How is medullary ray formed ?

Dear student.

Two system of parenchyma exist in secondary xylem, derived from meristematic cells called as ray initials and fusiform initials. The ray parenchyma is the more extensive. It forms radial sheets of tissue called medullary rays which maintain a living link through the wood between pith and cortex. Its functions include food storage, deposition of tannins, crystals and so on, radial transport of food and water, and gaseous exchange through the intercellular spaces.


Regards.