Yeah, I don’t believe in hammering seeds but I am told it works even if you don’t believe in it.
FWIW I’m all in favor of undressing embryos but I have enough experience to know that you need to get them fully naked to have any fun with them.
We are fortunate that the following paper appears to be available free for personal use:
It carries the following restriction:
“This article appeared in a journal published by Elsevier. The attached
copy is furnished to the author for internal non-commercial research
and education use, including for instruction at the authors institution
and sharing with colleagues.
Other uses, including reproduction and distribution, or selling or
licensing copies, or posting to personal, institutional or third party
websites are prohibited.”
Google Scholar does provide a link to it. I am not posting the article but only the Google Scholar link to it.
This full paper is also available:
Thanks Dr. Kuska.
These guys are ambiguous on their protocol, referencing this paper instead:
Svejda FJ (1968). Effect of temperature and seed coat treatment on
the germination of rose seeds. HortScience 3: 184–185.
It is important to know the protocol because they claim improvements in germination rates and totals with scarification whilst not revealing the basis for comparison - that is to say, improvement over what? They seem to be following a strategy of holding the seeds in a warm after-ripening period which I contend allows time for infection and expiration of some of the embryos. Moreover, they aren’t imbibing with ice water which I contend benefits germination by increasing oxygenation and, at the very least, doesn’t suffocate the embryos like, say, soaking in room temperature water in a hot environment like, say, Pakistan has.
One thing that’s clear is that their sample is a very narrow one, basically a small set of thermophiles that should, anyway, germinate with a minimum of stratification. The pericarp thicknesses, in particular, are much less than breeders along the northern tier will be experiencing with acclimatized breeding stock.
I could go on but it would be nice to read Svejda’s 1968 paper first if somebody can dredge it up.
Don,
Svejda wrote a follow-up paper in the RHA Newsletter in 1972 with some details of his experiments.
http://bulbnrose.x10.mx/Roses/breeding/SvejdaGermination1972.html
Rowley (1956) also found that a period of warm after-ripening was helpful.
http://bulbnrose.x10.mx/Roses/breeding/Rowley/caninaseeds/caninaseeds.html
Crocker (1927) only discussed cold stratification.
http://bulbnrose.x10.mx/Roses/breeding/Crocker/Crocker_seeds.html
Several of Svejda’s papers are listed (some with links to PDFs) here:
http://www2.ville.montreal.qc.ca/jardin/archives/svejda/svejda_pub_en.php
To all of you who posted techniques and links to articles, thank you VERY much. This coming fall I will try several of the methods you described. Will measure the germination rates where the cross is a constant but the CaNitrate and stratification media are variables.
I will definitely try CaNitrate as an overnight soak and in several different stratification media. I had never tried vermiculite before but will try it this fall.
For my most precious crosses, I will cut a hole into the outer seam to help get the calcium nitrate in and help the embryo to push a root through.
My seed numbers are not that great, around 200 seeds this year, but I will try to make my sample sizes large enough to get a decent reading of the results.
Again, thank you all.
Cathy
Central NJ zone 7a
Cathy, if you go to the home page for RHA and look under resources, I believe you can find my review of germination techniques. I think you’ll find it includes every credible paper on the subject up through about 2010. I searched every database I could find and tracked down every article cited by each of those articles that I could acquire. I read Crocker’s book end to end (actually a couple decades ago when I found it in the library stacks, then again for this review.) While I couldn’t describe all the techniques in detail for want of space, I did tell what was tried and whether it did any good. So you can save yourself a lot of trial and error by beginning there.
Nadeem’s work is not impressive, or reliable. Anyone who cites Tincker and Wisley has obviously not read the paper. Tincker had an M.A. and worked at Wisley. Wisley is a botanical garden located in England. The first erroneous citation that I can find for this is an article out of Alaska on germination of native plants, including roses. Tracing mis-citation is a great way of finding out who has actually read the literature, and who’s faking it. The most common error I’ve seen is mis-spelling the second name in Lineweaver and Burk(e), adding the e for attribution for a once-famous chemist who worked for the USDA. This error seems to be most common in India. Only a small fraction of those citing the Lineweaver-Burk method have ever read the original. If they had, they would know what was the actual topic of the article. With many reputable journals appearing on-line for free, and the availability of complete data-bases in most of the university libraries around the world, there’s no excuse for university students any more. And Google makes it possible for most of the rest of us to find most of what we need too.
