Effect of cryptochrome 1 deficiency and spectral composition of light on photosynthetic processes in under high-intensity light exposure.

The role of cryptochrome 1 in photosynthetic processes and pro-/antioxidant balance in the plants was studied. Wild type (WT) and mutant deficient in cryptochrome 1 grown for 20 d under red (RL, 660 nm) and blue (BL, 460 nm) light at an RL:BL = 4:1 ratio were kept for 3 d in different lights: RL:BL = 4:1, RL:BL:GL = 4:1:0.3 (GL - green light, 550 nm), and BL, then were exposed to high irradiance (4 h). Activity of PSII and the rate of photosynthesis in WT and decreased under the high irradiance in all spectral variants but under BL stronger decrease in the activity was found in the mutant than in WT. We assumed that lowered resistance of photosynthetic apparatus in the mutant may be associated with the low activity of the main antioxidant enzymes and reduced content of low-molecular-mass antioxidants in the mutant compared to the WT.