design: Opium poppy cultivar HN1 seeds were sowed in soil mix containing potting mix, vermiculite and sand with 2:1:1 ratio, and grown in plant growth chambers with 14 hours light and 10 hours dark at 20C and 93% humidity. Six different tissues including leaves,ems (2-4 cm below capsule), capsules, petals, taproots and fineroots of opium poppy plants at one-day post anthesis were harvested for ATAC-seq and RNA-seq experiments.  _x0000_