to Dr. Steven Jansen

From: Patricia Soffiatti <soffiatt@usp.br>
Subject: to Dr. Steven Jansen
Date: Fri, 11 Oct 2002 17:37:09 -0300

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Answering Dr. Steven regarding vascular tracheids in cacti woods. 
 

 
I've been working on cacti wood anatomy since my master degree, together 
 
with Dr. Angyalossy Alfonso, my supervisor. We do not agree with the term 
 
"wide band tracheid". Mauseth and other authors that study cacti wood 
 
anatomy have been using this term, refering to a fusiform non living cell, 
 
with helicoidal thickenings that projects far into the cell lumen (Gibson & 

 
Nobel 1986) - that's why they call it "wide band t.", because in transverse 

 
section, you can see how wide this thickenings can be. According to Gibson's 

 
surveys on Cactaceae wood anatomy, these cells would probably represent a 
 
modified fibre, as they are generally found on "non fibrous woods". What 
 
means: cacti which have a wood that lacks fibres, have these tracheids 
 
instead. I would not say it's a new tracheid type. It's a non perforated 
 
conductive cell, that means: a tracheid. As far as I know, Cactaceae have 
 
simple perforation plates on vessel elements, independently of the presence 

 
of vascular tracheids. We have never seen vestured pits in the species we 
 
have been studying, even under SEM, nor heard about any remarks about in 
 
other cacti species. Anyway we'll keep looking! ; ) 
 

 
Best wishes, 
 
Patricia 
 

 
Patricia Soffiatti 
 
Instituto de Biociências - Universidade de São Paulo 
 
Departamento de Botânica 
 
Rua do Matão 277 - São Paulo - SP - Brazil
 
Fone 11-3091 7542 
 
Fone/fax 11-3091 7547

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