Microbial enhancement of seed germination in Rosa corymbifera 'Laxa'

Title: Microbial enhancement of seed germination in Rosa corymbifera ‘Laxa’

Authors: Morpeth D.R.(1); Hall A.M.(2)

Authors affiliations: (1): Writtle College, Writtle, Chelmsford, CM1 3RR, UK (2): Environmental Sciences, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK

Published in: Seed Science Research, volumn 10, pages 489-494, (2000).

Abstract: “Germination of native tree and shrub species from seed can be unpredictable. Germination of Rosa corymbifera ‘Laxa’ was 2% under normal commercial conditions. This was obtained in the presence of the natural microflora found on the seeds. The microflora originated on the hips and the seeds become inoculated during extraction. Exclusion of microbes from such pretreatments resulted in no germination. Inoculation of surface sterilized seeds with members of the natural microflora resulted in 3% germination. The addition of GarottaTM, a commercial compost activator, to the commercial pretreatment increased germination to 95%. This high germination percentage was sustained over a 5 year period using seeds from the same stock bushes. Addition of the compost activator resulted in a 20-fold increase of microbial activity in the pretreatment mixture, indicating that enhanced microbial growth resulted in higher and more predictable germination percentages.”

Link: www.ingentaconnect.com/content/cabi/ssr/2000/00000010/00000004/art00008

Henry, and all,

I read this article and tried this method: treating seed with a commercially available compost activator (‘Concern’ brand, from Necessary Organics, Inc of New Castle, VA) in either 2002 or 2003, using some OP seeds I’d not otherwise have germinated.

Either I did it wrong, or the compost activator was the wrong kind, or something else-----

Anyway, I had one or two germinations from about 350 seeds. The normal germination of those seeds is greater than 20%.

Did anyone else try this method when this article was first in the news?

Peter, can you give the details of how you applied the method?

Henry,

As I recall, I took about 2 tablespoons of the starter (it’s sort of ash-like and gritty) and mixed it with the wet seeds. I left that bunch together for a day or so, and then assumed that the inoculum had done its job, sort of rinsing it off (I wasn’t really careful to get everything off the seeds) and putting the seeds in a baggie to which I added enough damp planting medium (RediEarth peat-lite plug mix) to permit the seeds to germinate. The baggie was left in the refrigerator for a while and on the front porch for a while (for the fluctuating temperatures). I got one germination in the spring (the seedling was defective and did not grow) and another in the late summer. The summer seedling did not grow either. I still have the baggie and the seeds. There has been no further germination. I began this experiment in January 2004, right after you posted this information last year. See link below.

At the time, I went looking for further information on this subject, and found a brief report, since moved to http://www.green-seeds.com/land_flor5.html. The report (summarizing the findings of A.S. Razvi and D.W. Kramer. 1996. Evaluation of compost activators for composting grass clippings. Compost Science and Utilization 4:72-80,) concludes that the compost activators were not very useful for their intended purpose and that in a compost pile, “the most important additive is still work.”

I don’t know whether the compost activators are better at encouraging rose seed germination than they are at hastening the composting of grass clippings. In my case the compost activator did not work as well as the inoculum did in the Morpeth, et. al. research. I’d be very interested to know whether anyone else has tried such an experiment. Maybe we need a special inoculum?

Link: www.rosehybridizers.org/forum/message.php?topid=3109&rc=1&ui=593981801

It may be that you had the same problem that I suggested in the earlier thread. The successful experiment used virmiculite (“The pretreatment consisted of adding the compost activator to the seeds mixed in moist virmiculite then keeping the mixture for 12 weeks at 25 C followed by 12 weeks at 4 C.”)

Virmiculite is inert. Anything organic (like peat) would also be decomposeed by the compost activitator. This decomposition of a large organic mass would generate heat. The heat could either kill the seeds or put them in secondary dormancy.

Another thing - I would suggest NOT using chlorinated water in any experiments involving digestive enzymes or compost activators.

Clearly there was no large organic mass, and I felt no heat in the baggie, but maybe my procedures were incorrect.

Will take some OP seeds and try it again, this time with vermiculite alone as a medium and with distilled water. Tune in later (much later) either here or (more likely) in the Newsletter for a report on this experiment.

