Positive charges from spermine protect the photosynthetic system in plant cells when exposed to too much light. Researchers studied the effects of spermine, putrescine, and methylamine on isolated plant membranes. Spermine, with its four positive charges, was the most effective at improving photosynthetic performance under stressful light conditions. This protection is likely due to spermine's ability to interact with proteins in the photosynthetic system.