CELL TYPE CYTOPLASMIC FEATURES CELL WALL FEATURES 3-D GEOMETRY
Sieve Cells

Closely associated with parenchyma cells called Albuminous Cells

No nucleus at maturity
No chloroplasts
No mitochondria
Cytoplasm consists of P2 protein fibrils (slime) and
Convoluted and vesiculated Endoplasmic Reticulum in a parietal position (around the circumference of the cell)
 
Thickened primary cell wall with regions of numerous primary pit fields associated with callose.
 
Transverse Isodiametric
Longitudinal  Elongated cylinder with oblique or tapering end walls.
Longest axis is in vertical direction.