Yes, xylem cells do have a plasma membrane, although the prominence and function of the plasma membrane changes as the cell matures.
While mature xylem vessel cells, which are a major component of xylem tissue, undergo programmed cell death and lose their cytoplasmic contents, including the plasma membrane in some areas, the presence of active ROP11 Rho GTPases highlights the existence and functional importance of specific plasma membrane domains in these cells during their development. Specifically, these GTPases form oval plasma membrane domains that influence secondary cell wall formation by disrupting cortical microtubules, directing the formation of pits. This indicates that at least during development and maturation, xylem cells possess a functional plasma membrane.
Furthermore, the persistence of some membrane components is vital for the structural integrity and functionality of the xylem. The reference specifically mentions "oval plasma membrane domains," suggesting the presence of a plasma membrane, even if it's not uniformly distributed throughout the cell's lifespan.
In summary, while mature xylem cells might lose significant portions of their plasma membrane as part of their differentiation process, they do possess a plasma membrane during their development and maturation, which plays a crucial role in cell wall formation.
