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tripsis

Sulphuric acid treatment for Rubus spp.

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Where does one obtain concentrated (98% +) sulphuric acid in small quantities? Can it be bought from a hardware store? I'm looking to treat some seeds of an Indian Rubus sp. I've got and it seems treatment with sulfuric acid will yield the best results.

The seeds of blackberry and raspberry have a deep dormancy the restricts germination. Rubus seeds are normally enclosed in a hard seedcoat that restricts germination and they usually exhibit delayed or poor germination. Wild species are important resources for breeding, but little is known about their germination requirements. In order to better define germination requirements we examined two ways of abrading the seed coat to improve germination. Concentrated sulfuric acid and sodium hypochlorite (bleach) were used to treat the seed of 6 species of wild blackberries and raspberries. After treatment, the seeds were germinated in the presence of water, or chemicals known to stimulate germination in other seed types. One species had 14.5% germination in the untreated seed, but untreated seed did not germinate at all for the other 5 species. At 6 months all sulfuric acid treatments produced 50 to 100 % germination for 5 of the species, but one had very low germination (2 to 9%) on all treatments. Sodium hypochlorite was less effective for all species. The best germination with sodium hypochlorite was 36% to 49%. Some of the individual chemical treatments were more effective for certain species than just the acid or base treatments alone.

Technical Abstract: The genus Rubus exhibits morphological diversity and a wide range of reproductive systems and habitats. Seeds of blackberry (subgenus Rubus) and raspberry (subg. Idaeobatus) have a deep dormancy caused by one or more mechanisms. Rubus seeds are normally enclosed in a hard schlerenchymatous endocarp that restricts germination. Seeds of Rubus species usually exhibit delayed or poor germination therefore causing substantial problems for breeders. Wild species are important resources for breeding, but little is known about their germination requirements. In order to better define germination requirements we examined the effect of two scarification agents, concentrated sulfuric acid (98% +), and sodium hypochlorite (14%), on the seed of 3 species in subg. Rubus; R. ursinus Cham. & Schltdl., R. georgicus Focke, R. caesius L. and 3 species in subg. Idaeobatus; R. hoffmeisterianus Kunth & C. D. Bouché, R. coreanus Miq., R. occidentalis L. After scarification seeds were germinated in the presence of water, GA3, GA3 + KNO3 or smoke treatments. i controls had 14.5% germination, but untreated seed did not germinate for the other 5 species. At 6 months sulfuric acid treatments produced 50 to 100 % germination for 5 of the species. R. occidentalis had very low germination (2 to 9%) on all treatments and reached a high of 9% with sulfuric acid and smoke. Sodium hypochlorite was less effective than sulfuric acid for all species. Germination with sodium hypochlorite was 36% for R. caesius, but with GA3 + KNO3 was 49%. R. hoffmeisterianus increased from 12% with sodium hypochlorite to 33% with GA3 + KNO3. When R. coreanus was treated with smoke we obtained 43% germination. Germination in Rubus often continues for an extended period so this study will continue for an additional 6 months

Source.

From what I've read elsewhere, treatment can last for more than two hours. Does that seem to long in concentrated sulphuric acid?

Edit: correct spelling of sulphuric acid.

Edited by tripsis

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Jesus, that sounds like it'd be rough on the seed haha.

But to be honest, I'm really not sure where you'd find any sulfuric acid above 30% concentration.

You could distill the 30% H2SO4 provided you had the apparatus, but honestly, I really don't know anywhere retail that will sell at a 98% concentration.

However, I saw somewhere a while ago about someone saying that a particular brand of liquid drain cleaner is almost pure sulfuric acid.

Here it is:

I'm not sure whether you'll find that in Australia though.

The other option would be buying a small amount of reagent grade H2SO4 online, I'll see if I can find you a site.

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yes, as said, i would try pluming supplies, maybe they have it stronger than around the 30%.

it's very expensive, so maybe the local plummer can just give you a smaller amount, out of his bottle.

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Plumbing H2SO4 has lubricants and rust inhibitor added to it. I'd just go to a science supply.

And yeah, considering the conc stuff burns holes in paper, I would've said it is too strong, but hey. Plants are weird, and who's to argue with results.

Edited by naja naja

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empty out a few old batteries into an enameled container and set the vessel on top of a fire.

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and please wear safety glasses and apron and have sum bi-carb close by for splashes or such. Be very careful with the 98

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Hmm, maybe weaker concentrations would work then? I would have thought 98% is too strong too. Maybe I'll just give cold stratifcation and GA3 a go instead...

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Some of these ideas sound really dangerous! boiling anything containing sulfuric acid (especially with a view to increase its concentration) is not a good idea - if 98% is enough to burn through paper imagine what it would do if it bubbled up and splashed you.

Sounds like an interesting idea though - and Iv personally been keeping an eye out for sulfuric acid as well for other purposes, but it doesnt look like its going to be easy to get (at least not that strong and not mixed with all kinds of other things).

Also I think battery acid will have lead and lead oxides in it (as sediment), so batteries are probably not a good source

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Yeah, I'm going to avoid any ghetto teks to try to obtain strong sulphuric acid. Not even sure if it's worth obtaining it at all. The problem with the above abstract is that it gives the concentration needed, but not the duration of treatment. I've found other articles which mention duration, but not concentration. Two hours or more soaking in concentrated sulphuric acid seems like it would destroy the seeds to me.

