Sieve Tube Elements

Sieve tube elements and sieve plates are two completely different elements in a plant, despite the similar names. Sieve tube elements are components that form end to end to create sieve tubes, while sieve plates form between the sieve tubes. The sieve plate has micropores in it that connect the adjacent sieve tubes, allowing for material exchange between each tube. Normally this would pose a risk to the plant because one damaged sieve tube would cause the whole plant to “bleed out” as all of the water and nutrients it was transporting would be lost. To combat this, the plant can detect when the sieve tube is damaged and secrete callose, which can seal the pores in the sieve plate to stop nutrient and water transfer in that tube. This process acts much like coagulation in the human body.