite beyond sating our gardener's lust with
flowers and foliage and providing food (in one way or another) for
most other living things.
Marge Talt, zone 7 Maryland
mtalt@clark.net
Editor: Gardening in Shade
current article:Acclimation - Why Did My Plant Die? Redux
http://suite101.com/welcome.cfm/222
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----------
> From: J.E. Shields <jshields@INDY.NET>
> Date: Sunday, January 16, 2000 6:39 PM
>
> Plants which cannot resist freezing temperatures die because ice
crystals
> from inside their tissues, and the crystals pierce the cell walls.
When
> the ice melts, the cells loose their contents.
>
> So why don't all plant cells just up and die when temperatures drop
below
> freezing?
>
> Basically, like everything else about plants and animals, it all
goes back
> to their genes. Plants which can resist freezing temperatures have
genes
> which produce substances that protect against freezing. These may
act in
> any of several ways. Some of them can change the plant's
metabolism to
> produce extra sugars or glycerol inside the cells, lowering the
cell's
> interior freezing point.
>
> Other substances act more directly, by preventing the ice crystals
which
> may start to form, from growing large enough to break the cell
walls.
>
> The more of these protective substances that the plant's genes
direct to be
> formed, the more freezing the plant can withstand.
>
> Jim
>
> *************************************************
> Jim Shields USDA Zone 5 Shields Gardens, Ltd.
> P.O. Box 92 WWW:
http://a1.com/daylily/
> Westfield, Indiana 46074, USA Tel.
+1-317-896-3925
