mastersianum sowing

[Paul]

Hello,

I've tried last year to sow seeds from my mastersianum and had good germination on 1/2 Orchimax medium (= P668 with banana, vitamins, hormons... )
But only reach protocorm size (green), and even when replating, no growth and then it turn brown more than 6 months later!!

Is there a special treatment (medium, additives) for replating this species?

thanks
Paul

 

[Rick]

Paul

I don't know what Troy Meyers uses, but the first time I sent him seed, we were able to get a small flask of seedlings out of it. You might check with him to see what he did then.

Otherwise he's been having similar problem with the most recent mastersianum seed I sent.

He also remarked that they produced lots of roots with very small leaves (which is how they were when I first got to see them).

I hope Eliseo can throw in on this. He's been experimenting with flasking media, and made one based on K-lite (there is a thread of early results posted).

 

[PaphMadMan]

But only reach protocorm size (green), and even when replating, no growth and then it turn brown more than 6 months later!!

He also remarked that they produced lots of roots with very small leaves (which is how they were when I first got to see them).

No experience or particular knowledge of Paph mastersianum, but based on general plant tissue culture experience I would say both of these problems could be hormonal. Once induced a growth pattern may be hard to change, so even well after replate it could be be from hormones in germination medium.

Could be from hormones added, or lack of hormones needed, or from hormone activity from complex organic constituents of media. Makes it hard to track down, but it could be a starting point.

 

[Rick]

Could be from hormones added, or lack of hormones needed, or from hormone activity from complex organic constituents of media. Makes it hard to track down, but it could be a starting point.

Given the success I've seen growing this species on just less of everything, I'd work on the assumption that it's getting OD'ed rather than starved.

 

[Trithor]

I suspect the problem might be light levels. I have found problems with arrested development after the protocorm stage resulting from singly or combination of the following;
Light levels too high ( can happen just by simply increasing the spacing between the flasks)
Medium becoming dry as happens with long germination times
Gel strength too high
Changing the flasks position ( I have noticed this with some species, when I inspect the flask, and perhaps move it, the protocorms stop developing, while flasks that remain undisturbed continue to develop)
Some species prefer simpler germination media, I suspect banana and hormones may play a negative role here.

If you still have seed available, I would prepare three or four germination media variations, and reduce the light levels. I often plate to three different variations and although on easy species get germination and progress on all three, on the more difficult ones I only see any success on one. I use half strength Knudson without charcoal, Third strength M&S with charcoal and coconut water, plain coconut water with added sugar and ammonium nitrate, and a variation of Svante Malmgren. These four form the basis of all my mother flasks.
I have not tried mastersianum (unfortunately), but I am starting to have pretty fair success with quite a large number of other species.

Good luck

 

[Paul]

Thank you for answers

I think next time I could try with different concentrations and media. 1/4 MS could be tried, or why not kelp extract + ammonitrate + sugar?
My plant responds very well with that as it should produce two spikes in spring
Maybe I have replated too late... not easy to know but Paphs are more sensitive than Catts I also sow

another thing to try could be sowing with no agar, and replate only when protocorms are green. I think Xavier was doing this way with Paphs, working very well!

 

[eteson]

No experience with this species but I would think that the problem is too much agar in the medium as was pointed by Gary. Try P668 at 1/2 + banana (30gr/l) and very low agar concentration (the minimum to keep the protocorms on top without sinking).
I am having good results with maltodextrine + agar as gelling agent because this mix allows a very good diffussion rate of nutrients in the media.

As said by Rick we made some experiments with a medium based in klite and the first results are very very good in Paphs and Phrags. Hope to have time soon to re-take the experimentation.

 

[myxodex]

I've been setting up to try seed sowing myself (second attempt) and came across this paper on P ciliolare http://www.researchgate.net/publica...ts_of_Paphiopedilum_ciliolare_Pfitz._in_vitro.

In addition to the above paper the general picture I get from a few other papers is that some difficult orchid species can be sensitive to the major salt mix and reducing the salts was the key, which is in line with what Rick is suggesting.

Also bear in mind that adding large volumes of organic supplements like banana and coconut water are adding a surprising amount of additional salts. For example 30g/l banana is adding about ~100 ppm K and coconut water at 30ml/l is adding ~75 ppm K and ~32 ppm Na, and so even if you are only adding 10g/l it is still a lot extra if the major salt mix is already too high and the species salt sensitive.

In the linked paper they found a slight inhibitory effect of IBA on development. I seem to remember (perhaps wrongly ?) something about IBA and NAA not being naturally broken down by plants, which makes them more powerful, and hence popular choices in horticulture, rather than the natural IAA, which is unstable and involved in some sort of regulated feedback that can be more easily terminated by the plant's biochemical regulation. I think one of the major suppliers of P668 adds NAA.

So although I only have the experience of a failed first attempt (didn't replate to different medium on time), what I'm reading is in agreement with what Rick and Trithor are saying, it seems less can be more. The book I have on the basics of orchid seed propagation by Seaton and Ramsay they do mention a very simple germination medium which is just 0.75 ml Maxicrop per litre (not sure it's suitable for replating).

 

[PaphMadMan]

... I seem to remember (perhaps wrongly ?) something about IBA and NAA not being naturally broken down by plants, which makes them more powerful, and hence popular choices in horticulture, rather than the natural IAA, which is unstable and involved in some sort of regulated feedback that can be more easily terminated by the plant's biochemical regulation.

Mostly correct. IBA does occur naturally in some plants, and I would assume those plants can regulate it and break it down. But I'm not aware of evidence that it is natural in any orchids. Both IBA and NAA are more chemically stable and biologically persistent than IAA, and more strongly stimulate rooting and other auxin-mediated effects.

As an example of what too much auxin activity can cause, consider 2,4-D herbicide.