I tried several times to sterilize D. cistiflora, however, it seems that it is
EXTREMELY sensitive to Sodium hypochlorite.  I sterilized leaves for 5 min. in
a 5% solution as well as a 2 1/2% solution.  Everytime the leaves just turn
brown.  Is there a better way?  
Can you also tell me what Na2EDTA does for the plant?  Is it necessary for a
Knudson C based medium?
Christoph