1An area of relatively large pores present in the common end walls of sieve tube elements.
- ‘Between each sieve cell lies a sieve plate with small pores.’
- ‘Sieve elements close to the cambium were identified by aniline blue fluorescence of their sieve plates (open arrowheads) and were positive for serpins.’
A perforated plate in the integument of an invertebrate, especially the madreporite of an echinoderm.
- ‘One of the genital plates serves as the sieve plate, or madreporite, for the water vascular system.’
- ‘In addition it has a sieve plate, or cribribulla, at the expanded base of each exaulos tube, structures not present in these Ordovician sponges.’