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Germination and storage of acacia seeds..

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jamie

jamie

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Okay so I have ordered and received a number of acacia seeds now..including..

Acacia Obtusifolia
Acacia Acuminata
Acacia Floribunda
Acacia Confusa
Acacia simplex

I am guessing I can germinate them in a similar way to how I do Mimosa Hostilis? I have never had a problem with mimosa germination so I hope these acacia trees will be similar..

More importantly though I want to know hwo to store them? Can I freeze them? I have more than I need to start with and I dont want to use them all right away becasue if one method of germination is not so good I want to have some backup seeds..with mimosa and caapi I have both had success freezing the seeds and germinating like 4-5 months later..so will acacia seeds remain viable if I freeze them? Will some of them stay viable while other species will not?
 
..the hard coat of acacia seeds are designed to last a long time..stored airtight, cool and dry, most will have at least 10 year viability..seeds of many species are known to last 50 or more years in soil..Acacia melanoxylon seeds were still viable after 20 years in sea-water! ..at least 5 years shelf life would be expected from all the species you listed jamie..

..my germination method is to place seeds in water, bring to a boil over 5-7 minutes, then soak 24 hours till slightly swollen...
 
Okay I got one acuminata going in a window under some grow lights and started bringing it outside for a bit on the real warm and sunny days and just sticking it with my mimosa trees..but I had some trouble with the confusa and obtusifolia.

I of the 2 confusa seeds that did sprout from the seed coat and start to get some green on the leaves died from rot after a day so I got some peat pellots instead which seems to drain better than what I was using. I germinated 2 more the other day by nicking the seed coat and soaking in some boiling water for the night. I put them into the peat pellots and them into a germination chamber for humidity under a grow light.

Today I removed the sead coat on one of the 2 confusa seeds and put it back into the peat just to see the difference..It seemed that with the obtusifolia it took too long to break the seed coat and so they rotted and so I figure this will help spead things up..but I know that the sead coat also helps it stay protected from diseases as well as a seedling so is this a bad idea?

I have probly 30 confusa seeds left, at least 20 acuminata and floribunda seeds so I am not worried I will get enough of them going..but I have only 3 acacia simplex seeds and 6 obtusifolia seeds left, 3 of the barrington tops and 3 of the ones just labled obtusifolia..so I dont want to mess up with those ones..

I going to try a few different things with the confusa I guess and get a few more acuminatas going, then floribunda..and then try again with the obtus and simplex once I have more experience.

Acacia does seem to require a little more attention than mimosa in my experience..but I got 1 out of 2 acuminatas going, and 1 out of the 2 confusa's until I drowned it..so that is like 50% success at getting those ones to put out roots..

The acuminata has been growing a bit more each day so that is good :)

I am using a mix of sand, perlite and soil comprised of peat and humus..does that sound okay for acacia trees? I have my mimosa trees in the same and they do okay so I figured acacia would as well..
 
..acacias are very sensitive when young..need to be handled carefully..usually 30:70 peat/sand mix good for seedlings..
re germination..it is better to either boil OR scarify ..some people prefer to scarify (damage coat, not all of it)
..I personally do the boil thing as described above..leave them soaking in cold water 24hrs..they should increase size/swell..if not, either be patient or repeat brief boil..i sprout on tissue, then very carefully place in sand/peat mix..they can't be allowed to dry out when little, but too moist a mix is not good..maybe good to heat sterilize the medium which lead to rotting..
 
okay cool nen thanks!

It looks like I might have a second acuminata starting to root but I am not fully sure yet..and looks like a confusa is sprouting as well now..
 
nen888 i have a totally different philosophy to you!

it sounds rough but i deliberately neglect my acacias, esp. at the seedling stage. imo really the worst thing a cultivator can do is nurse weak genetics. i'm not sure if there's as strong a relation between env. stressors and alkaloid production as in cacti, but really it's a waste coddling a plant in a place it doesn't belong



these are at ~4 and 5 months old
ng38ck.jpg

fjne5v.jpg

these were collected from a maiden's wattle verified through multiple experiences to be high in tryptamines, seems there's only 1 possibly 2 that will make it to maturity. broken dreams but strong genes
 
