Some features of stelar tissues isolated from corn roots

In relation to radial ion transport to xylem vessels in higher plant roots, some features of stele, cortex, and root tip freshly isolated from 2-day-old corn roots grown under moistened or submerged condition were investigated. The contents of P, K, and Mg in primary roots decreased gradually from the apical to the basa1 region axially. The stele contained P, Na, Cu, Fe, and Mn in higher level than the cortex. The O₂ uptake rate of root tip was much higher and that of freshly isolated stele was as high as that of fresh cortex. In stele, more CN sensitive respiration was observed than in cortex. Although isolated stele absorbed tess ³²p than cortex and root tip, the incorporation of ³²p into organic compounds in stele was as much as in root tip. These results show that the freshly isolated stele has high metabolic activity and must play an inherent role in radial and selective ion transport in situ.