I believe we had an earlier thread on issues of plagiarism out of Pakistan. Check that one out by doing a search here. Sulfuric acid does not have a good reputation as an effective tool for enhancing rose achene germination. It works well on hard-seeded legumes such as Kentucky coffee bean, or black locust or even wild soybean (but not the usual cultivated kind). I believe Denison Morey compared a lot of chemical treatments. So did Henry Kuska. I’m too lazy to look up all the refs right now, but they are in the review. David Z. was kind enough to share with me a review by Frank Buckley that included a lot of things tried in the U.K. and not published widely. If you or anyone else finds some article I’ve missed, please let me know and I’ll add it in a revision during the next year or so. Once every five years is about often enough for me.
Your testing plan sounds fine, but realize you’ll need a fair number of seeds for each treatment to get good statistics. Generally speaking 20-25 allows reasonable confidence if the difference is 25 % or more. You need >100 if you want to believe 10% differences. That’s why I used samples at least that big for most of my tests that are written up in the RHA newsletter. Of course for special crosses there’s no way to get even 100 seeds in one season, so it’s hard to know how many treatments to do for comparison.
Larry, I found the article: A Century of Rose Germination Techniques, and will read it over the weekend.
Thank you very much!
I bought 8 new rose breeding mothers to test this summer. Adding those to my existing mothers, hopefully, I can get some sample sizes that come close to the ones you suggest. I will publish my results next spring.
Again, my great thanks to all of you who shared your experience in this thread.
Regards,
Cathy
Central NJ zone 7a
So far the use of red light has not been emphasized. When I had RoadRunner web pages, I had this article posted. This is copy of it without working links:
Improvement Of Rose Seed Germination With Red Light
Earlier version published in The Rose Hybridizers Association Newsletter, Volumn 28, No. 2, Summer 1997, pages 3-4.
In 1980 Paul Jerabek wrote the following to me: “Exposure to red light seemed beneficial in one experiment but subsequent treatments cast doubt on those results.”
In the early 1990s I was germinating my rose seeds in a sun room that had windows on the north, west, and east side. I noticed that I had the earliest germination in containers that were placed on the north side near to the west side. In this position the seeds, which were sitting on a wet surface and enclosed in clear containers, received direct sunlight only in the evening (the red light of the setting sun).
In 1995 Y. Yambe, K. Takeno, and T. Saito published a paper titled: “Light and Phytochrome Involvement in Rosa multiflora Seed Germination”: in J. Amer. Soc. Hort. Sci. 120,953-955(1995).
The abstract is: " Seed germination percentage of multiflora rose (Rosa multiflora Thunb.) was much higher under continuous white light than in complete darkness. Red light was the most effective in inducing germination, and far-red light was ineffective. Exposure to red light for 1 min increased germination; this effect was saturated at an exposure of 2 min. The red-light effect was reversed by subsequent exposure to far-red light. The results indicate that rose seeds are positively photoblastic, and that the photoreceptor involved is most likely phytochrome."
The actual article includes a very important experimental detail that was not included in the abstract. This experimental detail is that the experiments were done on seeds that were first treated with enzymes to soften (partially dissolve) the seed coat. I would expect that this treatment would facilitate the light penetration into the seed.
Their “Results and Discussion” section starts with the following: “Germination percentage was >60% under light, whereas germination in darkness was negligible”. Later in the discussion section they state that “Almost no germination was observed in darkness in the early experiment (Fig.2), whereas about 10% or more seeds germinated in darkness in the later experiments … This fact suggests that R. multiflora seeds are strictly photoblastic immediately after harvest, but this may change as the achenes age …”.
In their Figure 2 they showed that when seeds were treated with Driselase for 36 hours and then placed under continuous white light that the germination percentages rapidly rose to about 60% in about 6 days and only a few more by day 15.
Although the main study was on rosa multiflora seeds, the authors did make the following statement: “Preliminary experiments with seeds of R hybrida ‘Inspiration’ resulted in a similar conclusion (data not presented)”.
