POC observations so far

[Toby Kellogg]

Just a simultaneous addition to Felipe's comment:
Unisexual flowers are pretty common in Poaceae and in angiosperms in
general.  Among model systems they occur in Populus, sugar beet, Silene,
and the outer florets of some sunflower relatives, so if we can solve the
problem for maize, we will have solved a number of similar problems.  The
difficulty is that in maize, as in many angiosperms, all flowers start
development as bisexual structures; in staminate florets, the pistil then
aborts.  This means that the structure:
>----%tassel
>-------<staminate floret; synonym: male floret
>----------<androecium
>-------------<stamen
>----------------<anther
>----------------<stamen filament
also should include gynoecium, pistil (and nucellus, ultimately), and
ovary, but not style and stigma.   As long as style and stigma are
daughters of pistil, there's a problem.  The gene tasselseed2 is expressed
in the young ovary of the staminate florets in the tassel, and we can't
describe its expression pattern accurately unless staminate flowers are
allowed to have pistils somehow.  Pankaj's idea of including "rudimentary
gynoecium" certainly seems like a step in the right direction, as long as a
search on gynoecium will find the rudimentary ones as well.
toby

>Lincoln Stein wrote:
>
>> The stigma issue is harder and I suspect it represents an incorrect
>>structure
>> in the tassel->floret->gynoecium->pistil path.
>>
>
>The problem with maize is often the male and female florets occur in the
>female
>and male inflorescences respectively. Though this is not a normal
>condition. I
>agree with Sue, when we have the implementation of slots/properties linking
>different anatomical terms at some point in future, we should be able to
>build
>the correct structures. Please let me know if the following structure works.
>
>inflorescence
>----%tassel
>-------<staminate floret; synonym: male floret
>----------<androecium
>-------------<stamen
>----------------<anther
>----------------<stamen filament
>----%spike
>------%spike  (sensu zea); synonym:cob
>-------<pistillate floret; synonym: female floret
>----------<gynoecium
>-------------<pistil
>---------------<style
>---------------<stigma
>---------------<ovary
>----%panicle
>--------<perfect floret
>----------<gynoecium
>------------<pistil
>--------------<style
>--------------<stigma
>--------------<ovary
>----------<androecium
>------------<stamen
>--------------<anther
>--------------<stamen filament
>----%capitulum (sensu compositae)
>--------<ray floret
>--------<disc floret
>----<floret
>------%floret
>--------%ray floret
>--------%disc floret
>------%floret (sensu Poaceae)
>--------%perfect floret
>----------<gynoecium
>------------<pistil
>--------------<style
>--------------<stigma
>--------------<ovary
>----------<androecium
>------------<stamen
>--------------<anther
>--------------<stamen filament
>--------%imperfect floret
>----------%staminate floret; synonym: male floret
>-------------<androecium
>---------------<stamen
>---------------<anther
>----------%pistillate floret; synonym: female floret
>-------------<gynoecium
>----------------<pistil
>------------------<style
>------------------<stigma
>------------------<ovary
>
>
>
>
>> Lincoln
>>
>> On Thursday 02 October 2003 02:45 pm, Toby Kellogg wrote:
>>
>>>Hi all -
>>>  Felipe has made great progress here downloading the various programs
>>>necessary for viewing and manipulating the ontologies.  He's run into some
>>>mechanical problems that he can sort out with Pankaj, the most critical
>>>being trying to get two DagEdit windows open at the same time so two
>>>ontologies can be viewed side by side.  In terms of the ontologies
>>>themselves, we immediately found a number of terms that are not in common
>>>use, or are in odd hierarchical relationships; these should be easy enough
>>>to change.
>>>  A more interesting and complex issue comes with species-specific terms.
>>>An easy one is "silique" in Arabidopsis, which would be an instance of
>>>"fruit" if one is working with multiple species.  A more difficult one is
>>>"stigma", which is a part of "pistil", part of "gynoecium", part of
>>>"floret", etc. up to tassel.  Unfortunately, stigmas do not form in
>>>tassels, because the gynoecium stops developing.  Similarly, "abscission
>>>zone" is part of "silique" in Arabidopsis, and would end up being part of
>>>"fruit" if "silique" were interpreted as an instance of "fruit".  However,
>>>abscission zones do not form in the grass fruit so couldn't be a part of
>>>fruit.  in both cases we end up violating the True Path Rule.  It may be
>>>that this is inevitable, since the descriptors aren't strictly
>>>hierarchical.   Obviously one can get around this somewhat by creating
>>>species-specific bits of the hierarchy, and by making creative use of
>>>"sensu"; this will probably work fine as long as the ontology only has to
>>>apply to Brassicaceae and Gramineae.  If the long-term goal is to make it
>>>apply to all flowering plants, though, there may be a limit to how
>>>species-specific we make the ontologies.   For example we could divide
>>>fruits into indehiscent and dehiscent and then have abscission zone as part
>>>of dehiscent fruits, which would be OK until we get to a fruit that forms
>>>an abscission zone but doesn't dehisce.  Another possibility that Felipe
>>>and I explored a little would be to add another category of connection,
>>>such as "a process that can occur in"  - in addition to "is part of", "is
>>>an instance of" and "develops from".  I suspect that another category might
>>>create more problems than it solves, but it seemed worth considering.
>>>  Any thoughts on this are welcome!
>>>Toby
>>>
>>>Elizabeth A. Kellogg
>>>Department of Biology
>>>University of Missouri-St. Louis
>>>8001 Natural Bridge Road
>>>St. Louis, MO 63121
>>>phone: 314-516-6217
>>>fax: 314-516-6233
>>>http://www.umsl.edu/divisions/artscience/biology/Kellogg/Kellogg/
>>
>>
>
>--
>******************************************
>Pankaj Jaiswal, Ph.D.
>Research Associate
>Dept. of Plant Breeding
>Cornell University
>Ithaca, NY-14853, USA
>
>Tel:+1-607-255-3103 / Fax:+1-607-255-6683
>E mail: pj37 at cornell.edu
>http://www.gramene.org
>******************************************


Elizabeth A. Kellogg
Department of Biology
University of Missouri-St. Louis
8001 Natural Bridge Road
St. Louis, MO 63121
phone: 314-516-6217
fax: 314-516-6233
http://www.umsl.edu/divisions/artscience/biology/Kellogg/Kellogg/