It is possible, however, that
plant IBPs could exhibit ice nucleation inhibition activity. If so,
this could be of value in situations where inhibition of intrinsic
ice nucleators is critically important. Most plant IBPs appear to be
present in the apoplast, where ice forms in freeze tolerant plants,
and consequently these IBPs apparently do not inhibit ice nucleation. Wisniewski et al. (1999), however, reported a dehydrin with
thermal hysteresis activity, in the cytoplasm of acclimated peach
bark and xylem cells, including xylem ray parenchyma cells, which
are known for their ability to supercool to very low temperatures.