Another paper reports germination data on rosa multibracteatae seeds that support the photoblastic model. In their Figure 2 untreated seeds germinated in darkness had about 30 % germination after 24 weeks while untreated seeds stratified under alternating 14 daylight / 10 hours darkness gave about 37 %. Please note that these data are for seeds that did not have an enzyme treatment. The difference in germination did not become apparent until after the 16 th week of stratification. This would be consistent with a model that the seed coat had to be softened/thinned before the light effect could take place.
Experiments on the germination of embryos removed from immature seeds (embryo rescue) are consistent with the photoblastic model as the final stage of embryo development is done either in continuous light or in alternate light/dark periods, see for example the paper by Mohapatra and Rout.
An explanation for the red light enhancement of seed germination is: nature has provided the seeds with a mechanism by which they can detect whether they are close enough to the soil surface to survive if they would germinate (see for example, page 192, Plant Propagation, Sixth Edition, by H. T. Hartmann, D.E Kester, F.T. Davis, and R. L. Geneve, Prentice Hall publisher, 1997). Of the various components of sun light, it is the red part of the spectrum that is able to penetrate a short distance into the soil.
I initially used fluorescent bulbs and covered my seed trays with red transparent paper (following the procedure outlined by Yambe et.al.). Probably the easiest type to find and use is the red colored form of transparent cling food wrap such as the Handi-Wrap Brand Plastic Film or clear red wrapping paper found in party stores.
I now use red LEDs as the light source. Ebay has been a good source for LEDs.
Phytochromes allow plants to distinguish red vs. infrared light. Infrared = heat.
During hot weather, the soil remains warm (i.e., radiates infrared) for some time after sunset. Phytochromes that were “saturated” by red light from the setting sun will soon become saturated by infrared light radiating from the warm soil.
The ability to deterimine whether the last light of day is red or infrared allows seeds to germinate in Spring, when the last light of day is red (the soil being cool), while avoiding Summer (last light being infrared).
So, when discussing phytochrome-related phenomena, we must keep track of soil temperature as well as the color of the visible light.
[quote=“Henry Kuska”]So far the use of red light has not been emphasized. When I had RoadRunner web pages, I had this article posted. This is copy of it without working links:
Improvement Of Rose Seed Germination With Red Light
Henry, I currently germinate my rose seeds in a barn that has a perfect temperature range of 45 to 50 degrees F.
But they are in almost darkness, with indirect light coming from windows that are 10 feet or more from the seed flats.
The barn has regular ceiling lights.
Which do you think might be better, keeping the ceiling lights on… the bulbs can easily be replaced… or installing a “floor lamp” that has red bulbs in it?
I am totally open to trying either approach.
Cathy
Central NJ, zone 7a
I would recommend red LEDs from strings of all red LED Christmas lights. They would not be heating up the trays very much, and they would not be using much power.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CDQQFjAD&url=https%3A%2F%2Fwww.nabt.org%2Fwebsites%2Finstitution%2FFile%2Fpdfs%2Famerican_biology_teacher%2F2009%2FAugust%2FABTAug09Neff367-70.pdf&ei=TD3WVLaBNIqegwTf24LACQ&usg=AFQjCNEvJtYUK4-jMncNiM3eiGIVq5nmAw&sig2=T1uVUZWlwounDw76y5UmDA&bvm=bv.85464276,d.eXY&cad=rjt
This is for germination only. For growth, I recommend balanced 24 hour lighting.
Henry,
I am puzzled. If red plastic wrap has any beneficial effect (as opposed to clear wrap of the same type) then it is unlikely that phytochromes are involved. The same goes for red-coated incandescent bulbs vs. clear bulbs of the same type. The fact that red plastic wrap looks red informs us that it is reflecting red light. Thus, seedlings growing under red plastic wrap receive less red light than those under clear wrap.
Is there evidence that visible light of other colors can inhibit germination of rose seeds?
A quick search did turn up some info on germination of Nepenthes seeds under different colors of light. Seeds germinated more quickly under red light, but those under white or yellow light were more vigorous with more leaves and roots.
