Abundance in Plant Cells Although they occur in varying numbers, a typical plant cell has between 103 and 105 plasmodesmata, distributed within 1 and 10 per µm2.
Who Discovered Plasmodesmata
Structure
How Are They Formed
Functions of Plasmodesmata
Plasmodesmata are mostly cylindrical-shaped, membrane-lined channels having a diameter of 20 to 40 nm. Their morphology is found to vary significantly during cell growth and differentiation or depending upon the transport requirement of the cell. Composition Plasmodesmata consist of three main layers: the cell membrane, the axial center called the desmotubule, and the region between the desmotubule and the cell membrane called the cytoplasmic sleeve. The cylindrical-shaped desmotubule remains continuous with the outer membrane of the smooth endoplasmic reticulum of each connected cell. At the same time, the cytoplasmic sleeve acts as the principal conduit for cellular passage. The cell membrane portion of the plasmodesmata consists of the phospholipid bilayer. Between the outside face of the desmotubule and the cell membrane’s inner face is an annulus of cytoplasm that appears constricted at each end of plasmodesmata. The presence of actin and myosin protein along the length of plasmodesmata provides flexibility to regulate its aperture.
Connecting symplastic space in plant cells and specialized channels allowing the movement of water, ions, and small signaling molecules such as sugars and amino acids between them.Transporting small proteins such as transcription factors, short interfering RNA, messenger RNA, viroids, and viral genomes.Helping to regulate the function of sieve-tube cells by the companion cells in the phloem through symplastic transport.Linking tissue cells to one another thus helping in tissue growth and development.
