Re: [IAWA Forum] Re: Radial water transport

From: "Graeme Berlyn (FO)" <graeme.berlyn@yale.edu>
Subject: Re: [IAWA Forum] Re: Radial water transport
Date: Tue, 8 Oct 2002 13:27:40 -0400 (EDT)

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While intercellular spaces are small in typical pine wood they are
considerably larger in compression wood. Certain species like Juniperus
virginiana have large intercellular spaces in typical wood due to circular
tracheid cross-section.

In the woods I have observed ray parenchyma and longitudinal parenchyma
are lignified at maturity.

On Mon, 7 Oct 2002 MelTyree@aol.com wrote:

> But I don't think intercellular spaces could contribute much to radial
> transport of liquid water in trees. The intercellular spaces would have to be
> very well isolated from outside air otherwise they would embolize very
> easily. My guess (and this is only a guess) is that intercellular spaces
> would be water filled only from xylem pressure potentials of 0.0 to -0.15MPa.
>
> The accepted interpretation (without lots of proof) is that intercellular
> spaces are a location of stored water and such stored water is mostly gone by
> -0.2 MPa. But while the spaces are filled with water they could contribute to
> radial transport. See Xylem Structure and the Ascent of Sap (Second edition)
> by Tyree & Zimmermann, which is now in print from Springer!
> If you have any photos of intercellular spaces I would be very interested in
> having copies. I think we need more research on this topic.
> The story about ray cells NOT being lignified is interesting to me. Does
> anyone have any citations for that?
> Thanks,
> Mel
>
> Melvin T. Tyree
> Project Leader NE4103
> USDA Forest Service
> Aiken Forestry Sciences Lab
> 705 Spear St  PO Box 968
> Burlington VT 05402
> Phone 802 951 6771 x 1310
> FAX 802 951 6368
>

Graeme Pierce Berlyn, Ph.D.
Professor of Anatomy and Physiology of Trees
Editor, Journal of Sustainable Forestry
------------------------------------------
Yale School of Forestry and Environmental Studies
Greeley Memorial Laboratory
370 Prospect Street
New Haven, CT 06511 USA
Phone: (203) 432-5142
Fax: (203) 432-3929

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