International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies (2011)
Effects of Different Light Treatments on the Germination of Nepenthes mirabilis
Anchalee Jalaa* a Department of Biotechnology, Faculty of Science and Technology, Thammasat University, THAILANDSeeds of > Nepenthes mirabilis > were germinated > in vitro > on composted medium. All seeds were germinated under white (fluorescent), red, green, blue and yellow light. Over a period of 27 days, some Nepenthes seeds under white and red light germinated first, and those under green light were the last ones to germinate. The highest average speed of emergence was recorded for seedlings under red light. All healthy and complete seedlings were counted after 60 days. Seedlings under yellow light were the most vigorous with the highest germination index and average height of 0.79 cm. Seedlings under yellow light and white light exhibited the highest average number of roots and light green leaves as well as greatest root length, but seedlings under green light had few roots and pale green leaves. There were more young leaves on seedlings under yellow light (average 5.2) and red light (average 5.0) compared with those under green light and blue light.
Karl after germination balanced light is used for growth. The red light is only for germination.
Karl you are defining reflected light, this use is filtered light.
Henry,
Not at all.
Any red light that is reflected by the plastic wrap, is not being transmitted through it. Hence, the red light passing through the filter is only a fraction of the red light that is produced by the light source.
Red LEDs are a different matter, of course.
"If you pass white light through a red filter, then red light comes out the other side. This is because the red filter only allows red light through. The other colours (wavelengths) of the spectrum are absorbed. Similarly, a green filter only allows green light through. This is called colour by subtraction.
So when, for example, a red filter is placed in front of the spectrum above only the red part of the spectrum remains - the rest disappears.
N.B. The whole spectrum in NOT dyed red - the red part of the spectrum remains but the rest of the spectrum has been absorbed by the filter."
https://www.le.ac.uk/se/centres/sci/selfstudy/lht5.htm
The use of filters and transmission vs reflection is a really tricky one. We spend a long time on it in our lab classes trying to explain about subtractive effects. But the more important thing is that there are different qualities of light, and our eyes only perceive a portion of the whole spectrum. Our eye doesn’t detect well in the far red or the uV regions. So sometimes a filter will appear red, but could be transmitting both far-red and red, or red and uV (if made of the right glass or plastic). For some filters that you can buy, a description is available for exactly what range of light it transmits. For others, no such luck. Gelatin filters used in theaters, or cellophane filters, are not particularly clean in the range of light wavelengths they transmit. They are based on mixing a colored dye into a plastic medium. All we care about is how they look to our eye. The plant may see it differently. The red filters do seem to work in some experimental systems and have been used in schools ever since the discovery of the light effect on germination back in the 1940s.
Red LEDs are much cleaner, if they are really red emitting and not just white with a red plastic coating. Look at one when it is turned off. It ought to be colorless if it is really a red LED. You can also buy far-red LEDs which are usually called infrared. They are used in lots of sensor-based machines. A place like Radio Shack if still in business may have some cheap ones to play with.
If you use cellophane type red transparent paper with florescent light, the fact that the red filter may transmit some infrared is not of practical importance since:
“Fluorescent light bulbs are designed to save energy and reduce heat by only emitting visible light. There is still just a bit of near IR that is emitted but this is so low of an intensity that infrared photography under fluorescent lighting is impractical.”
If the illuminated side of the filter appears red, it is because part of the red light from the source is being reflected rather than transmitted. Also, some of the red light is absorbed by the filter. Only the transmitted portion of the red light can affect the seeds. Removing the filter would allow more red light to reach the soil and seeds, while also allowing other wavelengths to exercise their own influences.
I am not trying to be argumentative. I am trying to get at what - exactly - is supposed to be at work. If phytochrome is involved, it should be a matter of red vs. infrared. But otherwise it may be that some other color (yellow, green, blue) is inhibiting germination.
Garner and Allard (1920) wrote: “The comparative effects produced by different regions of the spectrum, including the ultra-violet, have been extensively investigated but with more or less conflicting results. The most extensive investigations on the subject, perhaps, have been made by Flammarion (8). It was found that there is abnormal elongation of the principal axis in several species under the influence of the red rays, while growth is markedly reduced under the green and especially under the blue rays.”
So, do seeds sown under red light germinate a little more quickly because of this “elongation of the principal axis”?
The link is to a 2014 published, reviewed scientific article. It will give one an idea as to where this field is now.