The page link below gives a introduction to germinating pollen on onion epidermis.
See also:
Also there is a paper which reports the germination promoting behavior of onion, see:
http://pcp.oxfordjournals.org/cgi/content/abstract/9/2/237
Link: www.microscopy-uk.org.uk/mag/ctpollen/Spring_flowers_and_pollen_germination.html
I have not tried this but it is interesting reading. So if I read it right the main practical appplication of doing this would be to see how fertile a male parent was?? Could their be other applications also besides curiosity?
I was thinking about lilies and how some species pollen tube does not extent all the way to the egg so breeders will cut the style to compasate? Could this also point out the male parents that won’t pollinate without help like this?
I was also thinking that maybe this could be used to point out that a female parent may have an inhibator if pollen germinates on the onion but when used on the female fails?
Does these thoughts make sense? And what are your thoughts on the practical applications?
Regarding the possible germinating promoting ability of onion:
I am planning on adding onion oil to an easy to pollinate rose like Carefree Beauty. If it works there (doesn’t kill the pollination), then I will try adding it to a difficult to pollinate bud to see if it helps seed set.
I wonder if garlic oil could be substituted?
It would be nice if the oil would overcome any female inhibiter chemicals. Since rugosas are self sterile, they could be used for such a test.
I had not thought about pollen tube length, but of course that would be useful to know.
I don’t know if roses have different pollen tube lengths. I have not read that anywhere with reguard to roses. But with as many species their are in the rose family I would think there would be some variance.
I would think their would be hardly any difference between onion and garlic oil. One possiable benifit to garlic is that it contain higher concentration of natural antibiotic compounds than onions.
very likely the onion is simply a source of moist sugary environment with some boron and other ions. The pectins in the space between cells (that ghet exposed when the epidermis is peeled) may help retain water, bind calcium and in general act somewhat like a stigmatic surface. Rose pollen is rather easy to germinate according to most sources.
The notion of antibiotic effect and alteration of pollen tube length are both intriguing possibilities to explore.
I was able to find this abstract, but I do not have access to the complete paper:
Title: Germination of chrysanthemum pollen. III. Substance promoting germination.
Authors: Matsubara, Sachiko; Tsukamoto, Yotaro.
Authors affiliation: Kyoto Univ., Kyoto, Japan.
Published in: Plant and Cell Physiology (1968), 9(3), pages 565-72.
Abstract: “Five chromatographic fractions of onion-bulb exts. were assayed for activity in promoting pollen germination in Chrysanthemum moriforlium and C. leucanthemum. Four of the fractions were active, the most potent one of which was composed mainly of neutral substances. The active substances were probably org. since they were more sol. in EtOAc or ether than in water.”
That abstract definately went over my head and only in a few sentances.
The link below shows (Folksinger X William Baffin) pollen that has been on an onion slice for 24 hours.
http://picasaweb.google.com/HAKuska/MicroscopePictures02/photo#5231972786649933474
Link: picasaweb.google.com/HAKuska/MicroscopePictures02/photo#5231972786649933474
I got to the library yesterday and read that paper. It has a back to back set of papers. I had really forgotten how people used to try to do fractionation and identification of stuffs from plants. Very laborious and they still have little clue what it is. It is likely not a simple salt, nor is it an ordinary amino acid, and they claim it is different from the common known plant hormones of that day. But putting their information together with the recent post by Henry on sildenafil, and what I’ve heard from University of Arizona about reactive oxidizing species, including NO and peroxide, it might be one of the thiol compounds (like allicin) found in onions.They would bind NO and perhaps affect the pollen tube growth process.
On the other hand the epidermal promoting effect may not be specific to onion, but might work with any epidermis you could peel off, including something like daffodil, scilla, amaryllis or even leaf epidermis. This kind of comparative study would make a really great science fair project for some enthusiastic high school student. If done decently they might well win national prizes, based on my prior experience with helping students with such competitions.
If it really is specific for onion family we’d have to go at it with modern fractionation methods.
Very interesting, Dr. Kuska. Your spam filter wouldn’t let me use the V word.
I tried 3 times using fresh onion juice only. I used slides that have a concave section designed to hold liquids. Very few pollen germinated in 3 days.