AUTHOR=Schiphorst Christo , Koeman Cas , Caracciolo Ludovico , Staring Koen , Theeuwen Tom P. J. M. , Driever Steven M. , Harbinson Jeremy , Wientjes Emilie 

TITLE=The effects of different daily irradiance profiles on Arabidopsis growth, with special attention to the role of PsbS

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1070218

DOI=10.3389/fpls.2023.1070218

ISSN=1664-462X

ABSTRACT=In nature light is never constant, while in the controlled environments used for vertical farming, in vitro propagation, or plant production for scientific research, the light intensity is often kept constant during the photoperiod. To investigate the effect on plant growth of a varying irradiance during the photoperiod we grew Arabidopsis thaliana under three irradiance profiles: a square-wave profile, parabolic profile with a gradually increasing and then and decreasing irradiance, and a regime comprised of rapid fluctuations in irradiance. The daily integral of irradiance was the same for the three treatments. The leaf area, and plant growth rate and biomass at time of harvest were compared. The plants grown under the parabolic profile had the highest grow rate and biomass. This we could explain by a higher average light-use efficiency for carbon dioxide fixation. Furthermore, we compared the growth of wild type plants with those of the PsbS deficient mutant npq4. PsbS  triggers the fast non-photochemical quenching process (qE) that protects PSII from photodamage during  sudden increases in irradiance. Based mainly on field and greenhouse experiments the current consensus is that the npq4 mutants grows slower in fluctuating light. However, our data shows that this is not the case for several fluctuating light conditions under otherwise identical controlled climate room conditions.