Concentrations of total S in the oldest, middle,
and youngest leaves of plants grown in the absence of S and at high (7
mm) NO3− compared with the
predicted values for each leaf type. Predictions were based on the
growth rate, assuming that no S was transported into or out of each
plant part, and therefore predicted values represent a dilution curve
attributable to growth. Closed circles, Measured values; dashed lines,
predicted values. DW, Dry weight.