The unique feature of plant organisms is the presence of plasmodesmata (PD) between neigh- boring cells. Such plasmodesmatal continuum which exists within the plant body is termed symplasm. Classical view of plasmodesmata as static structures within the cell walls between neighboring cells must be reevaluated. According to our recent knowledge symplast is divided into functional domain. It appeared that symplasmic isolation/communication of cells or group of cells (symplasmic domains or symplasmic fields) is necessary for its proper differentiation within the plant body.