Abstract: An open-top chambers (OTCs) experiment was carried on the combined effects of ozone and drought on leaf stomata of Acer truncatum Bunge. Four treatments were designed: control (ambient air without drought stress), drought (ambient air with 40-50% of soil waterholding capacity), enhanced ozone (ambient air with additional 118 μg·m^-3 ozone without drought stress), and enhanced ozone and drought (ambient air with additional 118 μg·m^-3 ozone and 40-50% of soil waterholding capacity). 41 days after treatment, the stomatal density did not change significantly under ozone exposure, but increased significantly under drought stress and combined stress (P<0.05). 41 and 62 days after treatment with ozone and drought stresses, there were no significant differences in stomatal area, length and width among treatments (P>0.05), while 110 days after treatment with ozone and drought, the stomatal area, length and width were smaller than those of the control (P<0.05). Compared with the control, stomatal index increased significantly 110 days after treatment by ozone and drought (P<0.05). The stomatal opening degree reduced significantly when A. truncatum was exposed to enhanced ozone and drought (P<0.05). These results suggested that accumulating effects were reflected on stomatal characteristics of A. truncatum under ozone stresses. Ozone and drought stresses influenced the stomatal characteristics interactively. The synergistic effect of ozone and drought stresses was evidenced on the stomatal aperture. It was suggested that drought could protect plants against ozone-induced damage by causing the closure of stomata and preventing the entry of ozone into the leaves.

Key words: Phyllostachys edulis, extensive management, cultivation history, diversity, available K, available P., soil bacterial and fungal communities, DGGE