Regarding that question, you might find interesting this review paper: http://link.springer.com/article/10.1007%2Fs11627-013-9547-3

Some highlights of what the authors mention:

" WUS is the only transcription factor that has been found so far to be involved

in regulation of both meristematic stem cells (pluripotent) and embryogenic stem cells (totipotent)."

"These results raise the intriguing possibility that mechanisms governing stem cell maintenance in vivo also regulate embryogenic meristematic cells in vitro."

I think it was the best answer (Gustavo Acevedo-Hernandez ).