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

Abstract

The effect of the exposure of sunflower (Helianthus annuus L.) seeds to red light laser radiationwith 650 nm 50 mw/cm2by diode laser in germination and growth of seedlings and calli had beenstudied. Seeds were irradiated with red light for different periods of time 5, 10, 15 and 20minutes. The percentage of seeds germination and the average of roots length were differentaccording to exposure time used. Increasing the time of exposure led to the best results in seedgermination percentage (100%), rooting and shooting behavior and flowering accelerationcompared with control. Initiation of calli from explants (roots, stems and leaves) of sunflowerseedlings on Murashige and Skoog media containing 1.0 mg/l of Benzyl adenine and 0.5 mg/l ofNaphthalene acetic acid were succeeded very well from the irradiated seeds. The best irradiationtime was 20 minutes for growth and durability of leaf calli. The fresh weight, protein, DNA, RNAcontents and the specific activity of dihydrofolate reductase of calli of different explants wereincreased with increasing the duration of seeds exposure to red light at 30 and 60 days of growthon media. Results also illustrate increases in protein and oil contents in the irradiated seeds overcontrol seeds, specially at 20 minutes. Using red laser rays for 5 and 20 minutes, resulted in rootsand shoots production from calli of stem and leaf respectively