questions?

From: xylem@unity.ncsu.edu
Subject: questions?
Date: Mon, 07 Oct 2002 15:30:00 -500

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just some queries about intercellular spaces and unlignified 
paraenchyma 

In Wetmore's paper (in 1930s or 1950s? - havent' found reference yet) on 
intercellular spaces in trees (emphasis on gas exchange and lenticels) 
did he have information on the occurrence of intercellular spaces?   
Bolton, et al. 1975 IAWA Bull. 171 2: 3-12 reviewed interstitial spaces  -- 
mostly in Araucariaceae.

are there usually / always longitudinal interstitial spaces in the woods that 
have radial interstitial spaces?   or are radial intercellular spaces more 
common?  How big of a volume does the system  of intercellular spaces 
represent, is there some way of using serial tangential sections and 
image analysis to estimate the volume?   -- and are there always blind 
pits from the parenchyma into the intercellular spaces? [see Panshin & 
deZeeuw 4th ed. p. 124]? 

Re unlignified parenchyma -- probably Carlquist's 1991 paper has 
information on unlignifed parenchyma in vines.  

see Panshin & DeZeeuw 4th edition, p. 151 re lignification of ray 
parenchyma cells being delayed in some pines.  

Carlquist, S. 1991.  Anatomy of vine and liana stems: a review and 
synthesis. Pp 53--71 In: F.E. Putz and H.A. Mooney (eds.), The biology of 
vines, Cambridge University Press, Cambridge.

> Hi,
> Answering Dr. Tyree regarding unlignified rayparenchyma:
> I am currently working with Urera caracasana(a tree) and U. eggersii (a
> liana). Both of them present zones of lignified and unlignified
> parenchyma. The liana has very wide rays, with alternating zones of
> lignified and unlignified parenchyma. This species has a way to secure
> tangential water movement across these wide rays, producing vessels
> which run almost horizontally, comunicating  areas of vessels to both
> sides of the rays. However, we do not have evidence of how this liana
> copes with radial water transport through thes exceptionally wide rays.
> I made resin-casrtings of Urera stems, but unfortunately, parenchyma
> tends to fall appart in individual cells. Only vessels form nice casts.
> By the way, I would appreciate refrences on unlignified parenchyma.
> 
> Guillermo Angeles
> Instituto de Ecología, A.C.
> Depto. de Productos Forestales y Conservación de Bosques
> Km. 2,5 Carretera Antigua  a Coatepec No. 351
> Congregación ?El Haya?
> 91070 Xalapa, Veracruz
> México.
> 
> 
> 
> MelTyree@aol.com ha escrito:
> 
> > 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
> 
> --
> Guillermo Angeles.
> Instituto de Ecología, A.C.
> Depto. de Productos Forestales y Conservación de Bosques
> Km. 2,5 Carretera Antigua  a Coatepec No. 351
> Congregación "El Haya"
> 91070 Xalapa, Veracruz
> México
> 
> Tel. (228) 842 18 35
> Fax  (228) 818 7809
> 
> 
E.A. Wheeler
Professor Emeritus
WPS, Box 8005
Department of Wood & Paper Science
Raleigh, N.C. 27695-8005
USA

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