Effect of Sunflower (Helianthus annuus L.) Seeds Treatment by Diode Laser Radiation in Seedlings and Calli Growth


The effect of the exposure of sunflower (Helianthus annuus L.) seeds to red light laser radiation with 650 nm 50 mw/cm2 by diode laser in germination and growth of seedlings and calli had been studied. Seeds were irradiated with red light for different periods of time 5, 10, 15 and 20 minutes. The percentage of seeds germination and the average of roots length were different according to exposure time used. Increasing the time of exposure led to the best results in seed germination percentage (100%), rooting and shooting behavior and flowering acceleration compared with control. Initiation of calli from explants (roots, stems and leaves) of sunflower seedlings on Murashige and Skoog media containing 1.0 mg/l of Benzyl adenine and 0.5 mg/l of Naphthalene acetic acid were succeeded very well from the irradiated seeds. The best irradiation time was 20 minutes for growth and durability of leaf calli. The fresh weight, protein, DNA, RNA contents and the specific activity of dihydrofolate reductase of calli of different explants were increased with increasing the duration of seeds exposure to red light at 30 and 60 days of growth on media. Results also illustrate increases in protein and oil contents in the irradiated seeds over control seeds, specially at 20 minutes. Using red laser rays for 5 and 20 minutes, resulted in roots and shoots production from calli of stem and leaf respectively.