Studies on Metabolism of Active Oxygen Spec ies in the Leaves of YoungVirus-free Trees of Ziziphus jujuba‘Junzao’ Effects of elevated CO2 and O3 concentration and combined on ROS metabolism and anti-oxidative enzymes activities of maize(Zea mays L.) The role of reactive oxygen species metabolism in resistance mechanism to gray leaf spot in maize Effects of combined elevated temperature and drought stress on anti-oxidative enzyme activities and reactive oxygen species metabolism of Broussonetia papyrifera seedlings Studies on Metabolism of Active Oxygen Spec ies in the Leaves of YoungVirus-free Trees of Ziziphus jujuba‘Junzao’