Abstract: An open-top chamber experiment was conducted to examine the effects o f elevated atmospheric O3 (80±8 nmol·mol-1) on the total phenols, flav onoid, condensed tannin, and MDA contents, and the total antioxidative capacity of Quercus mongolica leaves. Elevated O3 increased the contents of tota l phenols and condensed tannin by 4817% and 2677% (P<005), and the fla vonoid and MDA contents by 2466% and 526% (P>005), respectively. The t otal antioxidant capacity of Q. mogonlica leaves determined by DPPH method w as enhanced significantly (P<005), and had an obvious linear relationship with the contents of total phenols and condensed tannin.

Key words: poplar plantation, furrow irrigation, productivity, drip irrigation, soil moisture sensor, soil moisture content