Research: How birch trees adapt to changing climatic conditions to effectively carry out photosynthesis.

Scientists from the Walker lab at Michigan State University and the Plant Research Laboratory (PRL) at the U.S. Department of Energy are studying how paper birch (Betula papyrifera), also known as American white or canoe birch, adapts to changing environmental conditions. They are focusing on photosynthesis - a crucial process for plants.

Berkeley Walker, an assistant professor in the Department of Plant Biology and PRL, likens photosynthesis in plant metabolism to a busy highway. They aim to understand how robust these important pathways are and whether they can handle increased traffic in current and future climate conditions.

Acclimatization - the process of adjusting to new conditions - is an essential part of human life, for example, when winter sets in.

Plants are also forced to adapt to changes in the environment. Scientists are concerned that the increase in atmospheric carbon dioxide (CO₂) concentration and global warming have conflicting effects on photosynthesis and photorespiration. Rising temperatures promote increased photorespiration, while increased CO₂ concentration reduces the efficiency of photorespiration, as shown by other scientific studies.

In a study published in Scientific Reports, scientists investigated how paper birches regulate the activity of photorespiratory enzymes under different environmental conditions. Paper birch was chosen because it inhabits boreal forest biomes, which are among the most northern ecosystems on the planet and are most affected by climate change.

Scientists created growth conditions simulating current, moderate, and extreme climate scenarios for boreal forests, modeled by the Intergovernmental Panel on Climate Change. In each of these scenarios, researchers altered the atmospheric CO₂ concentration and raised air temperature in various combinations.

Luke Gregory, a former graduate student in the Walker lab and the first author of the study, explains that the study aimed to determine whether plants adjust their enzymatic capacity according to needs, or if they maintain some reserve capacity to adapt to unpredictable changes.

Trees were grown from seeds in Professor Daniel Way's lab at the University of Western Ontario. Six different environmental conditions were created using the Biotron facility capable of mimicking almost any climate on Earth.

After four months of growth, Way's lab measured the trees and sent leaf samples to Michigan State University, where Gregory and his team studied the activity of nine enzymes involved in the photorespiratory pathway.

The results showed that trees do not increase their enzymatic capacity depending on the climate in which they grow but maintain the same capacity in all six future climate scenarios. Furthermore, all measured enzymatic capacities were higher than needed for the photorespiratory pathway, indicating that trees are ready to grow even in variable climate conditions.

Gregory noted that it was interesting to discover that plants have a resilience reserve and can maintain a buffer capacity in different conditions. They cope with various changes, whether current, moderate, or extreme conditions.

This is good news: trees have an inherent mechanism that helps them survive in changing climates, at least regarding photorespiration.

However, this is only part of the puzzle in understanding the impact of anthropogenic climate change on photorespiration.

Gregory emphasizes the importance of understanding plants' response to current and future conditions, as they play a key role in human life. Understanding whether plants can adapt or acclimatize to these environments is crucial, as they provide us with fuel, food, and other resources.