Studies On Photosynthetic Response Of Phragmites Communis To Global Climate Change On The Songnen Grassland In Northeastern China

In Songnen plain of China, we simulated increasing CO₂ concentrations by the open top chamber (OTC-I) under natural conditions. Infrared heater was used to increase the temperature. The simulation of nitrogen deposition was made by applying fertilizer. We analyzed the parameters of photosynthetic characteristics of Phragmites communis to determine the response of photosynthetic characteristics of P. communis to global climate change. The results showed that the net photosynthetic rate, transpiration rate, water use efficiency, content of photosynthesis pigment and accumulation of photosynthetic production in leaves changed remarkably in the simulation experiment. The photosynthetic pigment content, net photosynthetic rate and accumulation of photosynthate increased which was benefit for photosynthesis. However, water use efficiency and photosynthetic pigment content were decreased. The elevated CO₂ and high temperature for long time would damage photosynthetic system and reduce photosynthetic assimilation ability of plant, which would be harm growth and development of plant, eventually leading to imbalance in terrestrial ecosystem.