Diode Laser Radiation Effects in Initiation and Growth of Sun Flower Plant (Helianthus annuus L.) Callus

Abstract

The research involved the studying of the effect of the red laser radiation at wave length 650 nm and power 50 mw/cm2 using a semi-connector laser (diode laser) for different periods of times 5,10,15,20 min. in the initiation and growth of callus sunflower (Helianthus annuus L.). Exposing of sunflower root, stem and leaf explants to laser radiation leads to clear increase in rate of growth indicators of calli (fresh weight of calli, dihydrofolate reductase activity and the amount of protein, DNA, RNA. folate) especially after 6o days of exposure. It was found that 20 min. duration was ideal to produce maximal activity of dihydrofolate enzyme giving value of 53.411µgm/min./mg protein and an increase in the amount of protein. DNA, RNA and folate to achieve 4.3 mg/gm, 23.311, 221,888, 1.2µgm fresh weight respectively after 60 days of leaf calli growth. These changes in growth indicators reflect on differentiation of stem calli to a group of white roots with dense root hairs after 35 days of stem explants exposure to 10 min. While leaf calli stimulated to form a number of vegetative branches after 50 days of exposure to 20 min. All shoots were rooted easily in hormone free medium. Plants continued to grow to form sunflower disks after 50 days of rooting process and growth. .