Biological Effects of Semiconductor Laser Irradiation on Seedling Vigor and Biochemical Attributes in Sunflower

Sunflower is an important economic plant which has been extensively studied in agricultural research.In this work, sunflower seeds were irradiated with semiconductor laser with an irradiation intensity of 12 mW/cm 2 .The nucleic acid, protein, vitamin B1, C and E contents in the sunflower seeds were analyzed after irradiation for different times (0, 50, 100, 150, 200, 250, and 300 s).The germinability, germination percentage and vigor index of the seeds were measured.Besides, the chlorophyll, nucleic acid and proteins contents in the sunflower seedlings were also determined.The results showed that with the increase of irradiation time, the nucleic acid, protein, and vitamin B1 contents in the seeds and seedlings exhibited an increasing trend first and then decreased.The germination percentage, germinability and other physico-chemical properties were maximal after irradiation for 150-200 s.The semiconductor laser irradiation intensity at 12 mW/cm 2 for 150 s can effectively affect the seeds and seedlings nucleic acid, protein and vitamin contents.