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.

The symplasmic transport of protein and RNAs has emerged as a novel mechanism of cell to cell communication in plant. This movement can occur in selective or a non-selective way between neighbouring cells, tissues or in whole plant. The symplasmic transport is under control both during plant development and in response to environmental conditions. The knowledge about RNAs and proteins that move from cell to cell through plasmodesmata and in the whole plant though phloem is still growing. The transport of mRNA such genes like KN1 or CmNCAP1, has been also described.