Tubules connecting two cisternae of endoplasmic reticulum located at two opposite ends of a plasmodesmata are called as

Key Points

• Plant cells have cell walls around their plasma membranes for rigidity and support.
• Plant cell walls have plasmodesmata through which intercellular connections are maintained.
• Plasmodesmata are cell junctions in plants which form fine cytoplasmic channels between cells.
• These channels are about 20-40 nm in diameter.
• Desmotubule is a narrow cylindrical structure that runs through the centre of the plasmodesmata.
• Desmotubules are continuous with the endoplasmic reticula of adjoining cells.
• There is a cytosolic annulus between the inner wall of plasmodesmata and desmotubule through which molecules can pass.

Additional Information

• These plasmodesmata connections allow free movement of small metabolites and growth hormones between plant cells.
• They help in intercellular transport of RNA and proteins.
• They have a dynamic structure to selectively allow transport of some macromolecules.
• These are very important in the movement of proteins from companion cells to sieve elements of the phloem.
• The symplast pathway involves movement of molecules through the plasmodesmata.
• The symplast pathway is vital for the cells with casparian strips.