GUS staining

[user unknown]

Hi, everyone:
	I have a little problem in gus staining.   What I did is staining 
the young tomato leaf/cotyledon with GUS ( 5mg X-gluc disolved into 200ul 
Dimethylformamide, add into 5ml 50mM phosphate solultion, vacuum for 
20 min, stain at 37dgree C for 16hrs.).   My problem is the 
leaf/cotyledons are not stained uniformly.  While some specks/areas are 
heavyly stained, other part are not blue at all.   
	I wonder if anybody can nicely give me any suggestions to improve 
my staining.   If you have any successful experience, PLEASE HELP.

	Thanks in advance.


		Yusen Tong