laughing gas to make tetraploids?

Saw a very small article in a Horticulture magazine the other day – said that dutch tulip growers use laughing gas to double the chromosomes in their tulips and that it was safer and more effective than cholchicine. Anyone know anything about this? I am very tempted to ask a dentist I know if I can try it.




Here’s a patent application for a nitrous oxide-based method for doubling chromosomes:




I was looking at sites for nitrous oxide sales. Apparently, small amounts are sold by food distributors for whip cream in little pressures canisters. I suppose those could be used for personal experimentation. Not sure how, but it’s a start.


Just thinking out loud. Lets say I go to a Goodwill or Salavation Army Store and buy the largest used pressure cooker that I can find.

Then I have to find 2 common chemicals that when mixed together produce nitrous oxide. Any suggestions?

The patent article seems to favor introducing the plants to the gas before fertilization while my second link first fertilized and then introduced the gas, any comments?

Can anyone answer the following? Could one put cuttings without leaves into the gas chamber and then expect that the buds (that we take from the cuttings and graft on to understock) would produce plants with doubled chromosomes.?

The classic way to make nitrous oxide is by heating ammonium

nitrate, but ammonium nitrate can explode and I wouldn’t try it.

The link below describes a way to make it from three easily

obtained chemicals, urea, nitric acid, and sulfuric acid.

2 (NH2)2CO + 2 HNO3 + H2SO4 → 2 N2O + 2 CO2 + (NH4)2SO4 + 2 H2O

They dissolved powdered urea in sulfuric acid, then gradually added

the nitric acid. The preferred temperature for the reaction was 60-95

Another thought - you can buy kits for injecting nitrous oxide

into car engines for short-term increases in horsepower. Maybe

high-performance car supply stores would be a good source for

nitrous oxide and the equipment to handle it.

Internet source for nitrous oxide bottles (24 for $14.95).


I’m always looking for oversimplified instructions before I look at more detailed info. Basically, what does one do? How do you create the conditions. Its getting intresting.

Enrique, you put the plant in pressurized nitrous oxide for 24 hours.

Hey Jim… But how? Does one need to purchase specialized equipment? And what method does one use to messure PSI? I’m trying to think of a few ways-- Maybe the inside of those big yellow chemicle pump spray is ideal. That’s one thought for the mean while. Another method I’m thinking is putting the little seedling inside a ballon, and filling it up with the whip cream dispenser thing. But retrieving seedlings would be a problem, wouldn’t it? Popping the ballon could harm seedlings. And I see the small opening of a ballon as a difficult task to put a small live seedling. Maybe a condom, or a rubber glove could do. I don’t know.

A few may remember, I had Bishop Darlington in icy water for about 2 days trying to cause tetraploidy in it. Well… the thing died, although it survived long enough to put new growth. So it’s back to the drawing board again. But I do have good news still, My rugosa Rosarie d’l Hay (spelled wrong) maybe a tetraploid. I’ve told people in the past that its foilage was different, but the pollen of it was very infertile. But branches that originated as DMSO/preen treated buds are forming hips very easily. So-- I am very sure that something has gone good for me once.

Enrique, yes, you need specialized equipment to handle high pressure. There are pressure gauges for measuring psi. You can see them on air compressors, among other places.

I don’t know whether balloons, sprayers, or pressure cookers can contain enough pressure to be effective. The researchers in one of Henry’s links mentions 90 psi. I don’t know how much pressure a balloon can contain. I’ve seen references to using sprayers at pressures from 10 to 60 psi, depending on what you’re spraying. The spray tanks are no doubt designed to handle somewhat more than 60 psi. Pressure cookers are designed for 15 psi and have a safety valve that opens if the pressures rises above that. So it seems that a heavy duty spray tank might be a good thing to try. Or maybe one of those old-fashioned fire extinguishers?

Congratulations on your Roseraie de l’Hay! Please keep us posted on it.

The patent article starts at 100 KPa. 100 kpa is equal to 0.987 atmospheres = 14.5 psi.

