Lipid peroxidation, antioxidant enzyme activity and osmotic adjustment changes in husk leaves of maize in black soils region of Northeast China

Abstract

Two varieties of maize (Zea mays L.) grown in fields in Black soils of Northeast China were tested to study the variation of membrane lipid peroxidation, osmotic adjustment, and antioxidant enzyme activity in husk leaves of maize by the methods of UV spectrophotometry. The results showed that MDA content and membrane relative permeability increased continuously along with the growth of maize, and antioxidant enzyme activity in husk leaves of maize increased first and then decreased with the growing of maize, and reached peak value at grain filling period. It indicated that the decrease of antioxidant enzyme activity was closely correlated to the accumulation of MDA. Patterns of soluble sugar and proline were consistent with antioxidant enzyme activity, showing that osmotic adjustment could protect many enzymes important forcell metabolism through accumulation of soluble sugar and proline. Proline content of husk leaves was more variable than soluble sugar, which showed that proline was the predominant osmotic adjustment substance in husk leaves of maize. Key words: Maize, husk leaves, antioxidant enzyme, membrane lipid peroxidation, total soluble sugar, proline.