How do plants transport glucose from photosynthesizing tissues to other parts of the plant?

Plants do not typically transport glucose directly from photosynthesizing tissues to other parts of the plant. Instead, the glucose produced during photosynthesis is primarily converted into sucrose, a 12-carbon sugar, for translocation.1

This transport occurs through a specialized vascular tissue called the phloem. The movement of these sugars from source regions (such as mature leaves) to sink regions (such as growing fruits, flowers, roots, or tubers) is driven by metabolic processes. While the exact mechanism is still studied, the most widely accepted explanation is the pressure-flow hypothesis. This theory suggests that the active loading of sugars into the phloem at source regions increases the osmotic pressure, while the removal of sugars at sink regions lowers it, thereby establishing a pressure gradient that facilitates the flow of the solution through the sieve tubes.23