Abstract: 【Objective】 To study the effects of long-term warming on the photosynthetic daily dynamics of three main plants in Stipa breviflora desert steppe—Stipa breviflora,Artemisia frigida and Kochia prostrata,and to explore the response of desert steppe plants to warming.【Methods】 The experiment was conducted in a random split plot design with two treatments：warming and non-warming（control）. A far-infrared radiator was used to simulate the warming treatment,and a portable photosynthetic instrument was used to monitor the daily dynamics of photosynthetic characteristics of Stipa breviflora,Artemisia frigida and Kochia prostrata.【Results】 Long-term warming made the daily dynamic curve of photosynthetic characteristics of Stipa breviflora and Kochia prostrata slightly changed,and Artemisia frigida were more affected by warming. There was a certain difference in the response trend of the daily dynamic average of photosynthetic characteristics to warming. Among them,Stipa breviflora had the highest response degree,and Kochia prostrata and Artemisia frigida had a lower response degree. The photosynthetic rate and transpiration rate of Stipa breviflora,Artemisia frigida and Kochia prostrata were increased to varying degree by increasing temperature,but water utilization rate was reduced.【Conclusion】 Long-term warming had little effect on the photosynthetic characteristics of the three main plants Stipa breviflora,Artemisia frigida and Kochia prostrata in Stipa breviflora desert steppe. Different plants had different responses to warming. Warming had a relatively large effect on the photosynthetic characteristics of Stipa breviflora. The daily dynamic curve of photosynthetic characteristics of Artemisia frigida had a relatively obvious response to warming.

Key words: Long-term warming, Stipa breviflora desert steppe, Daily dynamics of photosynthesis, Stipa breviflora, Artemisia frigida, Kochia prostrata