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Thu Jan 12 19:02:20 CET 2006

hardy  Aroids)" <ARISAEMA-L at NIC.SURFNET.NL> Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
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From: Massimo Meregalli <massimo.meregalli at UNITO.IT>
Subject: Re: Emailing: dormancy
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Hi everybody! 
 
the problem of dormancy in tuberous plants has been studied in various
scientific papers. Unfortunately, and perhaps obviously, most of these
papers dealed with potato tubers. Of course, things can be very
different in Araceae. However, dormancy is generally induced, and
interrupted, by the levels of some plants "hormones", such as
gibberellines, auxines, etc. On a pure evolutionary thought, the onset
of a kind of triggering mechanism based on the concentration of a
molecule inside the plant tissue seems to be quite favourable in the
case of the tubers, which cannot be stimulated by daylength, and may
have also a difficulty in being triggered by temperature, if they are
deep enough. Interruption of dormancy can thus be determined by changes
in concentration and or balance of various plant hormones. In case that
these changes are determined by the activity of some enzymes, only
initial concentration and rate of decay or modification can be
responsible for the onset of the new vegetation, rendering thus the
tubers relatively independent from the climate or daylength. The system
may have evolved so that the tubers sleep long enough to pass winter in
cold areas. This could also explain the different times of emercency in
tubers of the same species grown in the same condition. 
 
Best to all! 
 
massimo 
 
<pre class="moz-signature" cols="72">--
Massimo Meregalli
Dept. Animal Biology
University of Torino
V. Accademia Albertina, 13
I-10123 TORINO
ITALY
Tel.: + 39.011.670.4553
Fax: + 39.011.670.4508
Cell: + 39 347 676.94.59
e-mail: <a class="moz-txt-link-abbreviated" href="mailto:massimo.mere=galli at unito.it">massimo.meregalli at unito.it</a>
<a class="moz-txt-link-freetext" href="http://biologia.campusnet.unit=o.it/cgi-bin/docenti.pl/Show?_id=meregalli">http://biologia.campusnet.u=nito.it/cgi-bin/docenti.pl/Show?_id=meregalli</a>
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