The effect of Melatonin pretreatment on growth responses and enhancement of the enzyme's antioxidant system in Chlorella vulgaris under stress of ionizing radiation

Melatonin has important roles in many growth and stress-related responsive processes in plants and algae. In this study, the mediating role of 100 and 500 µM melatonin on photosynthetic pigments and non-enzymatic antioxidant responses of microalga, Chlorella vulgaris to gamma irradiation stress has been studied. The result showed that the alga treated with 100 µM had a stable amount of chlorophyll and a more stability of cell membrane under gamma stress. It was concluded that although melatonin could increase resistance of alga to gamma by strengthen non-enzymatic antioxidant system like more production of proline, however this resistance probably further be related to enzymatic antioxidant system.