Ionizing radiation induced changes in phenotype, photosynthetic pigments and free polyamine levels in Vigna radiata (L.) Wilczek

Effects of gamma rays on the free polyamine (PA) levels were studied in Vigna radiata (L.) Wilczek. Seeds exposed to different doses of gamma rays were checked for damage on phenotype, germination frequency and alteration in photosynthetic pigments. Free polyamine levels were estimated from seeds irradiated in dry and water imbibed conditions. Polyamine levels of seedlings grown from irradiated seeds, and irradiated seedlings from unexposed seeds were also measured. Damage caused by gamma irradiation resulted in decrease in final germination percentage and seedling height. Photosynthetic pigments decreased in a dose dependent manner as marker of stress. Polyamines decreased in irradiated dry seeds and in seedlings grown from irradiated seeds. Radiation stress induced increase in free polyamines was seen in irradiated imbibed seeds and irradiated seedlings. Response of polyamines towards gamma rays is dependent on the stage of the life cycle of the plant.

► Gamma irradiation of Vigna radiata (L.) Wilczek seeds and seedlings.
► Decrease in germination frequency.
► Increase in seedling injury with increased dosage of gamma rays.
► Decrease in chlorophyll and carotenoid pigments.
► Change in free polyamine levels.