Photooxidation in interveinal tissues of magnesium-deficient leaves is associated with sugar accumulation.

Magnesium deficiency causes higher sugar accumulation in interveinal tissues of rapeseed leaves, intensifying photooxidative stress and chlorosis.

• Why it matters: Understanding tissue-specific responses to Mg deficiency is crucial because it reveals why interveinal areas are more severely affected, which can inform strategies to mitigate leaf damage.
• What they did: Researchers used a hydroponic system to analyze Mg deficiency effects on rapeseed leaves, measuring ROS, photosynthesis, sugar levels, and gene expression in different leaf tissues, with 2 experiments involving foliar fructose application.
• The result: Interveinal tissues accumulated significantly more soluble sugars despite similar Mg levels, and sugar application worsened chlorosis, indicating carbohydrate buildup impairs vascular function and promotes photooxidative damage.