Plasma membrane depolarization precedes photosynthesis damage and long-term leaf bleaching in (E)-chalcone-treated Arabidopsis shoots

The plant phenolic compound (E)-chalcone has been previously found to induce apoptosis-like programmed cell death in roots, and noticeable seedling size reduction and progressive de-greening (bleaching) in shoots of Arabidopsis thaliana seedlings. In this work, we demonstrate that this progressive de-greening occurring on Arabidopsis shoots after (E)-chalcone treatment, is directly linked to early plasma membrane depolarization and dramatic effects on chloroplasts structure and function. Later effects in chalcone-treated seedlings included ROS accumulation, pigment degradation, reduced photosynthetic activity, bleaching, and eventually cell death. De-greening and pigment degradation induced by (E)-chalcone were partially reversed when NaCl was added together with chalcone, which could be related with restoration of altered pH gradients.