Abstract
Responses of the wheat commercial cultivar ‘Faisalabad-2008’ to various concentrations of 2,4-D and the effect of water
stress on callus induction and regeneration efficiency were evaluated. For the assessment of responses to water stress,
growing morphogenic calli of 7, 14 and 21 days after culture were exposed to different concentrations of water stress. For
induction of stress wheat calli were exposed to different concentrations of PEG 6000 (0, 4, 8, 12 and 16% (w/v) and mannitol
(0, 0.5, 1, 1.5 and 2% (w/v). The effect of these stresses on shoot and root length, relative water content and electrolyte
leakage were also determined. The results indicated that maximum regeneration was observed at 5mg/L of 2,4-D, increase or
decrease in 2,4-D concentration resulted a decrease in regeneration efficiency. Maximum regeneration was observed from 21
days old calli. Significant decreases in the number of shoots regenerated per calli; shoot and root length and relative water
contents occurred under both stresses with the highest reduction under mannitol-induced osmotic stress. Electrolyte leakage
increased at higher PEG and mannitol concentrations. Furthermore, both PEG and mannitol induced drought stress
efficiently but mannitol was more severe. The results here will be helpful for improvement of the wheat crop tolerance
against water stress.
