Abstract:

In this study, transgenic poplars and the control (Populus deltoides×P. euramericana 'Nanlin895’) were used as testing materials, and physiological parameters of photosynthesis were analyzed. The results showed that the enzymes related to C₄ photosynthesis in all the transgenic poplars increased compared with the control, and PEPC activity increased significantly as high as 38.6%. Also, transgenic poplars had strong capacity for using high light intensity, and its light saturation point increased by about 10% to 20%. The photosynthetic rates of transgenic poplars in light saturation point were higher than that of the control by a range of 17.74% to 58.1% and the light compensation points of transgenic poplars were lower than that of the control. Moreover, the ability of transgenic poplars to use low light was stronger than that of the control and CO₂ saturation point of transgenic poplars was lower than the control by 22.2% to 44.4%. Transgenic poplars had lower CO₂ compensation points than that of control by 58.1% to 76.5%, indicating that they had the ability for high-utilization of CO₂. In addition, the transgenic poplars had higher efficiency of carboxylation, and the efficiency was up to 62.3% higher than that of the control. This study provided an experimental basis for high photosynthetic efficiency molecular breeding of poplars in the future.

Key words: Populus, PEPC, transgenic, photosynthesis