Rp. Beckett et al., THE EFFECT OF FLUCTUATING SUBSTRATE SALINITY ON THE YIELD AND FLAG LEAF PHOTOSYNTHESIS OF WHEAT, South African journal of botany, 61(1), 1995, pp. 35-38
The effects of constant and fluctuating substrate salinity on flag lea
f photosynthesis and grain yield of wheat were investigated. Plants ex
posed to salinity fluctuating around a mean integrated value of 25 mol
m-3 NaCl (0-50 mol m-3) and around 50 mol m-3 NaCl (25-75 mol m-3) ha
d yields 36 and 38% higher, respectively, than those receiving the cor
responding constant salinity. Plants treated with salinity fluctuating
from 50 to 100 mol m-3 NaCl had a 14% lower yield than those receivin
g 75 mol m-3 NaCl. Flag leaf photosynthesis did not vary between treat
ments and during salinity fluctuations, suggesting that differences in
flag leaf longevity caused the observed differences in yeild. Results
suggest plants grown under constant salinity are unlikely to behave i
n the same way as those in field situations, where fluctuation rather
than constant salinity occurs.