hii Kristina ,

You plz follow the protocol referred by Prof. Dolezel in Nature Protocol. There are several isolation buffers you have to check first and if your plants contain large numbers of secondary metabolites (polyphenols, flavonoids etc.), it will interfere with the PI fluorescence hence lowering the CV.  So, for that you can use 1% PVP or b-mercaptoethanol. You first try with those protocol, if those doesnt work, you may go with the HPI lysis buffer protocol. You can send me a mail, so that I can send the papers and protocol.

Cheers,

Biswajit

Thanks. Which standard did you use? We adjusted the settings of the machine, now it looks ok with DAPI.

Just to confirm - since we find di- and triploids: 2,64 pg is the triploid DNA content?