Plants, much like humans, can suffer from the adverse effects of excessive sunlight. In a pioneering study conducted by Pierrick Bru, a Ph.D. student collaborating with Alizée Malnoë at Umeå Plant Science Centre and Umeå University, a unique component of plants’ internal sun protection mechanism, known as qH, has been explored for its remarkable adaptability.
The marvel of photosynthetic organisms lies in their ability to convert sunlight into energy. Similar to miniature solar panels, plants possess tiny structures within their cells that capture sunlight and transform it into energy-rich compounds vital for growth and overall health.
However, when exposed to excessive light, these structures can become overloaded and damaged. To mitigate this, plants employ a mechanism that converts surplus sunlight into heat, allowing it to dissipate harmlessly.
Pierrick Bru’s research focused on qH, a component of this protective mechanism that operates at a deliberate pace. “This component does not work quickly. It takes hours to turn on and off, and it is mainly active when plants are under prolonged excess of light stress, especially when combined with other environmental clues such as cold and/or drought,” explains Bru.
Using the model organism Arabidopsis thaliana, the research team conducted experiments by modifying the plant, removing one or more of the mini solar panels. Surprisingly, the plant exhibited a backup system: if one panel was missing, others could compensate for it. However, the absence of a specific small panel, Lhcb6, hindered the proper functioning of qH, resulting in less excess sunlight being converted into heat.
The study also delved into the factors influencing the qH mechanism. Two of these factors were identified as critical in building or repairing photosystem II, one of the functional units where photosynthesis occurs. Dysfunction in either of these factors disrupted the normal functioning of photosystem II, consequently impacting the plant’s ability to utilize the qH sun protection mechanism.
Moving forward, Pierrick Bru and his colleagues plan to further investigate the intricacies of how defects in photosystem II impact the qH protection mechanism. This knowledge holds the potential to shed light on whether photoprotection qH is regulated similarly in crops.
With climate change leading to more extreme weather conditions affecting crops, understanding how qH operates and how plants cope with environmental stress becomes crucial. Bru emphasizes, “Understanding how qH works and how plants cope with environmental stress will help to find ways to improve plant resistance to excess sunlight, improving plant growth and increasing agriculture productivity.” This research represents a significant stride towards unraveling the mysteries of plant adaptability in the face of changing environmental conditions.