hort.net Seasonal photo, (c) 2006 Christopher P. Lindsey, All Rights Reserved: do not copy
articles | gallery of plants | blog | tech blog | plant profiles | patents | mailing lists | top stories | links | shorturl service | tom clothier's archive0
Gallery of Plants
Tech Blog
Plant Profiles
Mailing Lists
    Search ALL lists
    Search help
    Subscription info
Top Stories
sHORTurl service
Tom Clothier's Archive
 Top Stories
New Trillium species discovered

Disease could hit Britain's trees hard

Ten of the best snowdrop cultivars

Plant protein database helps identify plant gene functions

Dendroclimatologists record history through trees

Potato beetle could be thwarted through gene manipulation

Hawaii expands coffee farm quarantine

Study explains flower petal loss

RSS story archive

Re: still more broken color

  • Subject: Re: still more broken color
  • From: irischapman@aim.com
  • Date: Mon, 05 Jan 2009 23:32:36 -0500

This is something that also comes up relatively often with crossing of
two different but closely related species, but from a different
mechanism. Plastids, including chloroplasts and chromoplasts, have
their own genetic material. Plastids were originally an independent
organism (a photosynthetic cyanobacteria) which formed a symbiotic
relationship with early plant material. The current theory is that this
happened twice independently in plant evolution. Over time these
plastids have lost 90-95% of their genetic material. Most of it ended
up in the cell nucleolus. Thus the plastids have their own genetic
material, but it is under control of the nucleus genetic material.
There are biochemical signals sent from the nucleus which control the
genetics of the plastids. Each species differs some what from other
species in how these signals are sent and interpreted. When different
species are crossed, we can get a mistranslation of signals and the
plastids never get the signal to produce chlorophyll, and thus the
white seedlings, which don't survive unless there is a tiny amount of
chlorophyll. Sometimes these tissues are grafted onto a normal
chlorophyll plant for research purposes.

Usually these seedlings are solid white. In the streaked ones there
likely is a separate mechanism at work. This involves gene silencing.
this is where one gene, often paternal gene is turned off through
methylaion. Thus normally control of the plastids wou
ld be under
control of maternal genes. In inter species crosses this may not work
properly, so both of the plastid control genes (maternal and
paternal)are trying to do the job, and thus mixed messages are sent to
the plastids..

If this is indeed what is happening here there may be dramatic
differences in reciprocal crosses in regards to variegated foliage. Do
you have any information re reciprocal crosses?

Chuck Chapman

still more broken color

Posted by: "Donald Eaves"


Mon Jan 5, 2009 8:18 am (PST)

So, Chuck, is it the same reactivation of inactive genes
that cause the

variegated foliage? A transposon at work? The occurrence of the

streaked with white is even more common in results from TBxAB than

color blooms. In this case of AUTUMN ECHO X KOKO KNOLL both occurred.

Unfortunately these plants aren't sturdy in my growing conditions and

don't survive for too many seasons. Last I looked this one was still

hanging on but has never done well. Too bad since the combo of broken

bloom with the white streaked foliage is a different stroke among the


Donald Eaves


Texas Zone 7b, USA

Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index

 © 1995-2017 Mallorn Computing, Inc.All Rights Reserved.
Our Privacy Statement