Abstract: Temperature is an important environmental factor affecting stem anatomical structure. It is less well understood how it affects the structure of wetland plants. In this study, we used opentop growth chambers (OTCs) to simulate climate warming, based on the prediction of future atmospheric warming by IPCC, to study the response of stem anatomical structure of the lakeside dominant species Hippuris vulgaris to the simulated warming in a typical plateau wetland in Northwestern Yunnan (Napahai basin). The results showed that warming significantly increased epidermal cell thickness and cuticle thickness of aboveground stem. The size of parenchyma cells and epidermal cells of the aboveground stem showed increasing trends. All the aboveground stem traits showed increasing trends with increasing temperature. Warming had a significant effect on cuticle thickness of belowground stem. All the belowground stem traits showed trends of decreasing first and then increasing with the increasing temperature. Among temperature variables, the annual mean temperature and daily mean temperature were the most significant factors positively affecting aboveground stem anatomical structure of H. vulgaris. The maximum temperature and annual mean temperature had most significantly negative impacts on the belowground stem anatomical structure of H. vulgaris. Our results suggest that warming significantly affects stem anatomical structure of H. vulgaris, reflecting its effective adaptation to warming, and thus reveal the response patterns and ecophysiological adaptive strategies of plant structure in plateau wetland to climate warming.

Key words: super rice, ozone, photosynthesis, dry matter production, planting density.