scarification of opuntoid seeds

[Jens]

I did scarification of half of the opuntoid seeds I sowed on March 14th in plastic bags.
Nothing happend in the intact seeds pots. But scarification really speeeded the germination up.
Maihuenia patagonica (labeled it wrong in the pot)thanks for them Christer!
The first look I took after 6 days


I transplanted the germinated ones right away and put some fungicide (Chinosol in the new water)
Next time I will have to treat them before sowing.

Pterocactus kuntzei of my own harvest.
I chopped off the top of one of the seedlings- he doesn´t mind so far though

[Jens]

The last of the four scarificated (is that the right word?) Pterocactus seeds in the pot sprouted now.
The other pot with intact seeds showed no movement of the seeds yet.

[promethean_spark]

That's my experience with mahuenia as well. 0% without scarification, ~50% with scarification.

[Jens]

Interesting,
a technical problem with cutting into Maihuenia seeds was that they snippped away to the side when I was trying to cut into the smooth black shell.

How do you do it?

[daiv]

Jens,
I learned from CactusJordi that he puts a piece of clear plastic over the seeds when they first germinate to force that big long root down into the soil. I sowed G. pulchella and all but one dried up on me.

[promethean_spark]

I just press the seed against emery paper with my fingertip and rub it back and forth until the black coats gives way to a tan colored lower layer.

[CoronaCactus]

To help to keep the seeds from flying across the room I cut small 1" strips from a rubber band and wrap half the seed in it then pinch it with tweezers and sand it down. If cutting or knicking, I'll use a set of locking forceps to keep a good grip on it.

I've also tried the freeze/thaw thing, but haven't combined sanding, knicking and freeze thaw all together though. My success has still been sporadic my best success was with fresh habitat seed. I did nothing but sow them and to my amazement they germinated in just a few days!

What methods have you been using, Jens?

[Jens]

Thanks for the advice guys that´s all usefull things to employ.
I tried to rubb the seeds of Puna subterrranea, Miqueliopuntia miquelii, Mahuenia poeppigii and M.patagonica on sandpaper by holding them with two fingers -but in half of the cases I lost the seedgrain by twitching it out of sight. , Then I tried to cut into them with a scalpel and twitched away sonme more (especially the Miqueliopuntia miquelii were tough as hard wood). The I used a woodcarving cisel for cutting with best results. Although in some cases I cut the seeds almost in half they still seemed to germinate good.
Today I tried to squeese and crack the shell of Maihuenia with a forceps and sowed them after powdering with atiram.(Lost only 1 of 8 by hoppping away )
I tried freeze and thaw in the baggy for about 3 weeks with maihuenia poeppigii seeds from habitate (ordered from Juan Acosta)- but so far none germinated after 2 weeks in the propagator. Maybe I will try to take them out and make a cut in the shell ?!?

[CoronaCactus]

Need to work in a bubble not to lose airborne seeds

Have you tried soaking them in water or water and an additive after chipping/sanding before sowing? I'm going to try this next time. I've never combined all methods at once, so I'm curious what the results will be.

Another method is to use an old blender and blend the seeds with coarse sand and small gravel. Basically an advanced sanding method.

[iann]

It's quite safe to grip Opuntia seeds with pliers and hack away. The seed itself is tiny and dark brown, so keep an eye out for it. All the pale coloured bits are just aril and you can do what you like to those with no risk.

Non-Opuntia seeds can usually be pricked open with a small needle or pin. If you flick from near the hilum towards the pointy end of the seed, the end cap will come off. If you did it right the end of the embryo will be sticking out but undamaged. Don't try this with Lithops seed

[Jens]

Hi Darryl, and Ian, lots of good informatian to work through the tough opuntia seedcoats. I should try soaking the seeds before putting them into the substrate. How long would you recomend to soak and what kind of additive did you have in mind?

At our local cactus club meeting we just had a talk about Sclerocactus and Pediocactus. The guy also propagates them from seed and he is using concentrated sulphuric acid for 20 min on the seed coats with very good results. (After acid treatment he waters shortly to neutralize and than sows them right away.
Ever tried that on other species?