Chlorophyll fluorometry has also been used for the quantitative evaluation of drought survival . Especially the luciferase screen with its very brief response time could be employed to test for transient inductions. This system has been applied in stress or ABA-related mutant screens , as properly as in circadian rhythm associated mutant screens [82-84]. Forward genetic screens have traditionally been used to establish genes concerned in a specific organic process of interest. Screens for a extensive variety of phenotypes have been carried out in Arabidopsis, and solely a variety may be mentioned right here. In the activation tagging method, DNA sequences carrying enhancers (e.g. 4 tandemly arranged copies of the CaMV 35S enhancer) are inserted randomly into the genome .