Abstract: Based on daily temperature data (1951-2017) from meteorological stations of Changchun, Harbin, Baicheng, Qiqihar, Hailun and Nenjiang in Songnen Plain, we calculated the accumulated temperature above 10 ℃ in each region and constructed the annual activity accumulated temperature sequence of each meteorological station. We analyzed the variation characteristics of active accumulated temperature in different regions of Songnen Plain and constructed predicting model of the active accumulated temperature in the next decade using the autoregressive integrated moving average model (ARIMA model). Meanwhile, using the production data of soybean, maize and rice in Heihe, Suihu, Harbin, Siping and Shenyang provided by the website of the National Bureau of Statistics of China, we established regression relationship between activity accumulated temperature and crop yield. The results showed that the active accumulated temperature in the six meteorological stations had significant variation over the past 67 years, and the periods of 1981-2010 were the main years for the increase in accumulated temperature. Since 1993, the active accumulated temperature increased obviously, and the average activity accumulated temperature in 2001-2017 increased by 243.6-420.3 ℃·d compared with 1951-2000. Moreover, the active accumulated temperature increase in the northern Songnen Plain was greater than that in southern part. The ARIMA model predicted that the active accumulated temperature variation of Songnen Plain in 2018-2027 will rise, with the enhancement across the six meteorological stations would be between 25.7 and 96.9 ℃·d. The predicted values of the active accumulated temperature are within the confidence interval. The activity accumulated temperature and crop yield showed a quadratic curve. When the active accumulated temperature was below 3300 ℃·d, maize yield increased with the increase of accumulated temperature. When the active accumulated temperature was below 3800 ℃·d, the yield of soybean and rice increased with the increases of accumulated temperature.

Key words: arbuscular mycorrhizal fungi, Sorghum haipense, endogenous hormones, photosynthesis, Cs stress.