THO influx, 36Cl– influx and efflux and 22Na influx through maize cortex sleeves were assayed under different temperatures ranging from 5 to 40 °C. The highest Q10 and δH values for THO influx were found between 12 and 32 °C. 36Cl efflux and 22Na influx were almost temperature independent. 36Cl influx was greatly increased above 20°C. These results are consistent with previous conclusions that water flow through maize sleeves is metabolically mediated and that chloride is actively pumped inwards.