A pith ray refers to the specialized tissue found in the stems of woody plants, particularly in dicotyledonous plants. It is a radial arrangement of living cells that are mainly responsible for the lateral conduction of water, nutrients, and sugars within the stem. The pith ray, also known as medullary ray, extends from the center of the stem towards its outer periphery, forming a network of radial strips.
Composed of cells that are relatively larger than those of the surrounding tissues, the pith ray primarily functions to transport materials horizontally across the stem. It connects the medullary or pith regions of the stem with the cambium and phloem regions, facilitating the exchange of substances among these tissues. Moreover, it assists in storage, particularly by storing starch, fats, oils, and resin.
Additionally, the pith ray contributes to the overall structural integrity of the stem by providing radial support. By connecting the central pith region with the outer tissues, it helps distribute mechanical stresses and supports the plant, enabling it to withstand external pressures and maintain its shape.
The pith ray plays a vital role in plant growth, development, and functioning. Its complex network ensures effective conduction of water, nutrients, and sugars, prevents mechanical failure, and aids in storage. Through its multiple functions, the pith ray supports the overall survival and success of woody plants.
