Different impact of high light on the response and recovery of wild type and lut2 mutant of Arabidopsis thaliana at low temperature

Carotenoid composition is important for plant protection against unfavorable environment. In the present study the effect of several days treatment with high light illumination at low temperature (500 mu mol photons m(-2) s(-1) and (12/10 degrees C) on Arabidopsis thaliana plants-wt and mutant lut2, was investigated. In addition, a comparative study of the ability of wt and lut2 plants to recover after one week return to control conditions was performed. The response of wt and lut2 to both stress factors was evaluated by changes in net photosynthesis, photochemistry and energy distribution and interaction between both photosystems. The alterations in oxygen evolving capacity were evaluated by registration of flash-induced oxygen yields and kinetics of initial oxygen burst. For the first time the effect of exposure at low temperature/high light on the fluidity of thylakoid membranes isolated from wt and lut2 mutant was followed. The analysis of low temperature (77 K) fluorescence emission and excitation spectra revealed that during exposition to both stress factors the antenna size of photosystem I and photosystem II were affected. Lut2 mutant showed higher sensitivity to the inhibitory action of high light at low temperature, with the grana-situated photosystem II centers being more affected. However, lut2 mutant exhibited a higher ability to restore the photosynthetic activity after recovery period under control conditions. Data presented showed that at low temperature, complete replacement of lutein in lut2 mutant by xanthophyll cycle-associated carotenoids did not result in higher protection against high light, but facilitated better recovery during the recovery period.

Automated summary

The study investigated the effect of high light at low temperature on Arabidopsis thaliana plants, with the mutant lut2 showing greater sensitivity but higher ability to restore photosynthetic activity during the recovery period. The analysis revealed changes in photosystems I and II antenna size and highlighted the importance of carotenoid composition in plant protection against high light exposure.