Abstract：To study cis-regulatory elements in AtEXPA1 (Arabidopsis thaliana expansinA1)promoter，a full length of 897 bp genomic fragment and a series of end deletions fragments, isolated from Arabidopsis genome by PCR, were fused to the beta-glucuronidase reporter gene (AtEXPA1::GUS) and transformed into Arabidopsis leaves by particle bombardement and tobacco protoplasts by PEG-mediated method , respectively. The results of histochemical GUS staining and fluorometric measurements showed that some enhancing transcription elements existed in -144bp to ATG. We treated protoplasts with external stimuli including light, cold, abscisic acid(ABA) and salinity. Quantity analysis of GUS activity suggested,(1)some regulatory elements response to light widely existed in AtEXPA1 promoter;(2)-897～-626bp contained negative elements response to cold;(3)-626～-444bp contained negative elements response to ABA;(4) -626～-282bp contained negative elements response to salinity.
