Inhibition of Drought Stress Using Folic Acid in Kentucky bluegrass (Poa pratensis L.) under in vitro culture

Considering the high water requirement of grass during growth stages and the limitation of irrigation sources, it is important to find a suitable way to reduce the water requirement of the lawns as cover plants used in the Landscape. The purpose of this study was to investigate the effect of 2,4,5-T on the induction of callus from the hypocotyl explant in Kentucky bluegrass, induce in vitro drought stress using polyethylene glycol and evaluate the tolerance to stress using folic acid in in vitro conditions in Kentucky bluegrass. In the first experiment, the effect of 2,4,5-T in concentrations of 0.5, 1 and 2 mg / L in combination with two concentrations of 0 and 0.1 mg/l BA was investigated and  highest percentage of callus induction at a concentration of 0.5 mg/ of 2,4,5-T alone was observed.  In the second experiment, different concentrations of PEG were used for induction of drought stress in calli. Results showed that increasing the concentration of PEG decreased the growth indices in callus, so that in the concentration of 3 and 4 percent PEG, the least amount of measured traits of callus was observed.  In the third and fourth experiments, folic acid was used to suppress drought stress induced by PEG in two stages of callus and regeneratin plants. The results of the third experiment showed that the use of folic acid in MS medium at 0.5 and 1 mg /l concentration reduced callus growth traits and increased soluble sugar content. In the fourth experiment, the results showed a decrease in the measured traits of regenerated plants in 4% PEG. The highest amount of soluble sugars in regenerated plants was observed in treatment 1 mg / l folic acid in combination with 0 % PEG.