Edit: spelling

Edited by tripsis

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Alright, here's what I needed to know. Depending on the subgenus, soaking the seeds in concentrated sulphuric acid can range anywhere from 20 minutes (for raspberries) to several hours {for blackberries). Information found here and here.

Now, what do you think this Rubus species is closer to: blackberry or raspberry? I would say raspberry based on the morphology of the fruit and how it is hollow like raspberries.

5661326216_37c46a5acc_b.jpg

Edit: spelling

Edited by tripsis

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You could try a 12-16 hr bath in coke rather than playing around with things that are likely to attract the kind of attention you dont want like lab grade H2SO4.

I know from esperance that it works Rubus fraxinifolius.

I'd probably stick with the original heavy duty recipe & not the diet, cherry or vanilla.

Edited by shortly

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Now that's a good idea. Did you also cold/warm stratify, or use any other method of breaking seed dormancy in conjunction with the coke treatment?

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No, just ambient temps.

R fraxinifolius is subtropical so it was only going through an animals gut that i hoped to mimic.

If your spp come from frosty areas i would probably stratify at least some of them after the coke.

Edited by shortly

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I thought that might have been the case, but thought I'd check anyway. Well, looks like I'll go get some coke to try instead. Easier and safer to get the sulphuric acid, though arguably less ethical!

Yeah, I'll cold stratify the seeds. Too cold to sow them directly now anyway.

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tripsis, i think thats a "too big turn around", first you are concerned 30% might not work, and now you are happy with coke instead? i think you guy's think too much in a mythical fashion, about the destructive forces of cola and it's properties.

if you are happy with using cola, which would not do anything, why don't you just use hcl instead? it's easy to buy, cheaper and much, much stronger than the acid in cola.

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My turnaround comes from my hesitancy in using a chemical as dangerous as sulphuric acid. I don't particularly want to have a bottle of highly corrosive acid sitting in my home, having no use except to for a few millilitres used to help germinate some recalcitrant seeds. With that said though, I would like to get the best results with these seeds and sulphuric acid seems to be the way to go.

I suppose I could give HCl a shot. What concentration and duration would you suggest? I only have a few seeds, so I don't want to kill them, just to aid them in germinating.

Edit:

I just called up Crown Scientific and they said you don't need a permit to buy H2SO4. The strongest they have is 90%. Unfortunately it only comes in 2.5L bottles, which will make for some very expensive seeds! Anyone need 2.49L of 90% sulphuric acid?

I would have thought it needed a permit? Apparently not...

Edited by tripsis

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i have no knowledge of acid treating seeds, i simply thoght you suddenly followed a total different avenue, and this could have harmed your project.

if the seeds are very special to you, maybe trying out an exotic tek is not the way to go.

i understand that acid stratification would save you a lot of time, but why don't you just go normal tek (5 moths wet & cold stratification and than sowing out, rubus needs it dark to germinate).

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I'm sure the powers that be would love to ban h2so4 since it can be used to make a heap of things they would rather not have getting about, but since every wet acid car battery on the road is full of the stuff its not surprising that isn't.

I dunno what it is in coke that helps seeds from soft fruit to germinate but I've been using it since i was shown in the early 80's & it does seem to work.

I actually spring for a can from time to time even though no one here drinks the stuff.

I doesn't seem to make any difference with really hard seeds like Acacias no matter how long you leave them and things like Opuntia need to stay in for 2 - 4 days.

Planthelper is dead right about not changing tack mid-treatment though, not with precious seed at any rate.

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Tripsis, I would try a longer soak in a more dilute solution of sulfuric acid.

98% Sulphric is whats called 'Fuming Sulphuric' and it actually gasses off 'smoke' when you open the bottle, this smoke is extremely corrosive as is the solution its self. Unfortunately because its so strong some damage is usually done by the time one washes with a basic solution.

Fuming Sulfuric is also very hygroscopic which means it absorbs moisture from the air very quickly, this is why its also has some applications as a drying agent.

All these things make is pretty impractical to concentrate your self unless youve got the right lab gear and experience.

If I were you I'd try some Sulfuric Acid based 'pH Down' from an aquairum or hydro supply store as this will be a much cleaner product, failing that try a chem supply house or some battery acid from supercheap, youll need to bring in an old refillable battery with you though, like from a mower or a bike/car.

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Alright, so getting 90% sulphuric acid would simply be too much money for me at around $70 with postage. If I use dilute sulphuric acid for a longer period of time, how long do you suggest Andy?

I believe it is the phosphoric acid in Coke that would help break seed dormancy.

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They also got improved results from sodium hypoclorite, which is just pool clorine from memory and bleach powder, surely that would be second choice. Just buy the H2SO4 from a lab supply house. The 100ml will prob be half the price of 20L :P

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I suppose it really ought to be. Easier enough to come by and still did alright.

Crown only sells H2SO4 in 2.5L quantities.

Anyway, I'm back at uni in a few weeks. I'll see if I can convince my old plant unit lecturer to help out. He liked me when I was doing the unit he taught, so hopefully he'll be willing to lend a hand.

Would be great to get some of these seeds to germinate!

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