tissue culture

[Russell Poulter]

Hi,
	I am currently attempting to grow some Nicotiana in tissue culture,
with the intention of doing leaf disc transformations. However, my leaf discs
are curling up, and therefore only growing in the areas which are in contact   
with the media. I am growing them on MS medium using various levels of NAA and 
BAP. The pH of the media is correct prior to autoclaving (pH 5.8). In the past 
they have grown properly, though I don't know what I am doing differently now.
	Has any body out there come across this problem? Did you find out what
was going wrong?
	HELP!!
		Nick Holton
		University of Otago
		NZ