Abscisic acid is involved in the response of Arabidopsis mutant sad2-1 to ultraviolet-B radiation by enhancing antioxidant enzymes

In this study, we examined the physiological mechanisms in the responses of Arabidopsis mutant sensitive to ABA and drought 2–1 (sad2-1) to ultraviolet-B radiation (UVB) treatments. The effects of enhanced UVB radiation on plant growth, concentration of UV-absorbing compounds, photosynthesis, endogenous ABA and antioxidant system were investigated in two types of Arabidopsis thaliana — the mutant sad2-1 and the wild type (WT, C24). Results indicated that, under UVB radiation, mutant sad2-1 showed a higher resistance than C24 through accumulating more UV absorption materials, maintaining bio-membrane balance and photosynthesis efficiency, enhancing endogenous ABA content and activating ROS scavenging enzymes. It can be postulated that ABA might participate in a complex signal crosstalk in increasing the tolerance of UVB.