PARENT SESSION
Organized Oral Session 1: Understanding the impacts of oxidative stress in plants: From molecules to ecosystems
Organizer(s): HS Neufeld and N Grulke
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 510a, Level 5, Palais des congrès de Montréal

Photoprotection: From chloroplast biochemistry to plant form.

Logan, Barry¹, ¹ Biology Department, Brunswick, Maine, USA

ABSTRACT- Plants in nearly all growth environments absorb more light energy than they can utilize to support photosynthetic CO₂ assimilation. This "excess light" is problematic because it can lead to the inactivation of the photosynthetic apparatus, in part via the formation of unstable reactive oxygen species (ROS). The rate of ROS formation can increase during exposure to environmental stresses, since stresses often exacerbate the imbalance between light absorption and photosynthetic light use. Plants minimize photoinactivation via acclimation that influences all levels of organization, from chloroplast biochemistry (i.e. thermal energy dissipation and antioxidation) to plant form (i.e. leaf and branch orientation and arrangement). A broad range of acclimatory responses to environmental stress will be exemplified, with emphasis on chloroplastic antioxidation. Plant responses to stress at larger scales will be considered in terms their effects on the relationship between light absorption and photosynthetic light use.

Key words: Photoprotection, Antioxidants, Photosynthesis, Acclimation