Heterospory

Janice M. Glime jmglime at MTU.EDU
Tue Oct 21 14:55:36 EST 1997


I forwarded this question to bryonet-l at mtu.edu.  Here are the responses so
far:

Date: Mon, 20 Oct 1997 07:31:53 +1000
To: bryonet-l at mtu.edu
Subject: Re: Heterospory (fwd)
Reply-To: bryonet-l at mtu.edu

I suggest also that people have a look at:
Mogensen, G.S.  1981.  The biological significance of morphological
characters in bryophytes:  The spore.  The Bryologist 84(2):  187-207.

Rod Seppelt

Dr. Rodney D. Seppelt
Principal Research Scientist
Australian Antarctic Division
Channel Highway
Kingston 7050, Tasmania, Australia

phone:  International:  +61 (03) 62 323 438
        FAX          :  +61 (03) 62 323 351
        Alternate FAX:  +61 (03) 62 323 449

***********************************************************

Date: Sun, 19 Oct 1997 10:54:19 -0500
To: bryonet-l at mtu.edu
From: Bernard Goffinet <goffinet at duke.edu>
Subject: Re: Heterospory (fwd)
Reply-To: bryonet-l at mtu.edu

Heterospory refers to spores often different sizes that are produced in two
distinct sporangia: the large spores typically or always give rise to the
female gametangia; these spores would be produced in the megasporangium;
the smaller spores, the male one are produce in the microsporamgium.
Selaginella is usually used to show this pattern.  In mosses, a single
sporangium is present, and spores of different sizes or "of different sex"
are all produce in a single sporangium.  The difference is that in
Selaginella, spores produced by meiosis are all the same within a single
sporangium; whereas in mosses with male and female spores, or small and
large spores, a spore mother cell gives rise to two of each kind.  Dale
Vitt (1968, Michigan Botanist I believe is the title of the journal) wrote
a paper regarding heterospory and anispory.  Heterospory is used to refer
to cases like Selaginella, and is thus never applicable to mosses.  The
term anispory is used in mosses only when the spore size distribution is
clearly bimodal.  Anispory can of course only apply to mosses that are
dioicous, that is with gametangia that are either male or female.  In
anisporous mosses, small spores seem to always give rise to dwarf male
plants (the reverse however is not always true apparently) that grow as
epiphyte on the female plant; such condition is called phyllodioicy or
pseudoautoicy.

I hope this helps.  Bernard

Bernard Goffinet
Department of Botany
P.O. 90339
Duke University
DURHAM, NC
27708 USA
e-mail: goffinet at duke.edu
phone: 919 660 7370
fax: 919 660 7293

***********************************************************
Janice

***********************************
 Janice M. Glime, Professor  
 Department of Biological Sciences
 Michigan Technological University
 Houghton, MI 49931-1295
 jmglime at mtu.edu
 906-487-2546
 FAX 906-487-3167 
***********************************




More information about the Plant-ed mailing list