Pith tissue in plants is found in the center of the stem; what is its primary function?

• A. Found in center of the stem; storage and internal support
• B. Layer surrounding vascular tissue in roots; controls what enters xylem
• C. Rigid, thick cell walls
• D. Wispy, feathery clouds made of ice crystals that form at high levels

Answer: (B)

Pith tissue, located in the center of the stem, is mainly made up of parenchyma cells whose job is to store resources such as nutrients and water. This central storage helps the plant keep reserves and can even contribute to internal support by providing a water-filled, turgid tissue that helps maintain the stem’s structure. The description about a layer around vascular tissue in roots that regulates what enters the xylem refers to the endodermis, a root-specific barrier, not pith. Other choices point to different tissues or phenomena (rigid thick-walled cells describe sclerenchyma, and ice clouds are unrelated). So the primary function of pith is storage with a role in internal tissue support.