Construction of sieve tubes has long been known, but only on the ultrastructure of recent reports allow you to fully understand how these creatures are well adapted to its function, ranging from reducing resistance to the flow of juice floemowego, by withstanding high pressures, up to safeguards against leakage of contents in the event of damage from the attack and pathogens. Floemowy juice contains not only sugars and ions, but also hormones, proteins and nucleic acids. These compounds are involved in signaling, as well as systemic immune reaction against viruses.

Plasmodesmata? cytoplasmic channels łšczšce cells? jednš constitute a feature of the construction odróżniajšcych komórkowš plants from pets. Although plasmodesmata were discovered over a hundred years ago, it was only in the last decade brought closer to an understanding of their role in the regulation of metabolic and signaling between cells of compounds. Of particular interest are the data odnoszšce plasmodesmata function in the regulation of protein transport ponadkomórkowego and nucleic acids.