apoplast

apoplast

1. a PLASTID which lacks CHROMATOPHORES. The adjective apoplastic is applied to individual protozoans that lack colour in a group which is generally coloured. Apoplasty occurs when cell division is so fast as to outpace plastid division, producing individuals which are formed without plastids.
2. those areas of the plant that are outside the SYMPLAST, comprising the parts outside the PLASMALEMMA, such as cell walls, intercellular spaces and the dead tissues of XYLEM.