Link: story.news.yahoo.com/news?tmpl=story&u=/ap/20021125/ap_wo_en_po/na_fea_sci_us_biotech_roses_1
Thanks Jim for the link to this interesting article. I’m really curious about what type of gene was discovered in bacteria for blue pigmentation .
The discussion on rose fragrance was interesting too. A couple months ago I had the pleasure of listening to a seminar by Dr. David Weiss on his fragrance reseach when he was visting Minnesota. The yellow rose was ‘Golden Gate’. In the newspaper article it quotes Dr. Weiss as saying, “Unfortunately, we don’t have the technology to transform the rose,”. Perhaps the reporter misquoted or misunderstood him. Dr. Weiss and his associates found that the fragrance pathways are very complex and for a transgenic approach to be successful, one would need to know what is the limiting step(s) for each cultivar. After that is determined, gene(s) may be able to be pinpointed that could be used for transformation to increase fragrance. The technology exists to transform roses, but the question here is to transform roses with what to increase fragrance? It seems that transgenic roses with increased fragrance and other plant species able to have a “rose” scent through transformation is a ways off.
Sincerely,
David
Dear Jim,
I can’t seem to make that article come up, but I keep wondering if we are going about this the wrong way. In nature, most blue is structural and produced by diffraction, the sky, blue eyes, some of the blue flowers are due to structure breaking up the light waves. I used to raise green parrots and once read a very lucid chapter in a book (about Lovebirds) by George A. Smith of Great Britain. He explained that since blue and yellow color were reflected back to the eye from a “green” feather that a mutation which lost the yellow color would produce blue. The reason for this was that the upper layer of the “green” feather had no color itself (and was called the “cloudy layer” but relected the light back out in the typical fractured pattern which gives blue eyes and blue skies. (He described it better than I do, of course.)
This kind of thing makes me think that those searching for a blue rose would do better to start with Greensleeves, or St. Patrick or Limelight, since these roses have some “green” petals to begin with. Maybe irradiation with a black light at the correct time could produce the right mutation.
I know that there are bluish pigments (my Sapphire Gladioli leak blue-purple dye all over everything in the Spring), but I still wonder about the “structural” aspect.
I continue to try to find articles on the web under “rose petal cross section” but come up with nothing. Does anyone know if rose petals have been examined microscopically?
Has anyone tried to get blue starting from yellow-green??
Thanks, Linda
My understanding is that greenish roses get their color from a green pigment, chlorophyll, rather than a combination of blue and yellow pigments.
BTW, Ralph Moore has some green-flowered seedlings under evaluation. I haven’t heard whether he will introduce them.
Yahoo only keeps news stories online for a limited amount of time, and that story is no longer on their site. Here is another site that has it.
Hi Jim,
yes, I can’t think of an instance when a flower of any kind doesn’t owe it’s green color to the presence of chlorophyll. This explains why green roses last so long and attract more aphids, as the flower actually photosynthesizes with the rest of the plant and why it’s not likely that one could selectively eliminate the yellow pigment from only the flower.
From what I’ve gathered the real problem seems to be that the ph level in roses doesn’t allow the blue pigment to express itself in roses the way it does in the petunia that was chosen as the source for the blue gene.
I think the problem will eventually be solved. There are many other gene sources for blue pigment. Petunia happens to be very easy to tissue culture which is probably the reason it was chosen. I prefer the blue of Delphinium or Lobelia to the blue of petunia.