The average of two leaves was taken to
represent each replicate. Midday measurements of leaf and stem
water potentials were taken during several days in mid-summer.
Diurnal measurements of leaf and stem water potential were taken
on 4 Aug. 1993. Diurnal measurements started at 0700 HR and
ended at 1800 HR. Before each measurement of leaf water potential,
stomatal conductance was measured using a portable photosynthesis
system (LCA2, ADC, U.K.). The same leaves were used for
stomatal conductance and leaf water potential measurements.
Total light interception, for evaluation of canopy coverage, was
measured “on 4 Aug. 1993, when annual shoot and leaf development
was complete. Light intensity reaching the soil surface was
measured with an 80-cm, 80-sensors line PAR Ceptometer (Delta