..good approach for toughening up, seldom, interesting..
in terms of people trying to get maximum mass quickly, what gets acacias to grow is rain..they're not quite like cacti..so, with the more mollycoddling method, I would usually expect to have 5 month seedlings at least a few inches high..I have grown acacia maidenii x obtusifolia to 6-7th in 3-4years with regular water, nutrient and sun..the alkaloid content was higher than most wild plants which are less watered..stress may slightly increase alms in acacias, but I don't think by a lot..seems more seasonal orientated..in the wild it can take 10-15 yrs for trees to reach 6th if there are long dry periods..
..on the other hand, it is good to have plants that will survive in harsh conditions with no assistance, so keep up the work with those super 'toughies'..good to have 'plant and temporarily forget' varieties..
 
well, I dunno how fast acuminata is compared to other species but mine is doing fine outdoors here with what I have been doing. It is nearly as developed as those plants pictured above in just 2.5 weeks or so..I took it outside about a week ago and it does not seem to mind.

I notice that a few of my mimosa trees origionally did not put out much root beyond the tap root..and those ones never quite took off..while most of my other mimosa trees put out tons of roots and got rootbound and needed noew pots..those trees have also grown alot more than the other trees in the last year and are starting to develop a woody trunk like stem with bark.

I dunno if it is genetic or what that push a tree to node alot along the roots like that, but those are the trees I chose to really grow out to maturity.
 
only thing i could add roots generally spread in response to a lack of water, not an abundance of it, so it may be related to that
 
no I dont think it is that..I tried that with them..

8 of the 12 mimosa trees I planted grew to a few feet tall in less than 1 year..the tallest is maybe 4 feet right now..the 4 that did not put out full roots are only like 8 inches tall...

Might repot that 4 and feed them some ferts and see how they grow over the summer..the other ones are loving the warm weather now and are putting out new growth so hopefully that other 4 follow..
 
got this PM from Lago Chiller..they could not post in this section yet..

"From my supplier of acacia simplex seed 4 out of 5 going strong.:
To maximize germination of these expensive seed: Nick seed lightly with a file - just abrade the surface and don't go all the way to the quick - then soak for 15 minutes in a solution made of 1 part household bleach and 8 parts water. Rinse them well. Fold a paper towel into quarters and moisten with distilled water. Squeeze out excess, so it is just damp, and put on a clean plate. Put the seeds (nicked side down) on the towel and cover with plastic wrap, leaving an air space above the seeds. Keep in a warm place (70 - 80°F) and inspect every day. Any seeds that don't swell in a day or two should be re-nicked and re-sterilized. Any seeds that develop mold should be removed and re-sterilized and put on a separate plate - most of these will sprout, too, but this keeps the others clean. When the roots are a half-inch long, plant the seed in a light, well-drained seed-starting mix, and keep warm. If you have had trouble with these in the past, try this method and you are sure to be successful! This method gives high germination."

So thank you Lago Chiller!
 
..most species you can just damage the hard outer coat with a pair of scissors (without damaging the internal germ) and then soak for a few days, bleach not essential..swelling (& slightly color change) are indicative that sprouting is beginning..this method (in my exp) can take a week or two
..i've just found in personal experience with Australian species that the 10 minute boiling method has a slightly higher germination rate, and is usually quicker (a day or two)

..Asian and Pacific species like A. confusa and A. simplex may not have the same fire tolerance adaptation as australian (& some african) species, so scarification (damaging) probably is the safest option..and bleach (as reported by Largo Chiller) would prevent rotting, as was described earlier..
.
 
Effect of boiling water, seed coat structure and provenance on the germination of Acacia melanoxylon seeds

www.publish.csiro.au

Effect of boiling water, seed coat structure and provenance on the germination of Acacia melanoxylon seeds

