Key Points
- Excess light can damage Photosystem II in plants, with slower repair rates observed in colder conditions.
- Plants acclimated to cold for three days showed enhanced photoinhibition repair rates.
- Ecotypes from colder regions demonstrated greater increases in repair capacity.
- Arabidopsis thaliana was studied under controlled temperatures of 22°C, 12°C, and 5°C.
Plants require light to grow, but excessive light can damage their photosynthetic system, specifically Photosystem II. While plants growing in full sunlight have mechanisms to repair this damage, their repair efficiency decreases at colder temperatures. An international research team led by Osaka Metropolitan University has uncovered new insights into how plants adapt to and survive in cold environments.
Associate Professor Riichi Oguchi and researchers from Australia, Austria, and Japan conducted experiments on Arabidopsis thaliana (thale cress), a model organism for plant studies. The team used ecotypes of the plant collected from various regions worldwide.
Initially, all plants were grown at 22°C. Some plants were kept at this temperature as a control group, while others were exposed to 12°C for three days to simulate cold acclimation. Subsequently, both groups were tested at 5°C to examine their photosynthetic responses.
Photoinhibition, the damage caused to the photosynthetic machinery by light, is a natural process in plants that they counteract through repair mechanisms. The study revealed that the control group of Arabidopsis thaliana showed no significant differences in photoinhibition repair rates among the ecotypes at 5°C. However, plants acclimated to colder conditions displayed enhanced repair rates, with ecotypes from colder regions demonstrating the most significant increases.
The findings suggest that plants native to cold climates have evolved to repair photoinhibition damage more effectively after acclimating to lower temperatures. The research was published in the Plant, Cell & Environment journal.
“What we found in this experiment is that plants acclimated in cold temperatures increase their rate of photoinhibition repair in the cold, and the acclimation capacity is higher in the ecotypes from colder regions,” explained Professor Oguchi. He added, “But during the warmer seasons, as suggested by the control group, the plants do not increase the rate as the cost of such repair capacity is high.”
This research sheds light on plants’ complex adaptive mechanisms to challenging climates. Understanding these adaptations could have implications for agriculture, especially in developing crops resilient to cold and high-light conditions.
