ABSTRACT: Reactive oxygen species (ROS), such as O2·¯, are formed by electron transfer to a molecule with stable electron configuration, in electron transport chains in the cell. ROS are very reactive molecules which are formed at higher rates under stress, such as drought, high insolation, heath, inadequate mineral nutrition, and such conditions lead to impairment of various physiological and biochemical processes in the cell. To reduce production of ROS, and their detrimental effect, plants developed various enzymatic and non-enzymatic protective mechanisms. Superoxide dismutase (SOD) is one of the most important antioxydative enzymes, which removes superoxid anion radical (O2·¯), whose rate of production is the highest under unfavorable environmental conditions. Plant tissues that exhibit delayed senescence often have higher cytokinin content, which is accompanied by reduced amount of ROS. The focus of this paper is to examine whether foliar application of cytokinins to young wheat plants insufficiently supplied with nitrogen affects the activity of SOD and amount of O2·¯. Application of trans-zeatine (CK) reduced the activity of SOD, but this reduction was not accompanied by an increase in the amount of O2·¯. Application of benzyl adenine (BA) also reduced the activity of SOD, with concomitant increase in the amount of O2·¯ in wheat leaves.
Zbornik Matice Srpske za Prirodne Nauke. 01/2008;