Maybe someone else can also try it and we can compare notes. (Are you there, Henry? This means you too.)

Last year I tried a compost activator with seeds in sand (no organic matter) and I used well water with no chlorine. Germination was much lower than normal.

It should be noted that there are many different formulations of compost activator on the market. Depending on the brand, it may or may not contain microorganisms, enzymes, and nutrients. As I recall, the one that I used contained microorganisms without enzymes or nutrients. Perhaps one of the other forumulations would have worked better, but given the poor results of my first experiment, I haven’t been in a hurry to try again.

Jim, could you tell us the brand and the experimental details?

The idea of microbes helping germination in roses and other species as well is very fascinating to me. Some species of fungi produce gibberellins and for GA sensitive species germination is promoted in natural settings where there is leafmold, seeds, and these fungi present. In fact, commercial GA 3 and GA 4+7 are still generated by fungi and are more affordable than other gibberellins because of extraction from fungi. In addition to GA, fungi of course can break down the seed coat to allow water to penetrate more easily.

Years ago I used to clean my seeds well, use captan, and germinate in perlite to try to keep things sterile. The captan kind of stunted seedlings to some degree (especially the roots) which I didn’t like. Eventually I switched over to germinating seed in baggies of peat moss. When I control the moisture (too much rot too little dried out seeds that don’t germinate) I obtain a little bit of white fungi that does not hurt the seeds or seedlings and usually have relatively good germination rates. The past few years I have been using the same bale of peat for my rose seeds. Towards the end of last fall I ran out of it and started a new bale. This new bale had a different texture and in the end with what seemed to be the same moisture resulted in what seemed to be more rotting of seeds and seedlings. I think a very important factor which is hard to control in this whole process is what species of fungi one has present. This can be very difficult to control unless one tries to sterilize their seeds and directly innoculate with a known fungus or group of fungi. Hopefully the compost activator doesn’t aid pathogenic microbes we may have present.

Sincerely,

David

I have spent some time searching the literature to try to find out which fungus would help germination.

In the past several hybridizers (including me) have stated that when they do a sloppy job of cleaning their seeds they often get very good germination. Because of this observation, last year I took some of my rose hip “remains” added water and let the mixture set for about a month in the garage. I then used the water from this “tea” to wet the sand in my petri dishes when the sand needed more water (the seeds are not covered with the sand, they sit on the surface). I did not notice any huge change in germination (I normally use a bromelain / water mixture to wet the sand. A number of years ago I ran controlled tests (with a blank) and found that the bromelain / water mixture did increase the germination rate. (I used to have the graph on my web page, but I now do not have any storage space left so anytime something new is added to the web page something old must be removed.)

So far in searching the literature it appears that Bacillus subtilis may be useful to enhance germination (see page 33 of the “Catalogue of Beneficials” which is downloadable from www.rinconvitova.com - a product called “Activate 1005”. The price is right - $1.30 for 50+gram.

Link: www.rinconvitova.com

Maybe this is a good time to bring up the fish emulsion once again, to possibly enhance the numbers of any good microbes that might be present (taking cues from the Canadian study posted about previously). I remember reading in another study or abstract (probably others remember it as well) that using sterilized peat moss had led experimentally to more damping-off before germination than unsterilized peat did, which seems to fit what’s being said here.

I

All the experiments mentioned so far have not even been close to the original experiment mentioned in Henry’s reference. I would think this could be accomplished without too much trouble except GarottaTM will probably not be available but I’m sure a substitute can be used sucessfully. I will let three of my roses make enough self hips to do this experiment just like was done in Henry’s reference. Here is an experiment which was done in Italy using Garotta and it states that other compost activators were used sucessfully in other experiments in Europe. Scroll down to section 3, page 17.

http://www.apat.gov.it/site/_contentfiles/00137600/137639_atti%205-2003%20Nursery.pdf

Patrick

Thank you Pat for the very interesting reference.

An alternate way to soften the seed coat with readily available hosehold chemicals is to use an enzyme drain cleaner that states on the box that it will dissolve paper (or cellulose). I recommend the kind that come as a solid and does not contain a dye.

Bromelain - a digestive enzyme also appears useful from my studies.

http://home.neo.rr.com/kuska/improvementrosegermination.htm

Link: home.neo.rr.com/kuska/improvementrosegermination.htm