Abstract
This work examined the long-term effects of periodic high light stress on photosynthesis, morphology, and productivity of low-light-acclimated Arabidopsis plants. Significant photoinhibition of Arabidopsis seedlings grown under low light (100 μmol photons m-2 s-1) was observed at the beginning of the high light treatment (three times a day for 30 min at 1800 μmol photons m-2 s-1). However, after 2 weeks of treatment, similar photosynthesis yields (Fv/Fm) to those of control plants were attained. The daily levels of photochemical quenching measured in the dark (qPd) indicated that the plants recovered from photoinhibition within several hours once transferred back to low light conditions, with complete recovery being achieved overnight. Acclimation to high light stress resulted in the modification of the number, structure, and position of chloroplasts, and an increase in the average chlorophyll a/b ratio. During ontogenesis, high-light-exposed plants had lower total leaf areas but higher above-ground biomass. This was attributed to the consumption of starch for stem and seed production. Moreover, periodic high light exposure brought forward the reproductive phase and resulted in higher seed yields compared with control plants grown under low light. The responses to periodic high light exposure of mature Arabidopsis plants were similar to those of seedlings but had higher light tolerance.
Highlights
When light levels exceed the capacity of photosynthesis in leaves, the excess absorbed energy can lead to the inactivation of the reaction centers (RCs)
During a 108 s period, the qPd of HL-Seedling and HL-Rosette plants increased by 3.4 % and 1.4%, respectively. These results show that A. thaliana was able to repair from photoinhibition after the high light treatment, with full recovery reached after the 14 h night/dark period
Arabidopsis plants were able to overcome the stress of high light and recovered once being moved to the dark or low light irradiance
Summary
When light levels exceed the capacity of photosynthesis in leaves, the excess absorbed energy can lead to the inactivation of the reaction centers (RCs). This can lead to the formation of reactive oxygen species (ROS) and eventually to the reduction of electron transport efficiency and photosynthesis as a whole—the phenomenon known as photoinhibition (Powles, 1984; Osmond and Förster, 2008; Adams et al, 2013). High light stress influences the photosynthetic process and continuously influences starch synthesis and reproductive growth. Seedlings of Eucalyptus pauciflora and Eucalyptus nitens experiencing a high degree of photoinhibition grew better (producing higher biomass and more extensive root growth) than seedlings that displayed less or no photoinhibition (Blennow et al, 1998; Close and Beadle, 2003)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
