
Just as it’s necessary for the human body to move nutrients to all of the organs, it is vital for green plants to transport sugars to supply its various parts. In humans, this is the circulatory system’s job. But plants do not have a heart-like pump to move these vital energy sources. Instead, plants use a molecular pump. Twenty years ago, the Frommer team identified one of the key components of this molecular pump, which actively loads a sugar called sucrose into the plant’s veins, a tissue called phloem. But how the sucrose produced in the leaves via photosynthesis is delivered to the transporters that move it into the phloem has remained a mystery. Thus, a critical piece of the molecular pump was unknown—the protein that moves the sucrose to the inside of the plant’s leaf cell walls. (via Discovery on how sugars are moved throughout a plant)
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