The article where you reffering to is called:
Induction of Fertile Male Flowers in Genetically Female Cannabis sativa Plants by Silver Nitrate an Silver Thiosulphate Anionic Complex by H.Y.Mohan and R. Sett (Theor. Appl. Genet. 1982; 62(4): 369-375
It covers both STS (25, 50 and 100 ug) and AgNO3 (50, 100 and 150 ug) treatment.
Based on this paper, and other references (in this thread ) I repeated the experiment with a 50, 75 and 100 ug AgNO3 solution, and a 25, 50 and 100 STS solution. Aditionally I did a GA (50, 75 and 100 ug) treatment.
Clones (three to four internodes) where rooted for three weeks before treatment. They where then placed at 12/12. A 20 ul drop of test compound was apically applied each day for 5 days to make up the total amount.
The AgNO3 treated plants turned a bit black afer a week. They all recoverd thoug, and after (aprox.)three weeks both STS and AgNO3 plants plants produced male flowers. The GA treated plants didn't produce maleflowers, they just elongated a lot . After about five weeks the flowers opened and pollen was released. In pollenated donor plants, fruitset became apperrent in (aprox.) three weeks.
Although all concentrations of both STS and AgNO3 produced viable pollen, there was a significant increase in the number of male flowers in the plants treated with a higher concentration. The 25 ug STS solution seemed a bit low. Overall I think a 100 ug STS or a 75 ug AgNO3 solution gives nice results, but since a STS solution is prepared from an AgNO3 solution, and the 75 ug AgNO3 solution does not realy harm the plant, a 75 ug AgNO3 solution verdiend mijn voorkeur sucker!!

ExE=STS

Silver Thiosulfate Solution

i.e. Photography hypo and silver nitrate, materials approx. $30/gallon.

Commonly used in the cut flower industry. Application and disposal precautions apply.

Documentation:

Sex Reversal Techniques

from de Meijer, Ranalli, et al.

"All parentals used in this study were doubly inbred plants (S2's) obtained through the self-fertilization of selected female clones from the Cannabis collection of HortaPharm B.V., The Netherlands. The original plants had either CBD or THC as the predominant cannabinoid. The 00.45.1 clone was an exception, having both CBD and THC in significant amounts. The clones were obtained through in vivo propagation of lateral branches. An individual from each clone was partially sex reversed according to the procedure described by Mohan Ram and Sett (1982) and allowed to self-pollinate in isolation."

Just for some background info, HortaPharm is Robert Clarke's company, which has been working closely with GW pharmaceuticals in Britain over the last several years to develop truebreeding pure-THC and pure-CBD lines. It's also interesting that they use a method of sex-reversal based on neither gibberellins nor photoperiod. The title of the Mohan Ram and Sett article is "Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulphate anionic complex." Anyone familiar with this technique? (Chimera)

Silver Thiosulfate Solution
Preparation and Storage

Prepare a 0.1 M Sodium Thiosulfate (STS) stock solution by dissolving 1.58 g of Sodium Thiosulfate (Product No. S 7026) into 100 ml of water. Prepare a 0.1 M Silver Nitrate stock solution by dissolving 1.7 g of Silver Nitrate (Product No. S 7276) into 100 ml of water. Store the stock solutions in the dark until needed to prepare the STS.

In general, the STS is prepared with a molar ratio between silver and thiosulfate of 1:4, respectively. Nearly all of the silver present in the solution is in the form of[Ag(S2O3)2]3-, the active complex for ethylene effect inhibition.

Prepare a 0.02 M STS by slowly pouring 20 ml of 0.1 M silver nitrate stock solution into 80 ml of 0.1 M sodium thiosulfate stock solution. The STS can be stored in the refrigerator for up to a month. However, preparation of the STS just prior to use is recommended.

