中文摘要：

采用开顶箱（OTCs）模拟法和分解袋法,以O3自然浓度（40 nmol·mol^-1）为对照,研究高浓度O3（约120 nmol·mol^-1）对城市自然环境下生长的10年生蒙古栎凋落叶分解和养分释放的影响,分解时长达150 d.结果表明：高浓度O3未对蒙古栎凋落叶的分解产生显著影响.高浓度O3抑制了蒙古栎凋落叶C、K释放,分解150 d,高浓度O3处理K残留率为23.9%,显著高于对照（17.1%）.高浓度O3在分解前期（0～60 d）抑制了凋落叶N、木质素的释放,在分解后期（60～150 d）起促进作用.高浓度O3处理与对照木质素/N变化趋势一致且无显著差异.除分解中期（60 d）外,对照P残留率始终高于高浓度O3处理.C/P变化趋势与P相反,在整个分解过程中,高浓度O3处理C/P高于对照,而且C、N、K残留率以及C/N与凋落叶干质量剩余率呈显著正相关.因此,高浓度O3将对蒙古栎林的营养循环产生一定影响.

英文摘要：

The leaf litters of 10-year-old Quercus mongolica were put in nylon bags and exposed to elevated 03 level （ 120 nmol·mol^-1 ） with the control of 40 nmol·mol^-1 in open top chambers （OTCs） for 150 days to test the effect of high 03 on the litter decomposition. The results showed that no significant difference was observed in residual mass between elevated O3 treatment and the control. Elevated O3 inhibited the release of C and K during the decomposition, the residual rate of K under elevated O3treatment （23.9%） was significantly higher than that of the control （17.1%） after 150-day decomposition. Compared with the control, N mineralization and lignin degradation in elevated O3 treatment were inhibited during early period of decomposition （0-60 d）, but were promoted in later period （90-150 d）. The changes of lignin/N showed no significant difference between elevated 03 treatment and the control during the decomposition. Elevated O3 generally promoted the release of P in leaf litter of Q. mongolica during the decomposition. C/P ratio was higher under elevated O3 than that under control. Significant positive correlation was shown between residual dry mass of leaf litters and the residual rate of C, N, K, C/N ratio during decomposition. Elevated O3 might play an important role in the nutrient cycle of forest ecosystem in high-O3 pollution area.