The pressure cooker normally is set for 15 psi. I would expect that a small molecule gas at that pressure may take longer to penetrate but, once in the plant, would have the same effect as at a higher pressure.

I assume that the best way to get the nitrous oxide into the pressure cooker would be to drill a hole and tap it for threads that would take a fitting from the automobile nitrous oxide unit. I would probably apply epoxy to the threads as a precaution. A valve on the input line could be used to prevent the gas from entering too fast and blowing the pressure cooker relief valve off the pressure cooker. The valve would also help control too rapid a cooling due to the gas expansion.

Of course, I would only use the unit outside.

That sounds well worth trying Henry. Please let us know how it works if you do try it.

My 2 gallon sprayer (RL Flowmaster PGX) has a pressure relief valve that opens at 45 psi. I think I can introduce the nitrous oxide via the hose. If 45 psi isn’t enough, there is a backpack-type sprayer that is advertised to be capable of 180 psi.


Here’s another question. Does one keep the seedlings on a soft medium or something to keep them from drying out? This is getting very intresting. Very intresting.

Enrique, it probably depends on how long you leave them in the pressure chamber. The patent application covers periods of time from 3 hours to 6 days and pressures from 100 KPa (15 PSI) to 1400 KPa (2100 PSI). The specific examples in the patent application were for 2 days at 90 PSI. Presumably, if you use a lower pressure, you would need to treat the plants longer, and there would be a greater risk that they’d dry out.

Did anyone try this method and get results? Tubless tire would be a good chamber for me. High presser gas is danger big time.

Is someone volunteering to risk blowing themselves up with a whipped cream syphon?

The container has a capacity of about 750 ml and is designed to hold 500ml of liquid. The N2O chargers hold 10 cc of N2O by volume. Wikipedia says each holds 8 g under pressure. Given water and air already in the container, the calculation of the psi inside the container is beyond me. I have no idea how much pressure the container is designed for, but I’m can say with assurance that the manufacturer never intended it for this use.


Whipped cream used to be made with compressed CO2 half a century ago when I was working in a coffee shop, but nitrous oxide amounts to the same thing. With 24 L/ mol at 1 atm (15 psi) and the mol wt of N2O = 44, 8 g will get you 3 L or so to 1 atm. Or 3/4 L to 4 atm = 60 psi. That sounds a little high to me when you throw in the water/cream. But you’d need to look up the N2O solubility in those to figure how hi the headspace pressure might be.

A bicycle pump obviously will handle, and produce 60 psi. The tire idea sounds OK but for the large volume compared to what you need. Pressure cooker is OK too- replace the blowout plug with your pump inlet and depend on the weight of the 15 psi usual jiggler on top, to keep things at 15 psi. But probably a cheap sprayer is the most convenient thing. With mine the hose of a bike pump fits in the tube that takes the nozzle. So I can blow junk out of the line back into the tank, while holding open the spray control valve. You could do the same and just keep pumping until you reach say 50 psi, then close the release valve. The tank will hold for days if properly sealed.

I think Henry is right that the pressurization is just a way to increase the concentration of the gas so it diffuses a bit faster. But really you can get the same effect by using smaller tissues as the subject. Someone ought to try flower buds to see if they can make tetraploid pollen. Maybe 2-5 days before pollen shedding? I don’t know the development cycle well enough to say. Cut off the petals to facilitate diffusion, maintain the bud in a happy state after treatment, perhaps with the stem in some 1 % sucrose in a tube.

Drying out is little problem in a closed container with moisture present. Once you reach 100 % humidity you stay there.

Decompression is the most dangerous part of all for the plant. The release of overpressure can rupture cell membranes if bubbles expand. Pollen is tough, but not all tissues are.

Germinating seeds might work well too, if you catch them while they are making the apical meristem very active, while the achene is coming open for instance. Or better yet, while using the water germinating technique of George. But I might go for a low dose of oryzalin in the water rather than a shot in the dark with nitrous oxide.