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Stigma

stigma

The pollen-receptive surface of a carpel or group of fused carpels, usually sticky. The apical end of the style where deposited pollen enters the pistil.An external tracheal aperture in a terrestrial arthropod.A skin lesion that is a diagnostic sign of some disease.The area of a plant where pollen is deposited for fertilisation. Usually the stigma will bear a sweet solution which can attract bees. In turn, the bees will land on the plant, pick up the pollen grains and transport them elsewhere, i.e. to another plant,.


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The Colin Leslie Dean species paradox

... "pollination syndrome" plants have chemical signaling pathways that prevent intra-generic pollination (ie rose pollen lands on iris stigma - nothing happens). On a side note: In my part of the world, the wild irises hybridize so commonly it can be infuriating (impossible) to try ...

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by AstusAleator
Wed Jul 01, 2009 5:21 am
 
Forum: Evolution
Topic: The Colin Leslie Dean species paradox
Replies: 120
Views: 2138

The need to stretch?

... throughout the day, I also stretch. I spent twenty years leading other people to do this stuff. Unfortunately, I feel that there is an unspoken stigma against public stretching. One of my students from years ago put it nicely and bluntly. She said something like, "People who are not in ...

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by robertkernodle
Thu Jun 28, 2007 7:07 pm
 
Forum: General Discussion
Topic: The need to stretch?
Replies: 21
Views: 4194

Late-acting system

... employ late-acting systems,in which the ovule aborts when fertilized or shortly after fertilized when the same flower's pollens fall on its stigma. But the abortion will make this flower lose one chance to spread its genes, though this chance will produce a inferior seed. Is that worth it? ...

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by wtwt5237
Mon Jun 18, 2007 12:54 pm
 
Forum: Botany Discussion
Topic: Late-acting system
Replies: 0
Views: 672

which can survive better;POLLEN OR SPORES?

... think that spores of Adiantum have greater chances of surviving, because they only need a good place for sprouting, while the pollen grain needs a stigma of its spesies' flower. It may have lower chances of coming across one. That's what I think.

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by SU_reptile
Wed May 09, 2007 7:20 pm
 
Forum: Botany Discussion
Topic: which can survive better;POLLEN OR SPORES?
Replies: 6
Views: 1073

A Monkey's Uncle

... complexity to justify your own idea with its premise of non-development from simple to complex? Why create unique carriers? Pollen either finds a stigma or it doesn’t and is wasted. If it finds a stigma then it has to be compatible or is wasted. It’s all the luck of the draw. A carrier such as ...

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by narrowstaircase
Sun Mar 18, 2007 11:46 pm
 
Forum: Evolution
Topic: A Monkey's Uncle
Replies: 26
Views: 5283
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