Water (H215O) flow in rice is regulated by the concentration of nutrients as monitored by positron multi-probe system (PMPS)

Using (H2O)-O-15 as a tracer, the effect of the nutrient concentration on the water flow at the discrimination center (DC) of rice was monitored using a positron multi-probe system (PMPS). The maximum velocity of the water flow was achieved by the use of 20x Kasugai's culture solution. The addition of 0.01 to 0.1% NaCl gradually decreased the velocity. In intact plants, the ionic strength of essential elements in the xylem sap may be effective in decreasing the xylem resistance, resulting in the increase of the water flow in the xylem.