Desiccation-induced changes in viability, lipid peroxidation and antioxidant enzyme activity in Mimusops elengi seeds
Intermediate seeds of Mimusopsis elengi showed obvious membrane lipid peroxidation during desiccation. When the moisture content (MC) decreased from initial 41.8 to 6.1%, seed viability significantly decreased from 100 to 23%, consorted with activity changes of a few anti-oxidative enzymes. The activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) gradually showed a similar change rend in the process of desiccation, namely their activities firstly increase to the maxima, and then decreased. The exception was catalase (CAT) which showed a general decrease in activity during the whole experimental period. It indicated that seed deterioration of M. elengi was related with uncontrolled production of reactive oxygen species (ROS) and the ability of enzymes mentioned to eliminate such toxic products during drying seeds. Thus, the fact that oxidative stress induced unmendable damage was considered as one of the critical factors which resulted in viability loss of M. elengi seeds.
Keywords: Intermediate seeds, desiccation, reactive oxygen species, antioxidant enzymes, lipid peroxidation, Mimusops elengi