Shade delayed rose flower senescence by influencing antioxidant enzymes activity

The objective of the present investigation was to study the role of shading on antioxidant enzymes activity during the developmental stages of Rosa hybrida. The superoxide anion (O 2 ) production rate and malondialdehyde (MDA) increased from budding stage to senescence stage, while membrane stability index (MSI) decreased. Content of hydrogen peroxide (H 2 O 2 ), activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) increased initially from budding stage to fully open stage and thereafter declined in senescence stage in both sun exposure and shade treatment. Significant decrease was observed in shaded plants in O 2 production rate, H 2 O 2 and MDA content. However, shade significantly increased MSI and the activities of SOD, CAT and APX at all the stages. The results revealed that flowers treated with shade maintained higher level of antioxidant enzymes activity and also showed delayed petal senescence in comparison to sun-exposed flowers.