Abstract: The wide-distribution species Solms-laubachia eurycarpa on the scree on Baima snow mountain was used as the experimental material, and the suppression subtractive hybridization (SSH) based on magnetic beads technology was used to isolate the differential genes between day and night. After randomly sequencing 136 differential ESTs, these ESTs were further analyzed by functional annotation by Blast2go. Our results show that most ESTs are related to cellular homeostasis and stress response, followed by material and energy metabolism, and signal transduction. The process of S-L.eurycarpa responsive to daytime environment is very complicated, which lays a good foundation for further studying alpine plants adaptation to harsh environments of scree.

Key words: differential expression, EST, Solms-laubachia eurycarpa, suppression subtractive hybridization(SSH)