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Since several people seem to be interested in the preparation of silver
thiosulphate, I am sending this message to the list. Stock solution of
silver thiosulphate is prepared by mixing a 0.465 mM silver nitrate
solution (we add 0.079g of silver nitrate to 50ml of distilled water)
with a 1.865 mM sodium thiosulphate solution (0.295g silver thiosulphate
in 50ml water) (1:4 ratio). The silver nitrate solution is added OVER
the sodium thiosulphate solution, stirring continuously. We sterilise
the solution by filtration. Since the amount of sodium thiosulphate is much larger than that of
silver nitrate, all the silver is in form of silver thiosulphate and
therefore the concentration of silver ion is 4,65 mM in the final
solution. Actually the resulting compound is a complex ion
[Ag(S2O3)2]3-. We have tried from 30 to 120 uM of silver ion in the regeneration medium
and in all the concentrations there was an improve in regeneration
percentages. Optimum results were obtained with 30 or 60 depending on
the genotype.

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Preparation of STS
Stock Solution:
1. Mix 2¾ ounces anhydrous sodium thiosulfate or 4½ ounces prismatic sodium thiosulfate with one pint of water, stir until dissolved.
2. Mix ¾ ounces silver nitrate in a separate pint of water, stir until dissolved.
3. Pour the sodium thiosulfate solution slowly into the silver nitrate solution while stirring vigorously. This makes one quart of STS stock solution.
Application:
1. Mix two ounces stock solution with one gallon water.
2. Spray to run-off, one gallon covers 200 ft3 of bench space.
3. Apply early in the morning for maximum for rapid drying.
4. Applications should be made before buds show color.
5. STS is dangerous and should be handled by qualified personnel.
6. Store stock solutions in dark bottles under refrigeration.

----------------------------------------------------

Procedures for making silver thiosulphate
a. Dissolve 0.42 grams of silver nitrate
(AgNO3) in 0.5 liter of water.
b. Dissolve 2.48 grams of sodium
thiosulphate (Na2S2O25H2O) in 0.5
liter of water in a separate
container.
c. Add all of the silver nitrate solution
to the sodium thiosulphate solution
while stirring the mixture. If in
doubt about which way to mix the
solutions, mix them together quickly;
the resulting STS should be effective.
d. Dilute the resulting STS solution by
adding 9 liters of ordinary tap water
to give a total volume of 10 liters.
In most cases, ordinary tap water will
be acceptable. However, there may be
unusual circumstances in which
compounds in the water may cause
precipitation of the silver. The
presence of brown discoloration can
generally be used as a visual check to
indicate an ineffective solution.
e. Plants should be sprayed with
approximately 10 ml each. The 10
liters (2.6 U.S. gallons) should cover
1,000 plants.
f. Plants should be treated any time
after flower buds are visible, but
before first florets are open.
g. The dilute STS solution should be used
as soon as possible. If necessary, it
can be safely stored in a refrigerator
for up to one month. For longer periods
of storage, the silver nitrate must be
k kept away from light or in a dark
glass bottle.
h. All operations should be carried out
using glass or plastic containers.
Metal sprayers may be used if the STS
is sprayed immediately. Storage in
metal containers will deactivate the
STS solution.


References:

Galoch E. 1978. The hormone control of sex differentiation on dioecious plants of hemp (Cannabis sativa L.). Acta Societat is Botanicorum Poloniae, XI, VII:153-162.

Mohan Ram II Y and Juiswal VS. 1972. Induction of male flowers on female plants of Cannabis sativa by gibberellins and its inhibition by abscisic acid. Plants, 105:263-266.

Mohan Ram II Y and Sett R. 1981. Modification of growth and sex expression in Cannabis sativa by aminoethoxyvinylglycine and ethephon. Z. Pflanzenphysiol., 105:165-172.

Mohan Ram II Y and Sett R. 1982. Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulphate anionic complex. Theor. Appl. Genet., 62:369-375

wiemzenicniewiem pisze:

pytanie do fubara ;) ktoś mi powiedział że takie nasiona dadza sporo hermow, jak to mozliwe?

podobno przeciez nie da sie zmianami fotoperiodu wywolac hermienia u 100% zenskiej rosliny, jesli zapyli sie ja żeńskiem pyłkiem, powstana znowu zenskie nasiona, dlaczego mialyby sie hermic?