Effect of blue and white lights on physiological characteristics of two wheat cultivars under salinity stress

Light is an energy source for photosynthetic organs and the type of optical wavelength plays an important role in growth. The effect of blue light investigated on delta-1-pyrroline-5-carboxylate (proline precursor) in 2-wheat cultivar, BAM (resistant to salinity) and Tajan (sensitive to salinity) in a culture medium. There were 5 salinity treatments including 0 (control), 50, 100, 150, and 200 mM NaCl. In addition, there were two light treatments, namely exposure to blue and white light. After five days of growth of wheat seedlings, the growth indices (fresh weight, dry weight, and longitudinal growth), proline, chlorophyll a and b, sodium, and potassium contents, peroxidase enzyme activity, malondialdehyde, and pyrolin-5- Carboxylate (proline precursor) contents were measured. Data were analyzed using Duncan statistical test. Blue light increased the amount of proline and PSC in the salinity-resistant cultivar. In the sensitive cultivar, the amount of potassium under the white light was higher than that under the blue light in different levels of salinity. The amount of sodium accumulated under the influence of blue light in different concentrations of salt in the resistant cultivar was higher than that in the sensitive cultivar. Peroxidation activity of the resistant wheat cultivar was higher and blue light did not increase this attribute, but the amount of malondialdehyde in the sensitive cultivar increased under the blue light regime and with increasing level of salinity. Fresh and dry weight of plants in the resistant cultivar was the highest under the white light. In addition, plant length in the resistant cultivar under increasing concentration of salt was more than that in the sensitive cultivar under both light regimes.