Message-Id: <v01510101b023611dc041@[205.134.246.15]>
Date: Fri, 22 Aug 1997 07:42:51 -0800
To: pinhole@exploratorium.edu
From: bcomet@sirius.com (Burt C. Kessler)
Subject: Re: Plant Growth
>Two questions for the Botanists in the Pinhole crowd:
>1. How is it (physiologically speaking) that some plants are able to grow
>roots from clippings? I realize that commerically available plant root
>growth hormones are able to artificially induce this in most plants, so
>hormones must play a role in the natural process. But does anyone have a
>more exact description (i.e. what structure initiates the growth)?
>2. What plant families are able to grow naturally from clippings?
>Thanks for the consideration.
>
>------------
>Joey Stewart
>jstewart@marin.k12.ca.us
I can't say which plant families allow propagation from cuttings, however
in regards to the process:
Cutting the stem injures the cells. Healing occurs initially to prevent
loss of fluids. The cells formed to heal the wound are relatively
undifferentiated parenchyma cells known as a "callous". Under the correct
conditions, callous cells can differentiate into almost any cell type.
Hormones speed up (and also direct?) the differentiation. Propagation by
cutting is more successful if the cutting is allowed to form the callous.
This can be accomplished by allowing the end of the cutting to dry out for
a day or so before planting. If the cutting is immediately planted some
percentage of cuttings will rot rather than grow roots as fungi enter the
stem unprotected by a callous.
Burt C. Kessler
bcomet@sirius.com
The easy way out usually leads back in.