Acacia melanoxylon (Mimosoideae or Mimosaceae) is a high quality timber tree with an extensive natural distribution in Australia and a wide genetic and phenotypic diversity. Seeds from three widely differing provenances in Tasmania were tested to determine whether they had different responses to...
www.publish.csiro.au www.publish.csiro.au
Abstract
Acacia melanoxylon (Mimosoideae or Mimosaceae) is a high quality timber tree with an extensive natural distribution in Australia and a wide genetic and phenotypic diversity. Seeds from three widely differing provenances in Tasmania were tested to determine whether they had different responses to various dormancy-breaking treatments. All provenances had limited germination (<11%) if seeds were untreated and between 85% and 91% germination after 40 days if the seeds were nicked. For all provenances short (≤60 s) exposure to boiling water gave high germination percentages. These values were generally lower, although usually not significantly so, than the germination percentages following nicking. Germination percentages decreased with increasing time of exposure to boiling water, although one provenance had a significantly greater tolerance to one of the longer (20 min) treatments. Nicked seeds germinated quickly and uniformly, whereas those subjected to the boiling-water treatments germinated after a longer period and more gradually. In untreated seeds, the lens was a low, elliptically shaped dome (~110–135 µm wide, 140–190 µm long). In more than 99% of the seeds examined, the structure of the lens was markedly altered after a 10-s exposure to boiling water. A wide diversity of altered lens structure was found, from a circular hole between the macrosclereids, to a short fissure where the macrosclereids did not separate to their bases. Nicked seeds had a 200–375 times greater area for water uptake than a fully disrupted lens and this was probably the principal reason why the nicked seeds germinated sooner and more rapidly.
Click to expand...
 
I've been having excellent success rates germinating tropical Acacias (confusa & simplcifoia) recently using 35% H202 as a pre-treatment, I typically get over 90 % to grow. It also works well for Mimosa hostilis and I get over 90% of them to grow too.

First I give the seeds a quick rub on a sheet of sandpaper, just enough to remove the tough waxy skin and then I soak them for 15 minutes in the hydrogen peroxide. Then I rinse them and put them in jar of warm water (about 60 deg C) and let them soak overnight. Then I drain the water and rinse the seeds and then put them back in the jar with just enough water to cover them and tiny bit more to allow for evaporation so they never dry out. I change the water at least once a day for three days.

After that I plant them in a good quality seed raising mix and put them in full sun.

The Mimosas will typically germinate in the water in about three days (in warm weather) and the others germinate in less than a week after planting.

Since I started using the H202 I hardly ever have any develop any fungal problems, the H202 also helps to break down the seed coat so they can take up water.

All the tropical Acacia species seem to love it hot for good germination and I get the best germination rates in hot weather - 30 deg C and higher.

I find that A. acuminata doesn't like such an extended soak and I'd only ever leave them soaking for 2 days at most and they really need boiling water or nicking to break their dormancy.
 
Studies and research was conducted evaluating the most effective methods for germination of Acacia seeds. This included:
1) Water (control)
2) Boiling water soak (10 mins)
3) Sulphuric Acid soak (1hr), follow by tap water rinse
4) mechanical scarification

A general conclusion was that for the species with the larger seed weight, the highest germination was achieved using sulphuric acid, and for smaller seed, the highest germination was achieved using scarification and boiling water.

When using the boiling water method, generally plants with smaller seed only need soaking of no more than 1 hr, where the larger seeds can be soaked overnight (up to 24hr)

Reference: Ghassali, F., Salkini, A. K., Petersen, S. L., Niane, A. A., and Louhaichi, M. 2012. Germination dynamics of Acacia species under different seed treatments.
Range Mgmt. & Agroforestry 33(1): 37-42

Another method that is well known to increase the germination percentages of many native species, is using "smoked water". Smoked water is a PITA to make IMO, as you need special equipment to push\pump the smoke into the water.

One way you can add a spin on this, is to use smoke and vermiculite to make.... "smoked vermiculite". To make this, just place some wet vermiculite on a sieve, sitting over the top of smokey fire for around 10-20mins. Place some of the vermiculite on the top of your soil, and when it is watered, the chemicals will reach down to the seeds.
 
.. follow up to --Shadow's post with a recent article published online in the Journal of Biology, Agriculture and Healthcare. The paper experiments with various pre-treatment methods on Acacia senegal. The paper suggests "soaking the seeds in 50% concentrated H2SO4 for 15min or circumference scarification of the seeds before sowing reduced the time taken for the seed to germinate and gave high percentage germination "

Attached

Zubairu, S.U. 2014.The Influence of Seed Pre-Treatments on Seed Germination and Seedling Vigour in Acacia senegal in the Nurs. The Journal of Biology, Agriculture and Healthcare4: 57-63
 

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