RE:Hyb: Cytoplasmic inheritence was disease resistance
Usually it is from the same pollen but it can be from two different parents. I was quite interested in this when I read it. It is the endosperm that is fertilized but it seems it that cytoplasm can show effects.
The example I gave re variagated foliage in iris is a compilition of how the genetics works with a form of variagated foliage in corn combined with information about variagated foliage in iris. I have the textbook here in front of me. I went searching for answers when Sandy Ives had three variagated plants show up from two green parents and I went looking for information to explain it. The variagated, (actually atriped like zebra pallida) corn has this type of inheritence where usually there is only stripped seedlings from female plant. The female plant has to have nuclear gene for stripped foliage plus the cytoplasm genetic information. A green female with the gene in the nucleous can produce stripped foliage seedlings if pollen is from a male with the stripped gene in its nucleous.
There is another interesting type of variagated foliage example for the variagated foliage Four O'Clock plant which is strictly throught the cytoplasm of the female plant. No nuclear genetic information in this case strictly cytoplasm.
The whole chapter is on "Extranulear Inheritence" I can't honestly say I follow everthing in the chapter but this is a summery of the corn example which seems to be the same as in iris.Wwhen I went looking I found several other examples of green parents producing variagated offspring in iris. I have crossed several "green from variagated mother" siblings. I'm awaiting results.
Every time I find an answer I find more questions.
Date: Mon, 31 Jan 2005 00:38:13 -0500
From: "Neil A Mogensen" <firstname.lastname@example.org>
Subject: [iris] RE:Hyb: Cytoplasmic inheritence was disease resistance
Chuck, are you sure about what you said about fertilization of the cytoplasm
being from one pollen cell, the nucleus from another? That isn't the
understanding I had.
I think perhaps you are thinking of endosperm, rather than cytoplasm. The
process of fertilization in plants is considerably more complex than in
animals, but the difference lies in the zygote/endosperm difference. One
pollen grain contributes three gametes--one of which fertilizes the female
gamete which becomes the future embryo, the other two the endosperm, which is
triploid as a result, relative to the embryo.
As the seed matures, the endosperm constitutes almost all of the seed, while
the future plant is attached to it by a rather slender filamentous structure
through which nutrients flow to the future plant.
Am I in error?
Neil Mogensen z 7 western NC mountains
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