Frédéric,
Voici ce qu'en écrit le site de Coimbra au sujet de la composition du milieu pour C. lunula...
C'est bien compliqué, en tout cas, je ne sais pas faire...
Par ailleurs, je ne vois pas pourquoi j'aurais à me décarcasser ! J'ai le prélèvement presque "at home" ! 
Preparation of liquid medium M7
- Stock solution (%) M7 (ml) 3
KNO3 1 10
MgSO47H2O 0.1 10
(NH4)2 HPO4 0.2 5
CaSO4 satured solution 10
Soil extract 1 - 20
Sphagnum extract 2 - 10
Distilled water - 930
Micronutrient - 5
1 Soil extract:
Weight 200 g of garden soil without great humus content, fertilizers or other protective agents. Add 1 liter of deionized water, and sterilize by heating for 1 hour.
Separate the decanted extract from particules by centrifugation. Fill into small containers of stock solution, autoclave for 1 hour at 1 atmosphere in three consecutive days. Store in the refrigerator.
2 Sphagnum extract:
Weight 50 g of dried Sphagnum, add 1.5 l of deionized water and sterilize by heating for 1 hour. Decant the extract. Fill into small containers and autoclave for 1 h at one atmosphere in three consecutive days. Store in the refrigerator.
3 Add vitamine B12 (5X10 -6 g) in sterile solution after autoclaving.
Composition of the micronutrient solution
- Stock solution (%) Micronutrient solution
ZnSO4 7H2O 0.1 1.0 ml
MnSO4 4H2O 0.1 2.0 ml
H3Bo3 0.2 5.0 ml
Co(NO3)2 6H2O 0.02 5.0 ml
Na2MoO4 2H2O 0.02 5.0 ml
CuSO4 5H2O 0.0005 1.0 ml
Distilled water - 981 ml
FeSO4 7H2O - 0.7 g
EDTA (Titriplex III, Merck) - 0.8 g
Autoclave separately two micronutrient solutions: Sol. I - 881 ml distilled water + stock solutions of salts whithout FeSO4 + 0.4 g EDTA
Sol. II - 100 ml distilled water + 0.7 g FeSO4 + 0.4 g EDTA. Combine after cooling.
Bonsoir
Yves
Sapristi, elles peuvent atteindre des tailles très respectables. 