Sieve-tube Elements
All sieve elements have pores connecting adjacent sieve elements. If these are restricted to specific walls (sieve-plates) that are shared by vertically arranged sieve elements, these are called sieve-tube elements. Sieve-tube elements always have companion cells for life support partners. Sieve-tube elements are only found in flowering plants.
- Link to image of a cross section of Medicago stem showing the detail of the phloem consisting of sieve-tube elements, companion cells, parenchyma cells and fibers.
- Link to image of a cross section of Cucurbita stem showing a sieve-tube element with a companion cell.
- Link to image of a longitudinal section of Cucurbita stem showing sieve-tube elements.