Study links trees’ sense of shape to wood that straightens stems
Experiments with young poplars found that specialized wood changed where it formed when researchers disrupted directional cues from gravity and light.
Young poplar trees corrected curved stems by changing where they produced wood capable of exerting a pulling force, researchers found. The experiment indicates that trees’ internal awareness of their shape helps control the growth responsible for adjusting their posture.
The team first placed the trees horizontally. As they grew, specialized tissue known as tension wood developed on the stems’ upper side, pulling them upward. After approximately ten days, the researchers transferred the curved trees to an apparatus designed to separate their internal shape-sensing response from environmental cues.
Inside the apparatus, a platform rotated within a sphere lit evenly from all directions. Rotation prevented a stable directional signal from gravity, while uniform illumination removed light as a directional guide. Over the following weeks, the stems became nearly straight.
Examination of the newly developed wood showed that tension wood production had stopped on the original side and begun on the opposite side. The researchers said this new growth appeared to pull against the earlier curvature, rather than simply continuing to bend the stems upward.
The findings suggest tension wood has a broader role in posture control than previously understood. Bruno Moulia, INRAE research director, said poorly coordinated formation of this wood can create excessive internal stresses that may affect wood quality.
