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WATER RELATIONS AND DROUGHT TOLERANCE IN 2 WHEAT-VARIETIES UNDER
WATER-STRESS
KHAN AH; ASHRAF MY; ASLAM RM
Abstract:
A drought resistant variety of wheat (Pak-15800) was compared with a
susceptible variety (Sarsabz) under water stress and the relationship
between leaf water, osmotic, turgor potentials and relative water
contents (RWC) were studied. The water stressed plants had lower leaf
water potential than control and at a given RWC Pak-15800 had lower
water potential than Sarsabz which partly accounts for its better
drought resistance. In both the varieties pre-stressed plants maintained
osmotic potentials lower than control. In Pak-15800 osmotic potential
was significantly lower (-0.06 to -0.11) than Sarsabz. Both control and
pre-stressed Pak-15800 plants had higher turgor (0.1 to 0.15 MPa) than
Sarsabz at RWC between 65 and 80%. Both pre-stressed and control
Pak-15800 had greater elasticity (a lower elastic modulus) than Sarsabz.
An understanding of the differences between osmotic and turgor
potentials between varieties could be used as a tool in breeding program
for wheat.
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